ImThatMickey

Question for the group: I have a second hand Kestrel Talon TSR 1.0 that is currently running 700x23 tires. I would like to put larger tires if possible. Does anyone know if this frame / fork can run 700x25 or 700x28? Thanks in advance.

rm -rf

I had an older Orbea bike that barely fit 25mm tires. The space under the front fork was minimal. This was fine on dry, clean roads. But I rode on a newly chipsealed road, with damp stone dust that stuck to the tire, and that thin layer was enough to scratch the paint in the inside curve at the top of the fork, and the noise of this scratching was distressing to me. Yikes! Sand or similar debris can stick onto the tire tread.

I like to use hex wrenches to estimate the space around tires, on the tread side and the tire sidewalls. A 4mm gap is really the minimum I'd want to use. And, especially at the rear tire at the chainstays, if the sidewall gaps are just 4mm or smaller, then the wheel needs to be centered when it sits in the dropouts. Any mis-alignment at the dropouts will have it rubbing on one side.

The 4mm hex wrench is 4mm across the flats. Will this slide in without binding at the fork crown, at both front and rear brake arms, and at the chainstays near the cranks? To go to a 25mm from 23, which is quite helpful for rough road comfort, I'd like to see at least 5mm spacing for the 23mm tire.

I think lots of 9 and 10 speed road bikes were designed before the trend of larger tires. Back then, it seemed that only casual cyclists used 25mm or larger. "Serious" road bikes expected 23mm, and the frames were designed for this.

WhyFi

Check. Usually, you want 4mm clearance at any and all tight spots, between the frame/fork and tire, for debris clearance, wheel flex, etc. You can use a 6mm allen wrench as a feeler gauge - if it clears all of the tight spots, you should have room for a 25mm *of the same tire.* Tire sizing can differ, even within a given manufacturer and likely from one generation to the next (tires have gotten smaller, as of late, to compensate for modern rims which are trending wider).

SoSmellyAir

In addition to the nominal width of the tire, the actual size of the tire also depends on the internal width of the rim, and whether the nominal width was achieved on a narrower or wider rim.

I recently bought a 2000 Cannondale CAAD4 frame and the clearance between the rear brake bridge and the rear tire (nominal width 25 mm, actual width 25 mm mounted on a 622 x 17C wheel) was just over 3 mm.

texbazII

And if your tire does look like it has clearance, make sure your OK with how it removes or installs. I have a 2020-21 lynskey R300 with Di2 11 but I can not remove or install the rear wheel with the tire aired up. Which means when out on the road, get a flat, don't air up till its back on the bike.
And yeah Ive tried all kinds of combinations and moving the rear derailleur.