Tyre widths

robmanic1

So whats the deal with road tyre widths? What are the advantages/ disadvantages with 20mm over 25mm etc? Is it a comfort and control type thing or more to do with rolling resistance and grip?

CrookedCucumber

All the above.

If you want to go as fast as possible in what is predominantly a straight line on dry roads, and you don't care about comfort in the saddle, you need the thinnest wheels and slickest tyres that the road conditions (and your weight) will allow. But fatter tyres will grip better, and be more comfortable, particularly on yucky surfaces, and can be run at a lower pressure, further increasing grip.

Since I don't care very much about speed, I prefer fatter tyres even for road use. They seem (to me at least) more stable in, say, patches of gravel, and I'm less concerned about bumping over the occasional pot-hole. But I draw the line at running mountain-bike tyres on the road, because I do want to get there eventually

redddraggon

23mm or 25mm are the best bets. 20mm is too narrow for real road riding, and 28mm tyres won't fit in a lot of "race" frames.

robmanic1

Thanks for the replies, chaps. I've just bought a set of 20's (note to self; seek advise BEFORE buying), will they be junk or just a bit skittish?

redddraggon

Robmanic1 wrote:

Thanks for the replies, chaps. I've just bought a set of 20's (note to self; seek advise BEFORE buying), will they be junk or just a bit skittish?

You'll have to pump them up above 120psi to avoid pinch flats which means you'll get a harsher ride. The rolling resistance probably won't be any better than the like 23mm version of the likes of PR2s or GP4000s.

They'll probably be fine, but I wouldn't recommend using them on a poorly surfaced road.

CrookedCucumber

And, in any event, you'd need to be an Olympic-class cyclist before you noticed an advantage in 20mm tyres, as compared to 23mm or 25mm, no?

robmanic1

I'm in luck then!

roger_merriman

i have some 20mm training tires on my old 10 speed, thus far no pinch flats even at 110 psi at the most, the old steel frame is quite flexible old thing so take a fair bit of the knocks and having learnt my trade off road with out suspention i probably do ride fairly light.