Jan Heine, the publisher of Bicycle Quarterly, has a blog called Off the Beaten Track. In his current post, he discusses a favorite subject of his: wider tires. The question is, how wide is too wide?
Heine has done research into tire width and performance. “It’s a well-established fact,” he writes, “that wider tires roll faster than narrow ones.”
When comparing 21 mm tires to 23s and 25s, he found the 25 mm tires are fastest of that group. Going up in size, he compared 26, 29 and 31 mm tires on a super-smooth asphalt road, and found no difference in their performance. The 31 mm tires were no faster than the 25s, but they weren’t slower, either. On rougher roads, the wider tires rolled faster.
There has to be a point at which the width of tires becomes a hindrance. If so, Heine hasn’t found one up to 42 mm tires, which he informally compared to 25s, and found the wider tires ran just as fast. Even 42s don’t appear to be too wide, he says. And wider tires than that just won’t fit most bikes.
So, if wide tires roll as fast, or sometimes, faster than narrower tires, why don’t more cyclists use them? They’ve got advantages besides speed. They give a smoother ride. They use lower pressures, so can resist flats better. They’re safer, because they’re less likely to be caught in a crack or a railroad track. And because they handle rough roads better, they might even encourage cyclists to ride roads that might be avoided with narrow, high pressure tires.
I run 25 mm tires on my bike. I prefer them to the 23s I used to run, mainly because they’re a little more comfortable. I inflate the front tire to around 95 psi, and the rear tire to a bit over 100. They are noticeably cushier than the 23s I had, which had much higher pressures.
I’d love to try wider tires, but the fork of my road bike is narrow at the top, and the 25s are probably the widest tires I can fit. As I look ahead to what my next bike might be (not that I’ll be buying a new bike anytime soon), I think I’ll find something that can take wider tires.
How about you? Do you run tires wider than, say, 25mm? How do you like them? Would you recommend them to other riders? Where is the advantage — speed, comfort, or flat resistance?