Lennard Zinn and Marginal Gains
If you are a student of cycling — and the fact that you listen to this show means you are — you have no doubt read a fair amount of Lennard Zinn’s work, from books to being the tech editor at VeloNews, Zinn has written thousands of pages about cycling. And in this episode, he joins Josh to talk about his days as a skier, how he got talked into writing books, Hopf Bifurcation and bike shimmy, rolling resistance and Lennard's latest venture: E-bikes. We guarantee you’re going to love this thinking cyclists’ conversation.
Got a question you’d like to ask? Text or leave a voicemail at the Marginal Gains Hotline: +1-317-343-4506 or just leave a comment in this post!
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Hey Mark B. Great Question. The results from BRR roughly track in terms of x tire vs y tire. The pressure is another story. This is because the tests are done on a metal drum, not real riding surfaces. We are big fans of testing and it can be done pretty easily at home. Pick a stretch of road with no interruptions, ride at a power that is sustainable, and test at a few different pressures. You will quickly see how big of a difference it can make, and which pressure is optimal for that surface!
Recently I heard Josh say that his tire rolling resistance testing results roughly track with those from the Bicycle Rolling Resistance website (in contrast to the roll-down testing of a well-known randonneur). But for most tires BRR often shows rolling resistance going down as pressure increases, which would be the opposite of what I hear on the podcast. Could you help us understand how both Silca’s and BRR’s results can be true when they seem to point in different directions? Thanks for all of the great insights and fascinating thought experiments!
What is Josh’s take on latex tubes, on carbon rims, with rim brakes?
Hi Guys, love the podcast! Always enjoy how in-depth you get into the marginal gains. I have a tire question I was hoping Josh could answer on the next AJA podcast. I am wondering if a person is looking at two tires, say the Vittoria Corsa G+ 2.0 TLR and the Continental GP 5000 S TR, which have a rolling resistance at 100psi of 12.8W and 9.1W respectively, should you always pick the tire with the lower (steel drum) rolling resistance? Or do things like tire construction impact hysteresis enough to justify one tire over another? It seems that air pressure would have the biggest impact on hysteresis, but I figure it would be an interesting question to see if there are other factors to consider. It is a selfish question, because I really like the Vittoria tires on my mountain bike and would love to use the Corsa on my road bike, but I look at the rolling resistance numbers and always go with the GP 5000. Anyways, thanks again for the time you put into the podcast!
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