Wider Tires Are Faster (PDF)

In theory, wider tires offer better performance. Their contact patch is wider and shorter, thus requiring less tire deformation as the wheel rotates. However, the casings of wider tires en- dure greater stresses, and a wider tire requires a sturdier, less supple casing. Such a casing requires more energy to deform, and the net result often is a tire that is slower.

An alternative to sturdier casings is running the wider tires at lower pres- sures. This solution has been adopted by some track riders, who run their 25 mm tires at 10 bar (150 psi) instead of the 14 bar (200 psi) used for narrower track tires. Our real-road tests have confirmed that very high pressures offer no significant performance ben- efits.3 However, harder tires feel faster, probably because they transmit a higher frequency of vibrations, which riders associate with higher speeds.4 This appears to be the reason why performance riders have gravitated toward narrower tires time and again over the history of the bicycle.

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