23mm or 25mm Tyres?

at a shade over 20st I use 23mm on my Ribble and have done without an issue for almost 4000 miles and my new Surosa has 25mm, the 25mm do feel a little better but I had a tank slapper on Friday in the wet, still dont know I i didnt lose it, I suspect that the type of tyres (23 are Armadilos and the 25's are Conti sport contacts) and not the size were the cause of the bambi syle sideways skid

FWIW I have been using Bontrager Race Lites for years in both 25 and 23mm versions.

I can't really notice any difference between them, though I use 25 on my audax bike and 23 on my road bike - more as an article of faith than anything else.

Overall though I think they are the best value tires around, for puncture protection v price v performance.

How narrow are your rims? Most "racing" rims are 14 - 15 mm inside width between flange beads, and in theory 28 mm tyres are the max. recommended width. In practice people run 35 mm cross tyres on them.

Frame and brake caliper clearance is more often an issue. Current Campagnolo brakes have worse clearance than SRAM or Shimano calipers.

Had two punctures in 100psi 25mm tyre (8 months apart).

Plenty of mileage but time for a change me thinks!
But will be opting for 23mm for summer.

why? Well I'm assuming less resistance but not much.
Might buy 25 or 28mm replacements for winter once I check the rim spec and spacing.

Dam just checked that 25's are the biggest I can squeeze on my rims.

Check rim size before choosing a tyre size folks!

If memory serves, in Mike Burrows' book on bicycle design he says there is no point in pumping a tyre up beyond 100PSI that it gives no appreciable performance gain.

This is my understanding, which is probably flawed:

On a flat surface, rolling resistance is supposedly lower with a wider tyre inflated to the same pressure since the contact patch is shorter and wider. ie: The tyre isn't distorted as much.

But with a rougher surface rolling resistance is lower if the tyre pressure is lower, since (maybe) the tyre soaks up the bumps and energy isn't wasted moving the axle up and down relative to the ground.

So it isn't a simple answer. You might say "all things being equal, then...", but things usually aren't equal. I have a feeling that lot of riders who are pumping their tyres up to 110 psi are only achieving less grip and giving their teeth a good rattle.

I read that Juan Antonio Flecha rode his 28 mm tubulars at 75 psi at Paris-Roubaix.

I have just put some Race X Lite Hardcase 25s on my SCR and I'm impressed. They're much better than the standard 350g Hardcase tyres. The postal scales says they weigh 255g each, which isn't too shabby and about the same as the Rubino Pro 2s I have used and liked (there's a new 150tpi version of those out now).

23 v 25mm isn't worth worrying about - about 15g. A colleague picked up some Schwalbe Durano 23s from the LBS. They look at least as wide as my 25mm Bontragers and sizing does vary across brands. I have read an explanation how rolling resistance isn't related to tyre width but can't remember why. Am not sure you'd notice any difference in comfort but the larger tyre volume will be better, all else being equal (in which case why not go for 28 or 32mm?).

I run 25mm tyres on everything except my TT bike. but then, I'm a big lad. like you.

In terms of rolling resistance there's no engineering reason why a 25mm tyre should be inferior. in fact, it's much easier to argue the opposite. What 25mm tyres are, however, is heavier. That's what'll slow you down. Not all of them mind: you'll probably find 25mm rubber plenty lighter than the stock tyres you're replacing if you shop around. continental do quite a few in 24mm too.

I run 23mm on my nice weather bike and 25mm on my winter trainer.

If you know the routes and know of very rough roads then go 25mm, otherwise 23mm and keep a lookout!

There are some who won't notice the difference between 25/23 mm.

I find cornering and wet weather riding can be fine on 23mm but use a good quality tread.

I'm trained with 25mm tyres with riders on 23mm no probs.