12 Myths in Cycling (1): Wider Tires Are Slower

When we started to publish Bicycle Quarterly 15 years ago, it seemed that most of the technical aspects of bicycles were well-established. And yet, as we tested many different bikes, we started to question many of the things we had accepted as ‘facts.’ To celebrate our 15th anniversary, we’ll look at some of these myths. We’ll explain why we (and everybody else) used to believe them, and how things really work. Let’s start this series with the biggest one:

Myth 1: Wider Tires Are Slower

For almost a century, cyclists ‘knew’ that narrower tires roll faster. Some people realized that in theory, wider tires are faster due to their shorter contact patch, which deforms less as they roll. But the thinking was that in practice, the lower pressure at which wider tires must run limited their performance. If you wanted to go fast, you chose narrow tires.

That is what we thought when we started testing tires almost 12 years ago. And yet, as long-distance riders, we wondered whether the narrowest tires, pumped to the highest pressures, really were optimal for us. What if wider tires were a few percent slower, but their greater comfort reduced our fatigue? Remaining fresh toward the end of a long ride would help us put out more power, so we might go faster in the end. What we needed to know was how much speed we would give up by going to wider tires.

Real-Road Testing

So we started by testing 20, 23 and 25 mm tires (same tire model). Imagine our surprise when the 20 mm were slowest, and the 25 mm fastest. This wasn’t what we expected! And yet, when we repeated our tests with a different methodology (power meter vs. roll-down), the results remained the same. There was no doubt that the narrowest tires are slower than slightly wider ones.

Then we tested wider tires, and realized that, once you go wider than 25 mm, the performance of tires doesn’t change as they get wider. Since then, we’ve tried to figure out how wide a tire can be before its performance begins to drop off.

We’ve used the results of our testing to develop our Compass tires, which are optimized for performance and comfort on real roads. And since we now have very similar tires in widths from 26 to 54 mm, we could do controlled testing of all these sizes. We found that they all perform the same. Even on very smooth asphalt, you don’t lose anything by going to wider tires (at least up to 54 mm). And on rough roads, wider tires are definitely faster.

As we did more research, we realized that cyclists used to know this. When pneumatic tires were first invented, the fast-riding ‘scorchers’ used wide tires, because they rolled over road irregularities better. And in the 1920s, Vélocio, the editor of the French magazine Le Cycliste, discovered that as long as wide tires had supple casings, they rolled as fast as narrow ones. But all this was forgotten in later decades, as racers went to narrower and narrower tires.

Why did it take almost a century to rediscover this? There are two reasons why cyclists used to believe that narrower tires were faster:

1. Laboratory tests on steel drums eliminate the rider and thus the suspension losses. If you look at hysteretic losses alone, narrower tires run at higher pressures and thus flex less, meaning they absorb less energy.

We tested on real roads, with a rider on the bike, and found that the increased vibrations of the narrower tires caused energy losses that canceled out the gains from the reduced flex. These suspension losses are mostly absorbed in the rider’s body. Imagine a bean bag that drops on the ground without bouncing back – all the energy is absorbed by friction between the beans. The human body works similarly. Studies by the U.S. Army found that the more discomfort vibrations cause, the more energy is being absorbed.

2. Placebo effect: The faster we ride, the higher the frequency at which our bike vibrates, because our tires encounter road irregularities at a higher speed. However, narrower tires also increase the frequency of the vibrations they transmit. Basically, a bike with narrow tires feels faster even though it may actually be slower. Inflating your tires harder is a simple way of tricking your brain into feeling that you are going faster, but if you have a bike computer, it’ll tell you that you haven’t actually increased your speed. Conversely, wide tires vibrate less, and thus feel slow to most cyclists.

So for almost a century, narrow tires felt faster, and they tested faster in the laboratory. There was little reason to question whether they actually were faster. It took Bicycle Quarterly‘s real-road tests to show that a vibrating bike (and rider) is absorbing energy that reduces the bike’s speed.

What all this means is that you can have your cake and eat it, too. If you run wider tires at lower pressures, you increase the flex of the tire (negative), but you reduce the suspension losses (positive): the two effects cancel each other, and your speed remains the same.

This also explains why supple casings make such a huge difference in tire performance: They are easier to flex, so they absorb less energy. And they absorb vibrations better, which reduces the suspension losses. So they use less energy on both counts. Talk about a win-win scenario! And of course, since they absorb vibrations better, they are more comfortable, too.

Aerodynamics

What about the aerodynamics of wider tires? Many riders believe that wider tires will be slower, because they have more wind resistance. We tested this in the wind tunnel and found that the difference between 25 and 32 mm tires was too small to measure reliably in a real-world scenario. The German magazine TOUR built a sophisticated setup with a motorized dummy rider and found that a 28 mm-wide tire had the same wind resistance as a 25 mm tire when the wind was coming from straight ahead. With a crosswind, the wider tire was very slightly less aerodynamic. Even then, the wider tires required only 5 watt more – on real roads, the reduced suspension losses probably make up for that.

We tested our tires on smooth pavement at 29.5 km/h (18.3 mph), and found no speed difference between narrow and wide tires. If you ride much faster, then it’s possible that wider tires roll a little slower, but the difference will be so small that it’ll get lost in all the other factors that influence your bike’s speed. On the other hand, if you ride slower, then the advantage of wider tires will be even greater.

Spinning up

Wider tires are a little heavier than narrow ones. The difference is smaller than many cyclists imagine – air doesn’t weigh anything – but a wide tire has a little more rubber and casing. Won’t this make the wider tires harder to accelerate? The answer is “No.” The reason is simple: Bicycles don’t accelerate very quickly. Even a professional bike racer’s power-to-weight ratio is far less than that of the slowest economy cars, and those don’t exactly push you back in the seat when you floor the throttle. Bikes don’t accelerate fast enough for small changes in wheel weight to make a difference. That is why professional sprinters can use relatively large wheels (which inherently are heavier) and still win races.

The UCI requires a minimum wheel size of 55 cm, yet racers use 700C wheels that are 10 cm larger than required. If wheel weight mattered as much as most cyclists imagine, then pros using the smallest wheels would win every race. And yet, even though many have tried smaller wheels, all have returned to 700C wheels – probably because the larger wheels handle better due to their optimized rotational inertia. (But that is a topic for another post.)

Conclusion

What this means for us riders is that we can choose our tire width freely, without having to worry about performance. Of course, this doesn’t mean that a wide ‘touring’ tire will perform as well as a narrow ‘racing’ tire. Casing performance determines 95% of a road tire’s speed, and to get good performance, you need a supple high-performance casing. (The other 5% come from the thickness of the tread.)

Tire width influences the feel of the bike, but not its speed. If you like the buzzy, connected-to-the-road feel of a racing bike, choose narrower tires. If you want superior cornering grip and the ability to go fast even when the roads get rough, choose wider tires.

Further reading:

Posted in Testing and Tech, Tires | 53 Comments

Happy New Year!

All of us at Compass Cycles and Bicycle Quarterly wish you a Happy New Year and many great rides for 2018.

Posted in Uncategorized

Past Year of Bicycle Quarterly

“What? I have to wait three months for another Bicycle Quarterly?” In various forms, we hear this comment quite often. New subscribers enjoy their first issue, and they want more. Yet as a quarterly publication, BQ appears only every three months. That is how long it takes to put together another issue – with a more frequent schedule, it would simply be impossible to maintain the high quality with our small staff.

However, there is a solution to the problem: One of our most popular products is the ‘Past Year of Bicycle Quarterly,’ which consists of the last four issues before the current one. The articles in BQ are timeless, and this is an excellent way to catch up on the great adventures, technical articles, and historical features that preceded your first issue. The BQ’s of the last year have been an especially good ‘crop.’ Read on for some of the highlights.

My own favorite is the incredible ride across Kurakake Pass in Japan. Imagine a spectacular road up a perfect mountain pass, abandoned many years ago. We were told that it had been rideable 20 years ago, but would we still be able to get through? We knew it would be an adventure, but we got a little more than we bargained for.

For years, I’ve searched for an elusive passage across the Sawtooth Ridge in the Cascade Range of Washington. My most recent attempt came as the first winter snow began to make the high roads impassable. I had checked maps and satellite images, and the forest road I wanted to take seemed rideable. But things don’t always turn out as planned!

Join us as we take a Moots Routt to Bon Jon Pass. What seems like an easy ride on the longest day of the year turns into a race against the fading daylight. The Moots performs great, but will it be enough to beat the setting sun?

We ride the Open U.P. up (and down) the highest paved pass in Japan. We came here to test how a modern race bike with ultra-wide tires handles some of the most challenging paved and gravel roads on the planet. In addition to pushing the bike to its limits, we discover a magical landscape and a wonderful mountaintop hut where we spend the night.

Matt Bryant takes you on a ‘packbiking’ adventure around Mount Baker – combining road riding with portaging bikes on unmaintained mountain trails for a true adventure that pushes the limits of what we could even imagine.

Renowned constructeur Peter Weigle tells the story of building a superlight bike for the Concours de Machines

…and riding on small mountain roads in Japan. He provides a unique perspective about taking part in these ‘BQ adventures.’

Bicycle Quarterly brings you stories you won’t find anywhere else. Daniel and Madeleine Provot’s life revolved around cyclotouring in mid-century France, and their story has inspired us and many of our readers as we enjoy our cycling.

We take you right into the action as we visit the makers of the bikes and components we enjoy: Panaracer’s tire factory (above);…

…Gilles Berthoud in France, who make beautiful bags and leather saddles (above); Paul Components in Chico, CA;…

…and Schmidt Maschinenbau in Germany, makers of the SON generator hubs and Edelux headlights (above, one of Schmidt’s testing tools).

We continue our famous technical research that has shaken up the bike industry: How wide can tires get before their performance drops off? We test tires from 32 to 54 mm under closely controlled conditions to bring you the answer.

Stunning studio photos of modern and classic bikes round off each issue, but of course, there is much, much more.

Like the ride through the mountains near Cuernavaca in Mexico, and… There is really no way to do a whole year of Bicycle Quarterly justice in a single blog post – with close to 100 pages of content, each issue is more like a book than just a magazine.

If you already have some of these back issues, you can customize your own 4-Pack and select the Bicycle Quarterlies you want to read – check our full table of contents that also includes photos from every Bicycle Quarterly.

Order your ‘Past Year of BQ’ today and enjoy many hours of reading as you dream up your own adventures.

Photo credits: Isabel Uriarte (Photo 3), Matt Bryant (Photo 6), Rob van Driel (Photo 7), Duncan Smith (Photo 14), Natsuko Hirose (Photos 2, 5, 8, 11).

Posted in Bicycle Quarterly Back Issues | 4 Comments

Happy Holidays!

All of us at Compass Cycles and Bicycle Quarterly wish you Happy Holidays!

Posted in Uncategorized | 3 Comments

Around the Coastline of Britain – Interview with Andrew Mathias

The top of Bealach na Ba Pass

This autumn, Andrew Mathias rode around the entire coastline of Britain in one setting. Many of us followed his beautiful journey on Instagram. Now I had the opportunity to interview Andrew about his epic journey.

JH: Congratulations on riding around the coastline of Britain. It was fun to
follow you on Instagram. You rode 5000 miles (8000 km) in 64 days?

AM: Thanks very much, and I’m glad you enjoyed following the journey. I really enjoyed updating and creating a small mini log via Instagram. I rode 5,000 miles in 61 days. The original plan was to do the ride in 64 days, however, I finished ahead of schedule.

At the start of the 5000-mile ride

JH: How did you get the idea for this ride?

AM: For a long time, I’ve wanted to explore several areas of the UK coastline on two wheels, especially the west coast and the islands off the shore of Scotland. As I delved into planning and research, highlighting places I wanted to visit, it soon became clear that it was an option to do the whole coastline in one go. Once the idea entered my head it was always going to happen!

JH: Did you ride every day? No rest days?

AM: Yes, I rode for 61 consecutive days. I had multiple chances to have a day off, however, with no pain or injuries, and wanting to keep the momentum going, I just kept plodding on.

The first night at Aberystwyth

JH: And you did it self-supported! Where did you sleep?

AM: Yes, I rode solo for the entire tour and was self-supported. I camped using a tent I carried for most of the first month. A few areas were close to friends, so I stayed with them. I used hostels/bunkhouses and some bed & breakfasts. I also used Warm Showers, which is basically the bike-touring equivalent of couch surfing. I met many interesting, like-minded people this way.

Portpatrick Stranraer

JH: I really enjoyed your photos. I realize that riding along the coast, you
had plenty of great views, but I still was amazed by the beauty of your
shots.

AM: Thanks, I loved stopping to take photos! If I had stopped every time I wanted to take one, then I’d still be on the road! I knew there would be spectacular scenery in places, however, I was genuinely amazed almost daily at how underestimated the UK is in terms of beauty. I am massively lucky to have had the opportunity to undertake this journey.

Lake District

JH: It seems that the weather was OK despite your riding in late autumn?

AM: October and November worked best for me in terms of taking time away from work. However, it’s very nearly the worst time of year to do this ride. I was incredibly lucky with the weather. It was a risk for sure, but I’m a big believer in the statement “There’s no such thing as bad weather, just bad kit.” Having only had around six days of constant rain, I can’t complain whatsoever!

Helmsdale

JH: What did you carry on the bike?

AM: The main items were a few pairs of bib shorts, a few jerseys, rain jacket and wet-weather gear, tent, mattress, limited casual clothing, spares and tools. I tried to pack very minimally and include things only if they could be used for multiple purposes. Anything I needed en route I could buy, and anything surplus to requirements could be left behind.

Harbour town of Kippford

JH: Did you get your bike and equipment for this ride, or did you just ride
a bike you had?

AM: I spec’d the bike specifically for long days in the saddle with lots of miles. It was built with touring in mind, however, the frame that Triton Bikes and Cloud9 Cycles built is super-versatile, meaning that, with small changes, I can use it for pretty much anything. I’m now making the change to ultra-endurance race events; the bike will also be perfect for this, too. I bought the Apidura bags specifically for the journey and was massively happy with the way they performed.

JH: Any equipment trouble?

AM: One of my tent poles snapped a few days in. Not ideal, but I was able to improvise. Apart from that, I was extremely lucky with how the bike and my setup performed.

John O’Groats at the northeastern edge of Britain

JH: You rode Compass tires. How did they perform for you?

AM: This was the first time I used Compass tyres. In fact, it was the first time I ran anything larger than 28 mm tyres on the road. I went for the 35 mm Bon Jon Pass tyres and set them up tubeless. Within 20 miles I had already fallen in love with how comfortable I was. The low rolling resistance was a big asset: They were super quick once momentum had been gained. The grip was great in both dry and wet conditions. I ran around 4.5 bar (65 psi) front and rear, and I experienced only a minimal drop in pressure overnight. I covered around 2,500 miles (4000 km) before getting my first puncture! I was carrying a new spare which I changed over to shortly after this. I picked up a few more punctures before the end. However, I was massively happy with the way they performed, so much so that I will continue to use them for definite. I will find it very hard to go back to anything smaller than 35 mm tyres, especially with races next year totalling over 200 miles (320 km) a day… Comfort is key!

The bottom of Bealach na Ba Pass

JH: Tell us about some highlights of your ride!

AM: There were many highs as well as many lows, all adding up to create an incredible journey. My biggest highlight was Bealach na Ba Pass. This is a renowned climb in the Scottish Highlands. It takes you through the mountains of the Applecross Peninsula. A hurricane was forecast for the day I reached the pass. The wind was strengthening as I a approached Applecross, but the scenery was spectacular. I was lucky to get clear skies, so I could enjoy jaw-dropping views during the ascent. The climb itself is around 6% average for 3-4 miles, followed by four 20% switchbacks at the summit. I felt a massive sense of relief and achievement before enjoying a hugely fast descent.

Approaching Applecross during a hurricane

JH: And what were the hardest parts?

AM: As well as being a highlight, Applecross was also the hardest physical day on the bike. The fact it was so difficult made it even more of a highlight. From a mental point of view, keeping morale and motivation high was difficult. Taking every day as it comes is all you can do. Enjoy your surroundings, and the freedom that your bike gives you, and the mind will look after itself.

At the westernmost point of the ride

JH: If you were to do it again, what would you do differently?

AM: The obvious answer is to do it in the summer! However, doing it in the cold, wet and, at times, dark conditions added to the challenge. Seeing areas like west Scotland in its raw and rough state was something that I will never forget!

JH: I was glad to see that just after finishing your great ride, you already
were back on your bike. Any plans for another big adventure?

On the white cliffs of Dover – almost at the finish!

AM: For sure! I was out and about the day after finishing, and have been a fair bit since. I’m currently training for the TransAtlanticWay, which is an ultra-endurance race in Ireland next year. However, I want to explore Europe for six months or more by bike. That is also in the pipeline!

JH: Good luck on those endeavors. I look forward to hearing and them!

You can see all of Andrew’s photos from his trip on his Instagram feed at mathias0487.

Posted in Rides | 1 Comment

René Herse: The Beauty of Function

At Compass Cycles, we have taken much of our inspiration from René Herse and his legendary bikes. In the past, we’ve talked about the great performance and incredible reliability of Herse’s bikes, but what is even more striking is their beauty. You notice it immediately when you look at one of his bikes, or even a photo… but it took much study to unlock the secrets of the ‘magician of Levallois.’ (Levallois was the suburb of Paris where Herse made his bikes.)

Herse’s bikes don’t derive their beauty from complex lug shapes, but from their simplicity. It was Hiroshi Hagiwara, the maker of the Japanese Alps bicycles, who said in a recent Bicycle Quarterly interview: “A bicycle is a frame with two wheels. Everything else is a distraction.” When I thought about this while looking at a René Herse bike, I realized that Herse’s genius was to turn these distractions into assets that make the bike more beautiful.

The most obvious one are the fenders (above): They follow the outline of the wheel so gracefully that they enhance the bike to the point where the same bike without fenders would look naked.

Herse masterfully joined the frame and wheels: Herse’s custom-made dropouts place the wheel centers in the prolongation of the stays and fork blades. That way, the wheels are centered in the end points of the frame, which ties the whole bike together. As an added benefit, this allows the dropouts to be smaller, stiffer and lighter.

Other things are harder to notice: The two arms of the custom-made hanger for the Cyclo derailleur line up perfectly behind each other. This is very difficult to do, since the chainstays are angled upward and outward, and the two arms have to be bent very precisely to very different curves. It adds to the beauty of the bike, even if it’s not immediately apparent.

The brake cables are truly parallel to the head tube and seatstays. That way, they don’t distract from the frame, but underline the straightness of the tubes.

Herse considered the proportions of the frame beyond the simple question of frame fit. The tandem we rode in France last summer has twin lateral stays, but they don’t just line up whichever way. Herse subtly adjusted the frame’s dimensions so that the lateral stays are parallel, and the balanced sizes of triangles they form further adds to the attractiveness of the frame.

Herse’s genius was to achieve this with bikes that also fit their riders perfectly. Because all this magic wouldn’t mean much if it detracted from the ride.

The opposite is the case. For René Herse bikes, the old adage that “What looks right usually is right” really holds true. His bikes and tandems ride wonderfully.

The beauty of Herse’s bikes makes it easy to forget that they were not intended as showpieces – they were designed to be ridden hard. Herse’s background reveals much about his thinking: He worked on prototype aircraft before he started making bicycle components and then bicycles. His aircraft experience shows in details like the custom screws: During the early 20th century, there were no universal specifications for bolts. Airplane makers made their own bolts, and to make sure that only correct bolts were used, each maker gave their bolt heads a distinctive shape. That way, a mechanic could immediately see if a bolt had been replaced with an incorrect one of suspicious quality. René Herse’s distinctive bolts for stems and seatpost binder have triangular heads that trace their origins to this practice.

Elegance and function also are combined in his lighting systems. The most important part of the photo above is what you don’t see: lighting wires. They run inside the rack, inside the fenders, and inside the frame tubes. Even where the current needs to be transmitted from the fork to the frame, there is no external wire: An insulated carbon brush on the steerer tube mates with an insulated brass ring inside the head tube, transmitting the current while allowing the fork to turn freely. Eliminating exposed wires not only is more elegant, but it also reduces the risk of wires getting snagged or breaking from being moved time and again.

The beauty of René Herse goes beyond the frames. After all, Herse started as a maker of components, and only began making complete bikes during World War II, perhaps because it was difficult to sell components without bikes onto which to put them. Herse’s components, whether his brakes (above), cranks or stems, combined superlight weight with superb performance.

Often overlooked are small details, like his double-ended bolts for attaching the rack to the brake pivots. Many builder simply use the brake bolt to hold the rack tab as well, but this brings the risk that the bolt works loose. Herse’s solution is more elegant: His brake bolt has a forward extension onto which the rack mounts with a nut. It will never work loose. You’d expect no less from an airplane builder: If a bolt loosens in mid-air, you can’t just stop and tighten it!

Despite all their elegance, René Herse’s bikes have a certain handmade quality. It’s obvious that the lugs and stem were shaped by hand. A lot of modern builders make bikes that look more crisp and uniform. At first, I thought that this was because René Herse bikes were made in significant numbers – up to 350 left the workshop during the best years – and corners had to be cut. But René Herse’s hand-lettered logo indicates that the handmade aesthetic was intentional. Herse could easily have ordered decals, but instead, every frame was hand-lettered by a sign painter. Like great pottery, Herse’s bikes look handmade without appearing crude or unfinished. In my opinion, that makes them works of art.

For the complete story of René Herse, his bikes and their riders, read our 424-page book on the ‘magician of Levallois,’ lavishly illustrated with studio photos of his bikes and historic photos from the Herse family archives. We still have a few copies of the Limited Edition (with a slipcase and art prints of four unpublished photographs from the René Herse Archives), or the ‘standard’ edition at a more affordable price (also available in French). Click here for more information.

Two of my favorite images from the book are available as large-format, ready-to-frame Limited Edition posters. Hang them on your wall and be inspired every time you look at them. Click here to order our set.

And if you haven’t seen our video of a René Herse tandem in action, click here.

Posted in books, Rene Herse cranks | 23 Comments

New SON Generator Hubs!

We are excited to announce the latest SON generator hubs. The biggest news is the connector-less SL system for thru-axle hubs: Now you can remove your front wheel and its generator hub without having to disconnect any wires, even with a thru axle.

The system consists of three parts: The heart is the SONdelux 12 generator hub. The SONdelux is the lightest generator hub in Schmidt’s program, and it has the least resistance, so it was a natural choice for this application.  The flanges are spaced as far apart as possible while still leaving room for the disc rotor and caliper.

This hub has proven itself for many thousands of miles. What’s new is the lack of external connectors for the lighting wires. The current is transmitted via the axle (positive) and an insulated ring that is pressed onto the axle (negative). Like its counterpart with external connectors, the connector-less SL hub is available in black or silver.

The hub mates to a special dropout. By the way, the machining traces that form the funky pattern in the photos can be removed by your framebuilder. Above you see the outside, which looks like a standard stainless steel dropout for 12 mm thru-axles (12 x 1.5 mm thread).

It gets more interesting on the inside, where one dropout has a recess…

… into which an insulated contact plate fits. As you install the hub, the axle connects to the dropout for the positive contact, while the insulated ring on the hub mates to the dropout’s contact plate, which is insulated as well. A wire goes inside the fork leg from the contact plate through to the lights. That way, you provide a path for the current to flow from the hub to the light without any exposed wires that can get snagged or break from repeated flexing during installation and removal of the front wheel.

We have a small number of contact plates and dropouts in stock, with more to come once production catches up with demand. And of course, the connector-less SL system has been available for non-disc hubs all along, and we have those components in stock, too.

That isn’t all the generator hub news! Many modern rear hubs are black, and we are now offering SON hubs and lights in black to match. We’ve worked with Schmidt Maschinenbau to make our favorite hub, the SONdelux Wide-Body, in black, too. The black hub is available in the standard and connector-less SL versions, with 32 holes. This is a one-time production run, so quantities are limited. If there is sufficient demand, Schmidt will make more for us, and in other spoke counts, too.

We also have the SONdelux Centerlock Disc for quick release forks in black…

… and the Edelux II headlight for hanging mounting. (We’ve been stocking the ‘standing’ Edelux II in black all along.) Now you can choose between silver and black components when equipping your bike with the best and most reliable generator lighting.

All these products are in stock now. For more information or to order, click here for hubs and here for lights.

Posted in hubs/rims, Lighting | 8 Comments