Tag: Bicycles & Gear

Bikes; Wider tires

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All Kinds

The modern safety bicycle was first manufactured and sold at the end of the 19th century. Most sources recognize John Kemp Starley, the manufacturer of the Rover bicyles in the late 1880s, as the inventor. The Engineering Sport website provides a concise overview of the evolution of the bicycle. Earlier in the late 1800s some French developers tried to assert a priority to the intellectual property in the concept of the two wheeled human powered vehicle. According to David Herlihy’s the Bicycle – the History (2004) for a time in the 19th century some developers paid some royalties to avoid lawsuits for a few years.

The household/commuting/utiliity single speed bike was familiar in Europe and North America for several decades in the 20th century. The handlebars facilitated for an upright riding position. Most had horizontal top tubes; some were step-through. Most had coaster brakes. Many were manufactured with integral fenders. Some had cargo baskets or racks. Many people owned these bikes and had the knowledge and skill to inflate tires, repair a flat tire, and lubricate the drive train. The Chinese Flying Pigeon was/is a safety bicycle.

The bicycle has become more a concept or idea than a new, useful and non-obvious article of trade. The elements of the safety bicycle:

  • Two (nearly) equal sized wheels, in a frame;
  • Pedals, crank arms and a roller chain drive;
  • One wheel, usually the rear, is turned by the power of the rider pressing on pedals;
  • The front wheel can be turned on a pivot with handlebars;
  • Pneumatic tires

Bicycle manufacturing depended on industrially produced materials and components. In the the early 20th century frames were build by cutting, bending and brazing industrial steel tubing. The early safety bikes experimented with heavier ferrous metal materials, but steel tubing was lighter, easily worked and even repairable. Bike builders began to have frames and other components fabricated. Bicycles for racing on tracks or roads were custom built. Manufacturers began to offer road racing bikes, a higher value product. Then mountain bikes. Innovations multiplied. In modern times, components may be protected from imitation by patents,

Buying, riding and maintaining bicycles became more complicated. Some categories:

  • City or utility bicyles;
  • Road bikes emulate the design elements of racing bicycles used in road races. Racing was the inspiration and source of design innovations that were adopted and adapted for mass production consumer use. Design innovation has been restricted by rules of the Union Cycliste Internationale (UCI)the main competive sporting body. A few people buy ultra light or otherwise non-compliant road bikes. Characteristics of road bikes:
    • drop handlebars;
    • a light and aerodynamic frame. At one time, horizontal top tubes were favoured. Top tubes slope from the head tube to the seat tube;
    • narrow wheels and tires;
    • a drivetrain that produces high RPM for strong riders;
    • drop handlebars;
    • almost no capability to carrying anything but the rider;
  • Touring bikes and cargo bikes are designed to carry a load;
  • Cyclo-cross bikes are designed for cyclocross (CX) racing (as opposed to cross-country racing, a competion for mountain bikes). They have drop bars and resemble road bikes, but have slightly wider tires and other design variations;
  • Mountain bikes are designed for use on trails. The frames are different from other standard designs. These bike has to be stable and under control at lower speeds and during faster descents to manouver around rocks, roots and obstacles. Flat or straight handlebars are the rule. Front wheel and whole frame suspensionss are the rule. The tires are wider and run at lower pressure. Wide tires call for wheels with wider rims. Mountain bikes can be used on paved and gravel roads, but not comfortably or efficiently. They may be used to carry cargo – but do not normally have attachment points for racks. Instead, many mountain bikes have drilled and tapped fittings to hold bikepacking bags;
  • Hybrid bicycles: multi-purpose bikes designed to used on paved roads and on some unpaved surfaces. Most hybrids are upright handlebar bikes, with tires in the cyclocross range and without suspension systems. They have some capability to be fitted with racks to carry some cargo, and to be fitted with fenders;
  • BMX bikes are specialized racing bikes for special courses;
  • Children’s bikes;
  • All-road and Gravel bikes are hybrids or customized bikes blending design elements and components.

Many web pages and services discuss design, maintenance and tech in the cycling world. For instance Bike Insights discusses “geometry” (frame dimensions/sizing/ fit) – one of the ways to deduce if a bike might work for a given purpose. (Russ Roca of Path Less Pedalled inteviews the site founders in a PLP video).

Many handlebars are for the upright position. These bars are flat or straight. There is diversity in the variations of upright bars. Upright bars:

  • encourage an upright riding position,
  • support balance and control at lower speeds,
  • support a front basket or bag,
  • provide a surface area where users can bolt on bells, electronics and other accessories, and
  • provide several locations to mount a rear view mirror.

The other main category is drop handlebars. Drop bars with long hoods (brake lever assemblies) provide a comfortable fairly upright riding position with good steering control and access to brakes and shifters. As the “tops” and ramps of the bars are taped, they provide upright riding positions. Drop bars provide less space for carriers and accessories, and less locations to mount a mirror. There are alternative handlebars. Russ Roca of Path Less Paddled, the all-road, touring, gravel and bikepacking site has a video about the Velo Orange Granola Bar; and a review on the new Alternative Cycling Network of the new model flat bar Specialized Diverge. Alt-bars revive old styles like the North Road Bend.

Tires and Wheels

The dominant way of containing air is an inner tube, within a bead clincher tire. The wheel has rim or a bead channel, and tire has a bead. The tubeless tire emerged late in the 20th century. Some modern bikes are tubeless ready : tubeless wheels and tires, installed with an inner tube. Wheel manufacturers have refined the bead hook at the outer edge of the rim into a channel – to make the bead fit tightly, to let a user install tubeless tires. Bike mechanics know how to break the bead from a wheel with tubeless tire bead channel without using tools that might mar the bead or the rim. Fixing a flat at the roadside by dismounting a tubeless ready tire and replacing an inner tube may be a challenge.

Pressure affects performance on different surfaces. The conventional advice for road bikes has been, for the last few decades, to inflate tires with inner tubes to the pressure as stamped on the tire. The marked pressure is a maximum and a safety warning – it is half the pressure at which a tire will fail predictably, such as by the bead of the tire not holding to the rim of the wheel. It is not a recommended pressure to reduce the risk of pinch flats or other damage to tires, inner tubes or wheels. It is not a recommended optimal pressure. Optimal pressure depends on road, rider, and load. Sheldon Brown’s approach to tire pressure was nuanced. (The link to a Bicycling Quarterly article on the Sheldon Brown site page has gone stale – the useful equivalent is “Tire Pressure Take Home” (2016)). Russ Roca of Path Less Pedalled published an interview with Jan Heine of Bicycling Quarterly about wide tires and lower pressure, and an interview of Josh Poertner “Your Tires are Lying to You“. Wider softer tires have been becoming more popular

Tire pressure affects the accuracy of (older) cycling computers that count wheel revolutions – e.g. Cateye Mity 8 – which need to be programmed with the circumference of the wheel, usually in 1 cm increments from 170-225 cm. The circumference of a tire mounted on a wheel is affected by the actual pressure by up to 1-2 centimeters. The tire will flex under load; the distance travelled is a little less than the circumference of the inflated tire measured at the label pressure, unloaded. The difference between running wider (e.g. 700 x 38c tires) at 45, 60 or the maximum 75 psi affects how these devices record distance. Where the distance travelled on the ground is about 50 km, the effect is several hundred meters. This inaccuracy is only about .5-1%, which should not affect navigation or trip planning.

Randonneuse and All-Road

Some endurance events required that the bike should carry some cargo, and be capable of riding on rougher roads including cobbles and gravel. Sheldon Brown’s 2008 Bicycle Glossary. (His blog is maintained, and the site is updated, with many modern contributions from John Allen and other friends of cycling) has entries for randonée, randoneur and the French designer René Herse. The René Herse name is now associated with the Seattle manufacturer/shop René Herse Cycles (formerly Compass Cycles).

The randonneuse was usually a custom built bike, although some manufacturers mass produced a randonnuese model- e.g. Peugot. A randonneusse was a hybrid with road and touring features for riders in long-distance rides over mixed roads – pavement, cobbles, grave and even dirt. It was also kind of gravel bike for bike camping – bikepacking is a modern version of bike camping. A feature found on many bikes was the demi-porteur front rack which supported by a stay from the fork crown and cantilever stays above the midpoints of the blades. The load stabilized the front wheel and permitted other design variations. Another feature was that the frames had enough clearance between the fork blades and chain stays to mount wider tires and rim brakes for the rims that support those tires.

Jan Heine of René Herse and Cycling Quarterly, a student of design, writes about long rides in the Pacific Northwest, the randonneuse, and supple tires (wide and inflated moderately). Jan Heine identifies wide tire drop bar bikes – mainly the randonneuses – as the all-road bicycle. There has been a revival of interest. Several custom builders will repair or restore/rebuild such bikes. A few build new bikes to such designs.

Jan Heine regards all-road as a collective term describing randonneusses, and the monster-cross variety of gravel bike used in endurance events on routes that have gravel roads and tracks. Others use the term as including wide tired endurance road bikes.

Pedals

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Replacement

My old pedals were worn and had been damaged by corrosion after an incident in storage last winter

Platform or Clipless

Bike pedals have been flat (platform) pedals since safety bicycles began to be made and sold. Many bikes are sold with flat pedals, which riders will replace.

Bikeradar did a large survey or review early in 2021. Outdoor Gear Labs did another. Both identified several clipless cleat systems, along with Shimano’s, as choices. Cleats may be attached to the shoes with three bolts or two:

  • Three bolt cleats are large, thick, and stiff. They fit a retention mechanism on one side of a corresponding pedal. The large 3 hole “delta” cleat has dominated the market for road cleats since the Look Delta design, which Shimano emulated with its SPD-DL pedals. Shimano uses 13.5 mm M5 bolts to secure its SPD-SL 3 hole cleats to the shoes. 3 hole cleats fit fit below the sole , and only fit into one side of pedal. Most of the pedals in the Shimano Dura-Ace, Ultegra and 105 road bike product lines are 3 hole models.
  • Two hole cleats are smaller. Typically two hole cleats, including the popular Shimano SPD, cleats are used with pedals with retention mechanisms on two opposite sides of the pedal. Shimano uses 11.5 mm M5 bolts to secure SPD cleats to shoes. The cleat engagement uses a spring, adjustable by rotating a bolt in the medal. The pedal is marked to confirm the direction to turn the bolt; there is no tension marking or gauge on the pedal, (The SPD system is a mountain bike system and is marketed by Shimano for those uses.)
  • M5 bolts are the standard device to fix or secure cleants to shoes. There are “cleat nut” shoe plates that fit in soles of two bolt shoes. They are tapped for M5 bolts.

Some flat pedals, made and sold for mountain bikes, have small metal pins for grip – these depend on a shoe that will grip the pins and will not shred.

Shimamo SPD

Shimano SPD cleats support several Shimano pedals and are compatible with some OEM pedals. The SPD system has two slightly different cleats. The (black) SM-SH51 is “single direction” release. The direction is a rotation away for the crank, in the plane of the pedal – when the rider’s anke is at a normal angle to the leg, perpedicular as if the rider were walking, The (silver) SM-SH56 is “multi-directional” release which is not compatible with a few Shimano pedals.

I used a pair of Shimano PD-324 clipless pedals on a Giant hardtail mountain bike and on a Trek FX 7.4 mountain bike hybrid. The PD-M324 as originally a Deore line mountain bike “trekking” pedal. Shimano’s mountain bike product lines are complex. Deore was a line of touring components which crossed over when Shimano launched the Deore XT line in 1983. Deore is now the 4th Shimano mountain bike component tier after XTR, Deore XT, and SLX. A pair weighed over 500 g. The PD-M324 and cleat retention on one side, and a platform on the other. It was flat on both sides. I changed to Shimano PD-A530 pedals, which are similiar to the Shimano PD-A600. Both the PD-A530 and PD-A600 are Tiagra series pedals in the 4th tier of the Shimano road series. Pedals are not part of component groupsets, but Shimano identies some components as groups of related components within Shimano’s system of using product lines to market components.

Both pedals support(ed) the Shimano two hole SPD cleats on one side. The SPD is a “step in” system. Riders clip in by locking cleats on the soles of the shoes into a fitting on the pedals. The PD-A530 was lighter than the M324 at 383 grams per pair. The PD-A530 had an SPD fitting on one side and a flat ribbed surface on the opposite side of the pedal. The PD-A530 is “concave” (? convex) on the the side with the cleat fitting. The cleat lock is over spindle. This emulated the action of other cleats – it let the rider concentrate power on the central axis of the pedal at the ends of the crank arms. This required the rider to have the fitting side of the pedal facing up and get the front of the cleat into the centimeter of space ahead of the spindle. The shoe did not otherwise make other contact with peddle. The PD-A600 was a one sided pedal which differed from the PD-A530 this way “recessed SPD shoe compatible allows off the bike walking”. Jan Heine, writing in Bicycling Quarterly (Spring 2021, No. 75, at p. 108), praised the PD-A600 for these features:

  • ” .. excellent bearings
  • ” … support the rider’s feet on the pedal body … feet do not rock as you pedal”.

The PD-A600 was not on the market when I acquired the PD-A530 pedals. The PD-A600 was lighter at 286 grams per pair, and different than the PD-A530. It was no longer on the market in 2021 when I decided to replace the pedals. Shimano had discontinued the PD-A600 and moved the spd cleat into the Ultegra road bike line with the PD-ES600 in 2020. The PS-ES600 has the recessed fitting,and calling this an Ultegra product meant a price increase (to $140 a pair in Canada in the summer of 2021). Jan Heine noted some disadvantages of the PD-ES600:

  • ” … the [back] of the cage has been eliminated … means they are no longer weighted to facilitate clipping in.
  • “At the end of the ride, the cleats are sometimes hard to disengage.

Jan Heine’s comments identify:

  • the benefits of having a pedal as a platform for the foot and having a cleat recessed in the sole of the shoe that lets the shoe contact the pedal.
  • a problem that can occur with a one sided pedals. The rider has little grip on the second side if any, and a rider can lose speed before flipping the pedal and making a connection with the cleat.

Jan Heine thought the Shimano XTR line PD-M9000 mountain bike pedal worked better for his styles of riding (CX and all road, I think) than the Ultegra PD-ES-600. While the XTR is a spindle with engagement mechanisms on opposite side of the spindle – it lacks any platform, Jan Heine thought the XTR was easy to engage and disengage. He noted the that the fronts of the retention mechanisms had a a “depession that guides the cleat. The XTR pedal is considerablly more expensive than other 2 hole cleat mountain bike pedals, including other Shimano MTB pedals, and hard to find in 2021. It is built to a different standard. I wasn’t able to find one to examine. It has shallow concave scallop in the fronts of the retentions. This appears to be done by grinding. The scallop is present in Shimano MTB pedals models in the XTR grade 9000 and 9100, but other Shimano MTB pedals lack this feature.

His comparison asks questions:

  • why not use a small 2 hole cleat on an all road bike or a gravel bike?
  • is a double sided 2 hole system better than a one sided pedal fitting to a 2 hole cleat?

HT T1

Ourdoor Gear reviewed the HT T1 enduro pedal favourably and identified it as editor’s choice for a clipless system. The HT T1 was available online. It uses a proprietary cleat which does not work with Shimano SPD system cleats. (The HT X type cleats are thicker than SPD cleats, among other things). It uses a large spring which can be set much tighter than the springs in Shimano pedals. This is popular with MTB riders. See:

  1. https://nsmb.com/forum/forum/gear-4/topic/need-more-clipless-pedal-tension-129864/,
  2. https://mbaction.com/ht-t1-enduro-pedals-test/,
  3. https://bikeco.com/ht-t1-pedal-review-setup-tips/ .

The cleats are multi-directional. Twist your foot in any plane to release.

The spring is thicker and strong than the spring in a Shimano SPD pedal. Some online sources suggest that 50% on the HT indicator is equivalent to the highest tension on a Shimano SPD retention spring. The gauge in the mechanism that indicates how tight the spring is tensioned. The gauges each track the position of a threaded plate that secures the end of the bolt that tensions the spring. The gauge is a series of 8 lines along a slot in which the plate is visible.

The HT cleat retention sytem is identified as “spring binder” by LakeShoes, which offers advice about how the cleat should line up with sole of the shoe. Lake Shoes provides advice on how highly torqued the bolts holding the cleat onto the sole should be set for some pedal systems, but not the torque for the HT T1. HT has the numbers – 5 to 8 newton meters – in the product manual. HT supplied two sets of bolts to hold the cleats to the shoes. Both seem to be M5 bolts. I later threaded them into a thread checker at hardware store to confirm. Both sets were flat headed & countersunk (tapered on the back of the head). They are specialty bolts with have an opening for a 4 mm Allan Key, like cap screws. One set were ≧11.5 mm long, the standard for SPD cleats. The second set were 13 mm long, providing an extra 1.5 mm. of threaded bolt to engage with the tapped “nut plates” in the sole of the shoe. Longer bolts will project through the tapped cleat nut plate, and abrade the insole. The extra length will be required when the rider deploys shims (as shown in the Lake shoes drawings). It is almost necessary to deal thread into the cleat nut plates through the HT X type cleats.

Oops

On the return trip from the West Shore, I saw an incident when some 2 of 4 or 5 persons oncoming on road bikes lost control on the E&N in View Royal. They were riding in a group, in single file but slowed down to pass some pedestrians walking side by side, which affected riders coming from both directions and caused a momentary traffic jam. Two riders in the group went into the ditch. Bruises and road rash, and contact with the West coast rain forest underbruch. They went into the ditch on their right and did not cross into my path. I stopped and assisted, stopping and unclipping. I knew one of the riders, who used to work in the same branch of the same Ministry. This kind of incident is a risk on Victoria’s “multi-use” trails which are not set up for fast cycling, for wide vehicles, or for pedestrians who crowd or cross the centre lines of the trails.

I initially set the spring tension at 50% of maximum, which is more tension than I was used to. Within a few Km of starting my first test ride, I stopped and dialed the springs down . The cleats work like a Shimano multi direction SPD cleat but some motions work better.

I had a problem unclipping the left shoe a few Km later where the E&N trail crosses the rail line at the end of Hallowell (west and south of the Admiral’s Walk shopping centre). I was able to unclip, and continued to the Canadian Forces base gate on Admirals Road at the end of Colville. I crossed the tracks at the gate, went up Colville, turned onto Intervale and turned on the E&N from Intervale. I had unclipped and clipped a few more times. I was getting uneasy and began to looking for a place to stop. I thought I could get off on the shoulder of the next crossing street, Hutchinson. I slowed down but could not unclip my left foot. I was able to get some support from the chain link fence which is immediately beside the trail – on the left. I was able to, unclip my right foot for support and mobility, undo my left shoe and get the bike off the trail. I was not able to get at the bolts holding the cleat. I undid the bolt that pre-tensions the retaining spring, release my left shoe, and remove the cleat from the shoe – without losing any more parts. One of the two cleat retaining bolts had worked loose and had disappeared. I was able to put the shoe on and ride home, using the left pedal as a platform pedal. The GPS stopped recording when I stopped. The walk off the trail was too slow to restart recording until I was on the trail and pedalling. The gap shows my move to the wrong side of the trail but is otherwise nearly invisible in my GPS track of the ride. Later, I reassembled the cleat retaining spring; and

  • confirmed, with the thread checker in a hardware store that the bolts are standard pitch M5 bolts;
  • found standard pitch M5 bolts 16 mm long at 2 hardware stores. Both stores had M5 zinc (plated) steel bolts, flatheaded and countersunk, with slot or Phillips heads. Either would work. There are shortages of all sorts of things (the economy has been disrupted by Covid and the other shocks of 2020-21) and having the bolts in hand provides options,Phillips heads have some advantages but come with the risk that the bolt head strips and rounds when torqued. With some enquiry and looking around, I located M5 stainless steel bolts, flatheaded and countersunk, with Phillips heads. Still vulnerable to rounding, but a bit stronger. I cut them down to ≤13 mm with a Dremel tool, and reinstalled the cleat.

The cleat retaining bolts should be fully engaged and torqued to the manufacturer’s specification to avoid the risk of losing a bolt, which will probably lead to being unable to unclip. Jan Heine describes voming to a stop with your foot stuck in the pedal as one of the worst nightmares of any cycist. I agree. I was lucky in not crashing, and in finding the repair parts. I fixed the problem and reinstalled the cleats properly.

This system signals cleat engagment with a firm click that I can feel and hear. The pedal provides a platform for pedalling unclipped. It has 2 pins at the front which allows me pedal and make a second try to find the front of the spring and clip in if I miss on getting the front of the cleat into the front of the spring.

Tubeless Ready Tires

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A new feature and experience

This started with my discovering the difficulties of dismounting tubeless ready tires from my gravel bike in the fall of 2019 and the spring of 2020. Changing a tire is not supposed to be a job requiring shop time. Tires, in principle, can be repaired and replaced by a user.

Clinchers

The pneumatic bicycle tire was one of the technologies that made the safety bicycle successful. It evolved by innovations in wheels, wheel rims, tires and inner tubes into the clincher used on most bikes, including the utility bikes common in 20th century. The tire casing is a laminate of fabric and rubber. The tread is hardened rubber laminated onto the casing.

The Bicycle Technical Information (“BTI” ie Sheldon Brown) tires page discusses the kinds of tires, including the tubular tire used in racing. The dominant technology uses clincher tires and inner tubes. The BTI page on flat tires summarizes. This illustration (from a Wikipedia page) shows a tire, tire bead, inner tube, bead channel and hook, in a cross-section view. The diagrams and pictures at Bike Gremlin, Bike Touring News and Cycling Tips (below) also illustrate.

  1. rim;
  2. rim tape, in a central well or valley (in a tubeless ready wheel);
  3. rim braking surface (on a wheel for a bike with rim brakes);
  4. bead, laminated to tire casing, engaged by the bead hook in the bead channel;
  5. inner tube;
  6. casing;
  7. tread.

Pneumatic tires became the dominant technology for automobiles and motorcycles. The tire industry developed tubeless tires and rims for motorized vehicles and for lightweight carts and appliances.

Tubeless bicycle tires were developed for mountain bikes and gradually acccepted for use on other bikes. Tubeless tires are supposed to recover from minor punctures during a ride and repaired later. Tubeless tires are used at lower pressure than the same tire with an inner tube, which is desireable in many kinds of riding. Tubeless ready rims and wheels have become, arguably, the standard equipment for new bikes in many price and quality classes. A tubeless ready tire is a tubeless tire without the sealants and the tubeless valve. It is basically a clincher, and requires an inner tube. Some tubeless ready wheels have rim tape, but not all of them. The rim tape may extend over the shelves of the bead channel. Many riders carry an inner tube to repair a tubeless tire in the field.

Cycling Tips, an online publication, published a guide to tubeless tires, An Endless FAQ, in 2019 and updated it in 2021 [updated October 2021].

The tire and the rim

The normal process for detaching (unmounting) a clincher tire and replacing an inner tube is shown in this Park Tool video. A clincher normally disengages from the rim easily when the tire is deflated. After disengaging the bead, it may be necessary to use tire levers to get the bead off the rim. Hydraulic, pneumatic and manual bead breaker devices are available and basically necessary for agricultural, industrial, truck, automobile and motorcycle tires, but such devices are not used in bike shops and almost never available for a roadside repair.

It is harder to unmount a tubeless tire than an ordinary clincher. Tubeless tires fit tightly. Friction between the tire casing over the bead, and the bead channel in the wheel rim is a major factor. The bead channel may be machined to wrap around and hook over the bead. If the tire was mounted with sealant for tubeless use, the sealant may a factor. When the tire has been deflated, the bead has to be pushed off the shelf into the valley in the middle of the rim. It is necessary to unhook the bead and push it into that valley. This takes some force, but can be done without tools or extreme measures. It may be necessary to work around the rim and push in at several places and find the best place to gets the bead out of the channel and continue around the rim and get it out of the channel before pushing it into the valley. It may be necessary to do this on each side. I found videos of methods for extreme instances on YouTube:

Some sources advise riders to practise the skills of dismounting a tire and installing or changing a tire in order to reduce time lost on a ride. This skill involves tactile feedback and muscles that may not have been worked that intensively for some time. It is worth learning.

Mounting and inflating

It is easy to press one bead into the rim. The user may want to align a marking on the sidewalls with the valve hole at this stage. The inner tube can be pressed into the tire when one side of the tire has been pressed into the wheel. The inner tube should be empty or nearly empty. The valve stem should be pressed through the hole in rim, and the inner tube positioned with the stem perfectly perpendicular to the rim.

Getting the remaining (second) bead into the rim can be done by hand if the beads are kept down in the rim channel. It is better to run fingers along the sidewall of the side that is already on the rim to make sure it is in the well. The remaining side can be pressed into the rim, starting some distance from the valve. It may be best to start opposite the valve. About half of the remaining side will fit easily, but the rest will also yield. It can be worked in short sections. It may be necessary to pinch both walls to make sure the first side is still in the well. It may be necessary to hold the bead down in one place with one hand while working the bead that is still outside along the rim with the other hand. Eventually, the section still outside the rim will be short enough that it can be be pulled into the rim. It can be done by hand. Using tire levers to pry the tire over the rim presents the risk of catching the inner tube and creating a pinch flat.

It is advisable to work the fingers of one or both hands along the sidewalls to find any places the tube may protruding outside the edge of the sidewall or caught, and press the sidewalls back to release the inner tube. The sidewall can be rubbed and pulled up into the bead channel. A tubeless rider will follow a similiar process, but will need to take extra steps to get a preliminary seal.

Presta Valve

If the valve is a threaded Presta valve – which is common on modern bikes, the captive nut (which threads on the thin rod that fits inside the stem) should be tightened down. This locks the valve core in the closed or sealed position. The BTI glossary entry on the Presta valve and several articles by Jobst Brandt are informative. The presta valve has an internal stem that seals the valve, which is locked by a tiny nut threaded on a thin brass rod. A Presta valve does not have an internal spring. The stem rod can be easily bent or damaged! It is worth a little preventative care, and some caution in use. The external cap that threads onto the exterior of the stem does not have retain air, but provides some protection against impacts on the stem cap rod.

The stem cap rod is brass, and bends. One risk it that a pump hose, a pump or a pressure gauge can bend the stem cap rod while the device is being attached to or removed from the valve stem. The threads cut on the outside of a Presta stem can in theory be used to screw on a pump hose but that is rare – many chucks friction fit over the end of a stem or are locked with a lever.

If the tube seems to be leaking from the valve core, and core is a removable threaded core, it is worth tightening the core with a tool (that can grasp the part of the core above the end of the valve stem).

When both beads appear to be in place, start pumping. The beads of a tubeless tire often will audibly pop into place. The valve stem may have a jam nut that threads onto the outside of the stem to hold the stem in the wheel rim. See above – this nut should be tightened down.

Tire Pressure

The pressure marked on a tire is a consumer protection warning – a fraction of pressure that will blow the tire with an inner tube off the rim. It is not a recommendation for performance. High pressure was believed to lower rolling resistance, but that theory or belief has been contradicted. The operating pressure is normally much lower than the marked pressure. The maximum pressure for 700c x 38 with an inner tube is 75 psi. I ran the Panaracer Gravelking SK at 60 psi; I got less rolling resistance in the low 50’s and mid to high 40s (psi). For a 38-40 mm tire, with an inner tube, the pressure will be in the 3 to 3.2 bar range or lower. The recommended pressure for tubeless use is even lower. Fatter tires run at lower pressures. The appropriate pressure depends on several factors. The modern thinking is stated in this Cycling Weekly article. There are some good online calculators; a couple are noted in the article. I have used the Silca calculator. The full “pro” version is free, although at this time it requires registration by entering an email address.

Topstone 105 – Wheels, Tires, Fenders

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Clinchers; Tubes and Tubeless

In the early 21st century, the most common bicycle tires are pneumatic clincher or bead clincher tires. The tire has a bead, formerly made of metal wire. Modern tires are manufactured with material that can rebound into a circle after being folded for packaging and shipment. The tire contains an inner tube, which is soft and vulnerable to punctures and tears. Clincher wheels curve into a bead hook at the rim to catch and hold the bead. In tubeless wheel, the rim has

  • a central groove which can be described as a valley or well;
  • a rim strip to seal the spoke holes
  • bead channels – the spaces between
    • a shelf, between the rim wall and the well, and
    • a bead hook.

Tubeless tires are clincher tires sealed and inflated directly – no inner tube. Tubeless systems generally require sealants installed in the tire; tubeless tires are supposed to self seal to mitigate small punctures. Riders may carry inner tubes to install a tube in a tubeless tire to mitigate a larger puncture. A tubeless tire bead is designed and manufactured to fit into tubeless wheel rims. A tubeless or tubeless ready wheel has a machined bead channel. The beads and the rim channels are supposed to fit tightly enough to be air tight when the tire is inflated. The seal is normally obtained by applying tire sealant to the edge of the side walls along the bead.

The wheels on my 2019 Topstone are “tubeless ready” WTB i23, a metal alloy with a 23 mm rim; the 23-622 model. (WTB has versions of i23 including a “26 inch” mountain bike rim, and i23 (23-622) for 700c tires from 700c x 32 to 700c x 46). The 23 mm measurement is taken between the rims in the bead channelat bead seat. The tires were “tubeless ready” WTB Nano 700c x 40. Some manufacturers (e.g. Mavic) manufacture rims and tire beads to the Uniform System Tubeless (UST) standard. The bead seat is designed to accept and hold the beads of UST tires without tape. WTB’s tubeless metal rims are sealed with plastic rib tape (liner) which adheres to the rim. The rim channel and wheel beads are beadlock – which is WTB’s way of saying manufactured to the UST standard. WTB, like other manufacturers, calls tubeless tires a modern improvement or feature and calls its beadlock system a feature. It is hard to unmount a tubeless tire from a rim to replace a tire or to fix a flat. It requires a skill that has to be learned. It can be a problem with some wheels and tires as noted in this YouTube review of the Topstone (at the end of the 3 minute video). I

Tire sizes are normally described by height. Height is the diameter across the wheel on the outside of the tire, measured on the mounted and inflated tire. The height is the nominal exterior diameter of the tire, which was used by manufacturers of tires and other components. 700c was the term used in a French system. The height, assuming the tire is a perfectly round torus, should be the diameter of the rim plus the 2 x the diameter of the tire. For 700c x 28, this works out to 678 mm which is almost 28 inches (700 mm. = 27.559 inches) . The tire, inflated, has an irregular oval cross section, sort of egg or pear shaped. Diagram below. A tire is always marked with a tire size in a nominal diameter system, and a size in the International Standards Organization ISO or ETRTO system. The most common tires on gravel and all-road bikes are 700c tires – considerably fatter than 700c road bike tires. 700c is a standard for tires with a nominal outside diameter around 700 mm (28 inches). There are skinny 700c x 25 (ISO 25-622) tires and fatter 700c x 36 (ISO 36-622) tires. The 622 in the ISO descriptions of 700c tires refer to the 622 mm diameter of the wheel.

700c (ISO 622) is also the standard for describing larger “niner” and “niner +” (29 inch x 2+ inch) wheels. 650b is a standard for tires with a nominal diameter around 650 mm (27.5 inches). The ISO descriptions of 650b tires refer to the 584 mm diameter of the wheel and the tire.

The other number in the nominal diameter or ISO description is the bead seat diameter (“bsd”) – the width measured across the tire or the rim at at the inner bead seat where the tire bead fits into the bead seat of a wheel. The width is usually the same in the nominal diameter and ISO systems. There are some outliers. A tire may be 700c x 38 and 622-40.

A higher bsd means a fatter tire, mounted and inflated, with a larger diameter and circumference than a narrow tire. The actual thickness (width from sidewall to sidewall, from the outside)≥ bsd. Actual thickness varies, depending on pressure and load. For higher bsd numbers, the thickness starts to push out. Height (outer diameter) and thickness can vary slightly depending on the construction and inflation of the tire. The height and thickness of some tires:

Tire SizeISOCircumference ≅Diameter (C/π )ThicknessSource
700c x 1818-622Generic/Standard2070 mm658 mm
700c x 2525-622Generic/Standard2111 mm672 mm
700c x 2828-622Generic/Standard2130 mm678 mm≅ 28 mm
650b x 5050-584Generic/Standard2149 mm684 mm
700c x 3838-622Generic/Standard2180 mm.694 mm

Clearance

The rear tire has to fit between the chain stays behind the bottom bracket and between the seat stays below a bridge below the seat. The bottom bracket shell accomodates a bb and a crank with a suitable Q factor. On the Topstone, the chain stays are straight and parallel to each other for a few cm behind the bottom bracket. The distance between the chain stays is about 56 mm in the parallel section where a 700c tire would have to fit. The The seat stays are straight and bend out to fit around the rear axle assembly (cassette and disc brake rotor). The distance between the seat stays is 66 mm where the tire runs. The front tire has to fit between the fork blades under the fork crown. The distance between the fork blades where a tire runs is 61 mm or more. (The measurements were made with a caliper with the wheels on the bike). The side clearances allow 700c x 40 mm tires. The clearances at the tops of the tires under the seat stay bridge and the front fork crown were tighter. The WTB Nano 700c x 40 tires were too big to allow for fenders. For subsequent model years, Cannondale shipped the Topstone with 700c x 37 WTB Riddlers, a slightly smaller and narrower tire (with small knobs).

The WTB Nano tires had a mountain bike type tread. The tread on the center line of the tire was made up of chevron shaped groups of cleats or knobs. There were alternating gaps in the chevron. I thought the tread caused vibration, noticeable at low speeds; experienced gravel riders reviewing it thought it made for a smooth ride. I agreed it was smooth unless speed dropped to under 12 km/h. I did not need cleat or knobs e for my riding on asphalt and packed gravel. I downsized the tires to 700c x 38 Panaracer GravelKing SK tires.The dense small knobs were smooth to ride, although I expect some drawbacks.

Some all-road and gravel bikes can be adapted to use 650b wheels and tires. The 650b standard is based on a 584 mm. diameter wheel. A 650b x 48c (ISO 48-584) wheel is as tall as a 700 x 28c. It has more rubber, and is wider and heavier. 650b x 48 is not as tall as a 700c x 38; it will fit into the fork under the fork crown and the seat stay bridge. René Herse states that its 650b x 42 tire is 41-43 mm wide, and its 650b x 48 is 49-50 mm wide. These tires will fit within the clearances in the Topstone, but fitting a 60 mm diameter fender for 48 mm tires would be awkward.

Fenders

Fenders were normal part of the design of all-purpose bikes used by commuters and city riders, and installed by manufacturers for most of the 20th century. Road bikes, imitating racing bicycles, were built without fenders or even mounting points for fenders. While fenders were useful for some uses of mountain bikes, fenders were hard to design. manufacture and install. Fenders for road bikes, hybrids, and mountain bikes became accessories. Fenders were more popular on touring bikes and endurance/randoneusse bikes.

To fit fenders, the rider needs to know the thickness of the tires, and the clearances in the bike frame. The front fender has to attach to the fork at or near the fork crown. The rear fender needs to attach to the frame behind the bottom bracket between the chain stays, and at a bridge between the seat tubes. The attachments at those points support the front parts of the fender in the proper position. Fenders stays hold the back parts of the fenders in position. Fender stays normally attach to the frame and the fork near the axles.

A fender should fit around an inflated tire, with horizontal and vertical clearance. The exterior diameter of the fender, measured across the base of the arc of the fender indicate that the fender needs that horizonal distance to fit between the seat stays or fork blades without cutting or bending the fender Velo Orange, a manufacturer of aluminum fenders, suggests an 8 mm. horizonal difference between the exterior diameter of the fender and the bead seat diameter of the tire. This suggests a 700 x 40c tire needs a 48 mm exterior fender. A fender should clear the tire vertically (along the radius of the circle) by about 20 mm where the fender covers the tire. There has to be a vertical gap of more than 20 mm from the inside of the fork crown or the seat stay bridge and the outside of the tire.

My first fenders for the Topstone were SKS P50 Chromoplastic Longboard Fenders, a popular model sold in many shops and online stores in the USA and Canada including Modern Bikes and Universal Cycles. SKS marketed these fenders as wide enough to cover 700c tires in the range from 700c x 38 to 700c x 45. The P50 fenders had an exterior diameter of 50 mm. Plastic is light but it is prone to twisting and vibration. The rear ender mounted easily to the eyelet between the chain stays behind the bottom bracket. SKS, like other fender manufacturers provides a fender bridge that has to be bent around the outside of the fender and crimped around the edges. This bridge has to be centered on the fender to align to the frame mounting fitting on a bridge between the seat stays, slid into position and crimped onto the fender. If this is not done successfully, the fender will be twisted out of true. There is very little margin for error . SKS chromoplastic fenders use V shaped stay ; each stay has 2 arms. These stays are designed to attached to eyelets at the ends of the chain stays. The stays did not quite line up to eyelet . I had to adapt some left over parts from a rack mount kit to fabricate little fins. I had to bend the stays out to balance the tension to keep the fender from rubbing, but it worked.

The front fender fit under the fork crown and appeared to have adequate clearrance over the tire, but did not clear the original 700c x 40 knobby/cleated WTB Nano tire. I downsized the tires. The next problem with those fenders was the lack of eyelets for fender stays at the ends of the fork blades. The only eyelets stays are on the inside of the fork, 15 cm above the end of the fork. This was not a good place for the SKS breakaway tab or for a V shaped stay. I was able to improvise an attachment for the SKS break-away fender stay mount, and bend the V arms of the stays to slide into the attachments on the fender. This worked for my rides in the winter of 2020-21. I began to get a rubbing noise at higher speeds on chipseal. The V stays did not support the plastic fender under those conditions.

Riders reported installing SKS plastic fenders on Cannondale road bikes in forums, Reddits and YouTube, but these riders referred to bikes with eyelets at the end of the fork blades. One English rider reported, in a YouTube video, using the Bontrager NCS plastic fenders on a Topstone with carbon forks. That fender has a single straight (adjustable) stay, which normally attaches to an eyelet at the end of fork blade, but can be attached to the eyelets on the Toptone. I installed aluminum Velo Orange fenders. These are light but rigid, and attach with a single stay on each side of the fender. This is how the stays fit, using the pre-drilled holes for the stay:

Carbon Fiber Fork

Carbon fiber forks are offered on many production road and gravel bikes with steel or aluminum alloy frames. A carbon fiber fork is light and stiff, which is supposed to improve steering, although this can be debated. A carbon fork on bike with disc brakes has to be stiff. A stiff fork does not dampen vibration. Many carbon forks lacks eyelets for racks and other devices, which limits some uses of the bike. The carbon composite must be laid over a metal component tapped to receive a bolt and act as an eyelet. This is tricky and expensive.

Crankarms and Cassette

I changed the stock 172.5 mm crankarms to 165 mm – a shorter radius and less stress on knees. I replaced the Shimano 105 11-32 cassette for an SRAM PG-1170 11 cog 11-36 for a couple more low, climbing gears. With the 30 tooth front ring, this change gives me 30×36 as the lowest gear.

Cycling computers & GPS

Table of Contents

Classic

Original or classic cyclometers measure and display distance, time and speed. The devices could be powered by button cell batteries. These units had (or if in use, have) a magnet that clips onto a spoke which rotates the magnet past a sensor. They count rotations and process data to display speed, distance and time. The original models had a wired sensor; more modern models have wireless sensors. These devices need to be programmed with the circumference of the wheel to calculate how far the bike moves forward each time the wheel goes through a full revolution. The tire will flex under load; the distance travelled is a little less than the circumference of the inflated tire measured unloaded. Cateye had a chart in its manuals, listing the circumferences for dozens of tires, including several 700c tires from 700c x 18 to 700c x 40. Similar charts are online in support articles by Sheldon Brown and by volunteers in the public knowledge base at newwheel.net. I had a Bontrager (Trek) computer on my Trek hybrid – it gave the user choices of tire size in a menu rather picking a circumference in the menu. These systems assume uniform tire sizes, inflated to the rated/marked maximum. The circumference of a tire on a wheel is affected by the tire pressure. It is small inaccuracy, only a centimer in 200 (½ of one percent).

Most units could be calibrated to one bike; a few could be programmed to two bikes. They may pause and appear to “sleep” if the rider stops for longer than a couple of minutes. It depend on the device, default settings and user choices. Setting them up is time consuming and balky.

The monochrome displays were visible even in bright sunlight and under low light conditions.

GPS

GPS was not available to cyclists until the US goverment allowed non military users, after the year 2000, to receive satellite signals from Global Positioning Satellites and calculate position on the ground to within 5 meters. This provided enough accuracy for navigation and tracking distance and speed. A cycling GPS head unit will measure distance accurately and “save” the ride in memory. It may lose a few meters as the device may need a few seconds to recognize when the rider has started to move after halting. The device may lose satellites in tree cover, and falter in calculating velocity or elevation changes. The rider usually has to power the device on, and the device then usually starts to record the session as a new ride or a lap. There are some nuances to setting up a device. Setting up and learning the unit requires time and attention, as changing anything during a ride takes time and reference to manuals and resources that may not be available.

Garmin, having produced watch sized GPS units for runners in 2003, began to produce and sell the Edge GPS receiver for cycling in 2005. Garmin added functions including rear radar, lights, power meters, electronic shifter controls, touch screens, colour screens, maps, navigation and voice prompts in more evolved and expensive head units combined with peripherals. The units for sale bundle primary functions with functions used occassionally by some users, and with some specialized functions and features. Garmin has added GPS functions using the alternative satellites of the Russian Glonass system and the EU Galileo system. Competitors including Wahoo have entered the market.

Basic models do not display a map or provide navigational prompts. Some can be paired with smartphones which may, if they are using wireless data, be able to display maps. A large screen displaying a map is useful if the rider can stop and check, but can be a distraction. The marriage of the GPS cyclometer to cloud computing, big data and social apps means cyclists are sharing their location data with the device manufacturer network and its partners. If the device network servers are hacked, as Garmin was in July 2020, users can lose access to functions that depend on the servers in the cloud. It may not matter much if the cyclist is only using the head unit to display and record distance and speed.

Smart Phones

It seems to be efficient to use a smart phone app on a phone that you already own, and to not acquire a head unit but there are trade-offs.

Smart phone mapping apps will tell a user where the user is on a map but do not necessarily calculate distance and speed in real time. These apps use the GPS receiver and sensors in the phone, and the location services of the OS ecosystem. The GPS receiver is not as good as a dedicated GPS head set; these apps do not appear to record distance as accurately as GPS headunit or a classic cyclometer. Google had MyTracks, an app that ran in Google Maps, but killed it in 2016. The cycling, running, walking and hiking apps push ads, harvest data and self-promote paid apps with better “features”. I am not happy mounting a phone to handlebars or using battery power and cellular data.

My Gravel Bike

Cannondale Topstone 105

My Cannondale Topstone 105 Alloy is a gravel bike by Cannondale, a subsidiary or brand of the Canadian conglomerate Dorel Industries, manufactured in Taiwan. The frame is an aluminium alloy. This is what it looks like

This Cannondale model is named for the Shimano 105 groupset which is marketed by Shimano as a road groupset. It has several Shimano 105 branded components: brakes, shifters, 11 cog cassette, and derailleurs. The crankset was FSA, with 172.5 mm crank arms, and 46/30 rings – a “compact” road bike crankset. The largest cog on the rear cassette was 34 teeth; lowest possible gearing was 30 to 34. The lack of more climbing gears is a flaw of this and other production gravel bikes.

The 2019 Cannondate Topstone 105 Alloy has a profile at Bike Insights. It is neutral on the upright/aggressive scale. It is a neutral mid trail bike. Cannondale builds it in 5 sizes that it calls XS, SM (small), MD, LG, XL. I bought the medium size, which means, according to the datasets used by Bike Insights:

  • The seat tube is 505 mm long;
  • The “effective” (horizontal) top tube length is 561 mm;
  • Stack 579 mm; Reach 385 mm – Average for category;
  • Trail: 63.7 mm;
  • Chainstay (horizontal) 423.4 mm.

The Cannondale Topstone 105 shipped with tubeless ready WTB ST i23 TCS wheels and 700c x 40 (ISO 40-622) WTB Nano TCS tubeless ready tires. The tires are knobby, like many mountain bike tires and cyclo-cross tires. 700c x 40 may the largest/widest tires that run on this bike.

There are eyelets at the drop outs for the rear wheel and on the seat stays to mount a rear rack, but the chain stays are short which limits the use of panniers for touring storage. The stays are widely separated for wide tires and disc brakes. There are eyelets behind the bottom bracket, on the seat stay bridge and at the rear dropouts for a rear fender. Some racks and fenders can be fitted.

The carbon fiber fork lacks the front facing mounting point at the fork crown found in bikes with rim brakes. There is a rear facing eyelet at the fork crown for a fender with an L-bracket. There are no eyelets on the outside of the fork blades. There are eyelet on the inside of each fork blade 150 mm above the axle drop-out. The limits the options for front racks, and bags:

  • A demi-porteur randonneur rack requires a front-facing eyelet at the fork crown and eyelets above midfork to mount the cantilevers;
  • A low rider front rack requires eyelets at the drop-outs;
  • The cable routing along the drop bars limits the options for proprietary mounting braces (eg. Arkel, Salsa); the space between the drops and brake levers.

The frame has several eyelets for bikepacking bags and accessories.

Rack

I tried to use the Tubus Logo Evo touring rack that I had used on my Trek. It fit on the wider chainstays (longer rear axle) of a disc brake bike with modification of fit kit parts. I was able to install a Tubus Vega, which can carry a trunk bag. The point is to carry some tools, an inner tube, some clothing and little food. The rack legs and the bolt heads for fender stays interfered with the rotation of the thru-axle handle. The thru-axle may have to removed to remove the wheel for maintenance and repair. The handle may be removed with a 4 mm Allen wrench, but when that is done, a larger (e.g. 12 mm) fixed wrench (combination or open end) will be needed to release the axle. An after-market rear axle (Robert Axle Project) that can be removed using a 6 mm Allen key was part of the installation of the rack.

A New Bike

Table of Contents

Variety

I shopped for a new bike last summer (2019). The literature of bicycle manufacturing is vast. The Guardian published a survey and list of printed works in 2016. Some books and resources address innovation and engineering:

Many books are about competitive events – or the special bikes used in competition. Racing on tracks and roads became the most visibible use of bicycles at the end of the 19th century. The single speed utility bike with coaster brakes was the common bike for much of the 20th century.

Much of the innovation for riding on trails and rough roads came in the mountain bike and BMX sectors in the last 4 decades of the 20th century: frame design, wheels, wide tires, cleated tires or knobby tires for traction in mud and on climbs and descent on bare ground, wider gear ranges, more efficient brakes. Mountain bikes have been discussed in books, but seem to have been discussed in on the internet – for instance in inteviews and discussions like The genesis of the mountain bike, according to Tom Ritchey, published at Handbuilt Bicycle News in September 2016. [Update – August 2021. The Cyclist Magazine’s Podcast Episode 34 interviewed Tom Ritchey in two parts on July 8, 2021 and July 16, 2021. Tom Ritchey raced track as a teen and began to repair his own frames. He was a mountain bike pioneer. His company also makes highly regarded road bikes.] Special gear was developed – e.g. frame bags for mixed terrain cycle touring (i.e. bike-camping or bikepacking). Mountain bike races on unpaved roads and trails, touring on back roads, bike-camping and adventure rides became popular. Mountain bikes permitted new kinds of competition. Cross-country mountain bike (XC) races became organized, and competition became specialized into XC, downhill, endurance and other events. Endurance blossomed into multi day ultra distance events along difficult and challenging routes such as Tour Divide and Trans-America.

Cyclo-cross (CX) racing is a competitive event in cycling, for riders on drop bar bikes. Cyclo-cross bikes are similar to road bikes with wider, knobby tires for traction and other features for races off of paved roads. As road bikes tended to use narrow tires at high pressure, road bike frames often did not have clearance for the right tires. Some mountain bike innovations were adopted to design and manufacture CX bikes, including tire clearance. CXbikes retained nearly horizontal top tubes, for reasons related to conditions of those races. For some applications, users and shops began to adapt and develop monster-cross bikes.

The Union Cycliste Internationale (UCI), the international sporting body has rules or standards for track and road racing, CX, mountain bikes and BMX. The rules are seen as restricting technological innovation in cycling. UCI has recognized gravel in September 2021 – UCI announced sanctioned gravel events in 2022.

Gravel

Road bike riders began to use unpaved roads more extensively for training and recreation, and to participate in Ultra cross and endurance events on rough roads. Randonneur rides became more common. Gravel grinders – races or endurance events on gravel roads. Some custom bikes and adaptations provided some advantages in such events. Gravel riders started blogs or published on sites like Gravel Cyclist. Salsa (a subsidiary of the conglomerate QBP released the Fargo, a fat tired bike with drop bars, a “mountain touring bike” in 2009 (it has since become favoured as a touring bike), the Vaya gravel/touring bike in 2010, and the gravel racing Warbird in 2012. Other manufacturers moved into gravel bikes. Production gravel bikes incorporate technical innovations from road, mountain and all-road: disc brakes, threadless headsets, internal frame routing for cables, indexed shifting integrated in the brake levers, tubeless ready wheels and tires. Gravel bikes with disc brakes will usually have thru-axles (as opposed to quick release skewers). Thru-axles fit to closed drop outs with threaded fittings for the axle at ends of the fork blades and the rear stays. Some have suspension forks in the front; some manufacturers have some types of rear suspension.

The features of gravel bikes:

  • wider tires than road and cyclo-cross bikes. Most new gravel bikes are shipped with cleated/knobby tires – an imitation of the way mountain bikes a shipped;
  • most gravel bikes have drop bars; the drop bars are often wider, flared, and shaped differently than the drop bars on road bikes (article at Bikepacking.com);
  • the geometry is different;
  • gear combinations for moderately fast riding and moderate climbing:
    • a single chainring or a two ring set (similiar to a road bike compact -a large ring with 46 teeth instead of 50 or 52 and an inner ring with 30 teeth);
    • 10 or 11 cog rear cassettes. a range from 11-34 teeth would be normal. Riders can customize for small increments or larger gears for climbing.
  • eyelets for frame bags, and for racks to carry panniers

Bike Insights describes the typical attributes of all-road/gravel bikes:

  • Wider, smooth or treaded tires, typically from 38-48 mm;
  • Trail (a design geometry concept related to the head tube angle and the responsiveness of steering) around 57-71 mm for improved handling off-road;
    [Update – an article from Cycling tips on design geometry]
  • Short to mid-length chainstays of 421-443 (Touring bikes have longer chainstays to allow riders to carry panniers in rear racks).