25c vs 23c - clearance for cruds

chrisaonabike

How much higher do 25c tyres sit above the rim than 23c ones? That is, how much do they increase the total diameter of the wheel + tyre?

There don't seem to be any disadvantages in terms of speed or comfort, but I'm wondering about clearance between the tyre and the brake arch - with 23c at the moment, I want my Crud mudguards to still fit with the 25c.

turnerjohn

depends loads on the tyre maker....I went from 23mm Mich to 24mm Cont and ran out of room :evil:

dee4life2005

I went from 23mm GP4000s to 25mm, and the 25mm left about 1mm clearance between the tyre and the forks - no chance of mudguards fitting.

If it's the crudracer mk2 mudguards you're talking about then I think you'll struggle with 25mm tyres, especially the GP4000s.

MrSweary

Depends entirely on the bike. I have Crud mkIIs on my Felt in winter and run Conti 4Season 25s with no issue. Clearance without the guards is a tight 5mm.

chrisaonabike

oxoman wrote:

If you mention what bike / brake you have hopefully you might find somebody has already done the hard work for you.

It's a Giant Defy 3 Composite 2012, Tiagra, unmodified.

Looking at the back wheel, the fork clearance is much tighter than the brake arch. There's about 1.5 mm above the crud and below the fork, and if I push the crud down on to the tyre it moves down another 1-1.5mm - hard to tell without taking the crud off and measuring it all exactly.

So it's going to be touch and go with 25c.

Be good to know if anyone with the same bike has tried it though, as you say.