Different width tyres

My alloy/carbon road bike has 23mm tyres. I’d like to fit something wider, having switched from 23mm to 28mm on another bike, with noticeable improvements to comfort and rolling. But although I have room for 25mm on the front, there is very little clearance under the seat stay bridge. Would there be any advantage in having a 25mm on the front? I suspect it would be better the other way round but that won’t work. Would there be any disadvantage in having odd tyre sizes?

Edward Holt

The obvious place to put a fatter tyre, if using two different sizes, would indeed be at the back, since bicycle weight distribution is heavily biased to the rear. That said, the advantages to running a fatter front tyre, in terms of grip and comfort, are not negated by having a narrower rear and it can be argued that, if more of either is needed, it is more useful at the front end. After all, hardtail mountain bikes with a suspension fork are a commonplace, unlike the alternative arrangement.

Richard Hallett

​​Cycle’s Technical Editor

This Q&A was published in 'Cycle' the magazine for members of Cycling UK. To contact the experts, email your technical, health, legal or policy questions to editor@cyclinguk.org or write to Cycle Q&A, PO Box 313, Scarborough, YO12 6WZ