Experiencing Suspension Losses

reiter_road

Suspension losses cause a significant resistance when riding your bike. We knew this from our testing, but it was illustrated in a powerful way during a 300 km brevet a few years ago.

My friend Ryan and I rode in a group of about 10 randonneurs. Everybody was taking equal pulls at the front, until we got to a particularly rough road. It wasn’t chipseal, but an old road surface where the asphalt had eroded away over time between the aggregate. It was hard for us not to miss the fact that the rough road caused more resistance. Even though the gradient hadn’t changed, you could hear one rider after another shift to an easier gear. The pulls at the front became shorter as riders were trying to maintain the group’s speed.

One rider curiously seemed unaffected by the surface change. Ryan was riding his randonneur bike with 650B x 42 mm Grand Bois Hetre tires. He was in the same gear as before, and his pulls at the front remained at the same speed as they had been on the smooth pavement. You could hear the other riders grunting and breathing harder when Ryan got to the front, and he isn’t usually a rider who forces the pace. Fortunately for the rest of us, after a few miles, the rough pavement ended. Ryan was back to normal, since his pulls now were at the same speed as everybody else’s.

I was riding Grand Bois 700C x 32 mm tires during that brevet, which most cyclists would consider ample for paved rides. Yet the difference in speed to the 42 mm tires was remarkable. The difference in comfort was no less remarkable. At the finish, I told Ryan: “That section of rough pavement along the Skagit River was really punishing.” He looked at me a bit incredulously and replied: “I never noticed it.”

Further reading: A blog post explaining suspension losses, how we measured them, and approaches to minimize them.

About Jan Heine, Editor, Bicycle Quarterly

I love cycling and bicycles, especially those that take us off the beaten path. I edit Bicycle Quarterly magazine, and occasionally write for other publications. One of our companies, Bicycle Quarterly Press publishes cycling books, while Compass Bicycles Ltd. makes and distributes high-quality bicycle components for real-world riders.
This entry was posted in Testing and Tech, Tires. Bookmark the permalink.

47 Responses to Experiencing Suspension Losses

  1. David Pearce says:

    Interesting! I do believe those are the tires I bought from Compass Bicycles. Grand Bois Hetres, 650B x 42 mm.

    Gotta get that bike built! Looking forward to it. Roll on!

  2. Rod Bruckdorfer says:

    I agree with you completely about the 42 mm x 650B Grand Bois Hetre tires. My Boulder Brevet is fitted with these tires. I mounted them tubeless. My weight is about 150 lb. Front tire pressure is 40-45 psi and the pressure in the rear tire is 45-50 psi. The tires are supple and very fast. On our ride last weekend, the Tour de Talbot (Maryland) we came across a long stretch of chipseal that was perhaps two months old. A small group of riders on carbon fiber and aluminum bikes eased by us. Their hands were visibly vibrating on the handlebars, whereas, my hands were very comfortable and vibration free. Later, my lovely wife and riding partner told me her hands were also suffering from the road vibration, whereas the chipseal had no effect on my hands. Lenora rides an aluminum/carbon fiber bike with 23/25mm 700C tires (carbon fork and seat stays). Pedal effort also remained unchanged. I can not say enough good things about these wide tires and the Boulder Brevet.

  3. Karel Boonen says:

    Ryan was just bragging! ;-)

  4. PTD says:

    I appreciate these more personal or real world explanations of the types of bikes you like. This adds more meaning to the technical articles you produce.

    • marmotte27 says:

      And the other way round, the tests add meaning to the real world riding by showing why things happen the way they do. You no longer go: ‘I must be a crap cyclist cause I don’t feel well on this super stiff carbon bike with skinny tires when everybody tells me this is the pinnacle of bike technology’

      • Both are important. The repeatable scientific tests are crucial to validate the on-the-road experiences. Otherwise, we might be confounding variables and come to erroneous conclusions, just like cyclists have for decades when they concluded that narrow tires at high pressures were faster.

        On the other hand, testing without the on-the-road experience often isn’t very useful either. Bicycles and their riders form a complex system that isn’t easily translated into single variables, and if you test the wrong variables or use the wrong model (such as a tire test on a steel drum), you will get erroneous results.

  5. Steve Palincsar says:

    And this is the same Ryan who, a few years earlier, wrote in a sidebar to a BQ test, that those 42mm tires were overkill? :-)

    • Yes, it’s the same Ryan. When he started riding with us, he was very proud of his carbon racing bike with 23 mm tires. Even when he bought his 650B bike, he intended it to be for long brevets and off-pavement rides only. In the end, he’s only ridden the carbon bike twice since he got his 650B randonneur about 3 years ago…

      • David Pearce says:

        Wow. Interesting.

      • Rod Bruckdorfer says:

        I can understand why Ryan changed his mind. My Boulder Brevet with its 42 mm X 650B tires is the only bike I want to ride. Prior to the Brevet, I rode a 1987 Miyata 1000 LT touring bike, which I purchased new in 89 and built-up with Phil Wood hubs. It hangs in the basement unused.

  6. Lyle F. Bogart says:

    So, Jan, when can we expect a nice, supple 700×42? I love my Schwalbe Marathon Pluses for their indestructibility but I wouldn’t call them light and supple. . . :^)

    • When the time comes for new tire projects, we’ll consider your request together with all the others we get.

    • Oliver says:

      You should definitely try Marathon Supremes. Less than half the weight of your Marathon Plus, a hundred times safer on wet pavement, and a thousand times more comfortable.

    • Christophe says:

      If you are looking for comfort, Marathon Pluses are possibly the worst tires you can find. They are extremely heavy (more than 1kg per 700C-40 tire), dangerous on wet pavement, and very uncomfortable for the size. The same company produces for example the Marathon Supremes, that weigh 495g per tire in size 700C-42, are much safer and comfortable.
      And anyway, more comfortable than Marathon Pluses is not hard to find…

      • Lyle F. Bogart says:

        The pluses are certainly heavy–the problem–but I initially got them for puncture resistance when I was living in goat-head country on the Navajo Rez. Many thousands of miles on and off road and never a flat! But, those aren’t the conditions in which I ride ar this time…
        It’s interesting: you’re the second person to note how dangerous the pluses are in the wet. I haven’t experienced that, even here in the wet PNW. I will be trying the Supremes, though, thanks to your recommendation and that of others! Thanks!

      • You have to consider the German cycling market when looking at tires from Schwalbe and Conti. There, you either are an enthusiast on a racing bikes, with 23 or a maximum of 25 mm tire. Or you are a commuter on a beater who rides 1-2 miles to the train station. If they have a flat, they miss their train. Even the high-end touring bikes are far from the performance-oriented machines we know in the U.S. – witness the Tout Terrain we tested a few years ago. So German high-performance tires are narrow, and wide tires are more about puncture-resistance than comfort and speed.

        In the U.S., there are enthusiasts who commute long distances, ride brevets on classic randonneur bieks, or ride on mixed surfaces. This means that there is a real need for a wide, supple high-performance tire. Even here, this is a small market, which is why the big makers aren’t keen on supplying tires for it.

    • John Duval says:

      Punctures vs performance is a real conundrum. I ran marathon racers 35-622 for about 3 weeks after too many flats on my 32mm Cypres tires. My speeds dropped 15% and the ride was terrible. I now run 32mm Extra Leger with tire wiper in the rear only. I get flats a couple times a month on the front from goats heads and glass (often two holes at a time), but rarely flat the rear (last one was a defective tube).

      My next experiment will be sealants. Tire wiper is too noisy and fussy. I don’t recall reading about sealants here. Sounds promising, but we shall see about performance. I understand triathletes use it.

      • I think sealants have a huge potential. Tubeless technology also seems promising. Some of us at Bicycle Quarterly have been experimenting with it on our own bikes…

        We are lucky that where we ride, whether in urban or rural environments, flats are relatively rare. But then, Seattle isn’t goathead country!

        last one was a defective tube

        I gave up on the inexpensive tubes that most bike shops sell after having too many failures, including two at Paris-Brest-Paris. I now use the Schwalbe tubes we also sell, and haven’t had a defective tube since.

      • I installed my Hetre tires without tubes using Stan’s Notube rim tape and sealant. I have a friend who does a daily 50 mile commute along a road littered with glass, fastening, etc. etc. After he setup his tires tubeless, he has very few flats. The most recent flat was caused by a 3″ nail penetrating the tread and sidewall. I am installing Hutchinson Sector 28 tires (tubeless) on my wife’s bike. I believe tubeless tires will become mainstream on road bikes in the next few years.

      • John Duval says:

        My failed tube was a schwalbe extra light, though I still do not question their exceptional quality. I had just checked it for leaks the night before by running the tube thru water, reinstalled it, and it was flat the next morning. Another run thru water showed two tiny leaks at the outer edge of the valve stem reinforcement. It is an odd mode of failure, so I checked the rim and tire bead carefully and found nothing. An anomaly. No problems since.

      • Check your rim to make sure there aren’t sharp edges around the valve hole. With a superlight tube, you need a smooth edge even more than with a standard tube.

  7. Joel Niemi says:

    The south-side Skagit road has to be one of the roughest paved roads north of Seattle. 5 or so years ago a few of us stopped at a store east of Mt. Vernon, and the cashier asked us where we were headed at 8:00 in the morning. When we told him, he said “good luck – we don’t usually take our motorcycles on it due to the paving quality!” 700x23C were very tiring on it

  8. Larry T. says:

    I’ll probably never go as far as 650 – 42 but this summer after returning from the nice roads of Italy to the frost-heaves of Iowa again, I decided life is too short to ride around on skinny (23 mm) tires and upgraded my bikes to some fatter rubber, including a set or GB “Cerf” in the mix along with Challenge Strada and Vittoria CX 25’s. I’m now experimenting with how low I can run the pressures but still avoid pinch flats…but life IS too short for skinny tires…I’ll be riding the fattest things that’ll fit on my bikes from now on!

  9. David Pearce says:

    You mentioned in another post that on one of your bikes you use a lever to shift the front derailleur. I don’t doubt you do it, but I can’t figure out how! Reach between (?) your legs to shift while you’re pedaling? I suppose the lever moves laterally? Can you mention a previous BQ I could order where these classic shifters are discussed? I’ll tell you, I’d love to see a video!

  10. thebvo says:

    It’s all the more reason to test other wide tires!
    I spend all day dreaming about a 650B “ideal” bicycle because, among other reasons, it would use the mythical Hetres, but what about my current (700c) bike? Can’t it also benefit from wide (38cm+) supple tires? I know that there are wide tires available in that size, but many have gone untested by BQ. I find your tests enormously helpful and unbiased, but the number of wide tires you’ve tested leaves a few important holes. Of the 700c tires you tested 15 of 19 were skinnier than the Grand Bois cypres(32). The Vittoria Voyager Hyper, Schwalbe Kojak, Marathon Racer in a wide size (up to 40) or a Marathon Supreme come to mind.
    Furthermore, it’s a wonder why so many tires that were tested were so skinny considering BQ’s penchant for wide tires.
    It’s something to consider for the next tire test. Maybe you’ll test the Extra Leger tires against the regular GB tires.
    The new issue is amazing! The color is poppin, and the new binding will stop the cover from falling off after being read/ referenced/ flipped through far too often. :)

    • After the first tests which served to establish benchmarks of tire performance, we tested only tires that had the potential to offer performance and comfort. Unfortunately, there aren’t really any wide 700C tires that fit the bill. It makes little sense to test tires with stiff sidewalls that weigh more than 500 g, and hope that they somehow magically perform well.

      In some cases, we tested narrower versions of the tires you mention, but unless the manufacturer changes the casing from one width to another (which almost none do), then the performance of the wider versions will be very similar – our testing showed that on smooth roads, tire width doesn’t really affect performance much.

      We do hope to test the Extra Leger tires against the regular Grand Bois tires, and also include a few recently introduced tires into the mix.

    • Benjamin Van Orsdol says:

      oh yea… The Compass 26″ tires too! How could I forget! Were they left out of the recent test due to the major conflict of interest?

      • No, we would have tested the Compass 26″ tires, but we didn’t have the means to test 26″ wheels in that test. If anything, an objective test reduces conflict of interest, as it gives you actual numbers, rather than just impressions of “seems like I was riding in the next-larger gear than usual” or somesuch.

  11. Bruce Hodson says:

    After I burn through my Conti TourRides I’m looking at some of these alleged “smooth/supple” tyres. The 584mm x 42mm TourRides are abuse resistant for sure, but they don’t ride all that much better than the 622mm x 28mm tyres I was running before.

    So much for flat-protection being the way to go for mixed surface rides.

    • On gravel, I don’t get many flats – I cannot remember a single one. First, there is less debris, because there is less traffic. And second, the tire can push the debris into the ground, rather than the road pushing the debris into the tire. That is how cyclocross racers can ride extremely supple tubular tires without flatting.

      • David says:

        “I can’t remember a single one”

        I can! Doesn’t the test ride of the Calfee 650B bike in the most recent Bicycle Quarterly describe you getting a flat tire while riding on a gravel road with Grand Bois Hetre 650B-42 mm tires?

      • I should have written “punctures” instead of “flats” in the comment above. The flat on the Calfee was weird, because I couldn’t find a puncture in the tube when I removed it. There was nothing stuck in the tire, either. Perhaps it was a valve problem – it was an inexpensive tube, and they tend to have issues. I replaced the tube and threw the old one in the trash, not wanting to carry a bad tube for hundreds of kilometers just to examine the cause.

  12. Ian Bray says:

    This is a good slow motion film showing Paris Roubaix riders experiencing suspension losses on the pave and how their tyres act as suspension, up to a point.

    • That is an impressive video. However, suspension losses are caused mostly by smaller vibrations that occur at higher frequencies – what cyclists often call “road buzz.” It turns out that the discomfort you experience is caused by your body’s tissues rubbing against each other, which creates friction and absorbs energy, thus slowing you down.

      • marmotte27 says:

        Is that what they said in the US arme study on tank seats? Surely both kinds of vibrations play a role? When I was working in my basement with a jackhammer the vibrations were of the big kind too, and I started sweating heavily after only a few moments.

      • Yes, the U.S. Army study found that energy absorption due to vibrations was directly related to discomfort. Yes, a jackhammer will do the job, too, because the vibrations have a relatively high frequency.

        What surprised us is that suspension losses are important even on smooth roads. When we tested them on both rough and smooth roads, we found that a very stiff fork made the bike slower even on newly-laid, ultra-smooth pavement. The difference wasn’t huge, but it was statistically significant.

  13. marmotte27 says:

    But shouldn’t the rumble strips in your test be very much akin to the paves of Paris-Roubaix?

    • Yes, cobblestones at high speeds are about the same frequency as the rumble strips we tested, even if the amplitude of the rumble strips is lower than that of the cobbles you find on Paris-Roubaix. The video, with its slow motion, emphasizes the occasional big bumps, rather than the high-frequency vibrations.

  14. Rafal says:

    And what about Schwalbe Super Moto 60-622? There is probably the fastest wide tire on the market with the lowest vibrations. Could you test it?

    There are some interesting data from the tire 60-559:

    http://wimschermer.blogspot.com/2012/11/anti-lek-strategie-met-super-moto-en.html

    but 29” version (60-622) would be even more interesting.

  15. Sukho V says:

    Just experienced a similar situation this weekend on a long ride through northern california wine country’s back roads. These roads consist of long stretches of crumbling old pavement with varying degrees of patchwork and some good ol’ fashioned potholes that would buck you off your bike if you weren’t paying attention. My friend was on his Hetres, me on 28mm Pasela’s. You can guess who hardly noticed that the road was bad. I can attest that the 28mm Pasela’s were not enough. We passed by a lady on an aluminum road bike with 23mm tires and actually heard her saying she wished she had “shocks” on her bike.

Comments are closed.