“Buy the nicest, most supple tires you can afford; and buy them in the widest width that you can fit in your frame.”
That is Joshua Poertner’s summary of a panel discussion on Cyclingtips.com. Joshua used to be the president of Zipp, the makers of super-fast aero wheels, and he did a lot of research on how to make your bike faster.
The panel included Joshua, cycling journalist James Huang, and me, with Elden Nelson (who runs the blog “The Fat Cyclist”) moderating. The goal was to explain the science behind the current trend toward wider tires to an audience of racers and performance riders, who want to understand how to make their bikes faster.
In the podcast, we talk about why narrow tires feel faster, but aren’t. We discuss how lower pressures increase the internal resistance as the tire flexes, but decrease the suspension losses from the vibrations of the bike – the two effects cancel each other, hence your speed doesn’t change.
We also talk about the history of this research. I was amazed to find out that Zipp had been doing similar research to our own. They were trying to optimize tire pressures for the professional racers they sponsored. During their testing on rough surfaces like the cobbles of Paris-Roubaix, lowering tire pressure made their racers faster – until their wheels broke. The next step was to go to wider tires, so the wheels could survive… And then they found that even on smooth roads, lower pressures and wider tires were faster. They considered these findings “trade secrets”, and yet the other teams just had to read Bicycle Quarterly to get the same information. And eventually they did…
To me, Joshua’s conclusion really is remarkable: “Buy the most supple and widest tire you can fit in your frame.” His words could just as well have been mine. To have the guy who designed wheels for Zipp say this… It shows that the wide tire revolution has reached cycling’s mainstream.