Maybe 25, but that’s probably as big as you can go.
How does it fit near the seat post and chain stays?
ChillinDylan901 on
The chain stay is most likely your limiting factor
wrongwayup on
1/4″ is north of 6mm. Bet you could def fit 25mm, maybe more.
Keep in mind the 25mm measurement is a theoretical diameter, and you’re looking at a radial clearance to that brake arm (so, half the diameter).
That said each tire fits different so there’s really only one way of knowing for sure…
greenscoobie86 on
25 or a skinny 28(possibly)
chris_ots on
From my experience with old steel road bikes, almost definitely a 25 will fit. You need to check the chain stay at tightest part next to the BB, as well as the top of the fork though.
If there is lots of space, maybe even 28s!
dyebhai on
If you’re willing to swap the brakes and wheels, you could probably fit a 650b by 40… It’s almost certainly more effort than it’s worth
restart52 on
I squeezed some 700c x 28’s on my road bike. Biggest it would fit
PHILSTORMBORN on
A way to gauge it is to to take a set of allen keys and see which size matches the tightest clearance. For instance if a 3mm allen key wedges somewhere that is very different to comfortably getting a 5mm around everywhere.
Tukkeuma on
It’s just that even if you manage to fit 25, that tyre will collect dirt and rocks and it might cause rubbing noises. It needs to have some clearance even if the tyre itself fits.
CommunicationTop5231 on
Have you measured the actual inflated width? Given that a 25 is only one more mm on either side, I’d be surprised if you couldn’t make it work by just resetting the calipers so that they’re a little wider OR upgrading to newish 105 dual pivots, which would improve the braking performance a lot anyway while clearing wider tires.
Gullible_Raspberry78 on
I think you could put 25 Contis on pretty easily
Plastic-Gift5078 on
I wouldn’t. New 25’s might fit but tires do stretch and you can run the risk of something getting wedged between tire and fork/frame. Not worth the risk.
13 Comments
You might fit 25 depending on manufacturer.
Maybe 25, but that’s probably as big as you can go.
How does it fit near the seat post and chain stays?
The chain stay is most likely your limiting factor
1/4″ is north of 6mm. Bet you could def fit 25mm, maybe more.
Keep in mind the 25mm measurement is a theoretical diameter, and you’re looking at a radial clearance to that brake arm (so, half the diameter).
That said each tire fits different so there’s really only one way of knowing for sure…
25 or a skinny 28(possibly)
From my experience with old steel road bikes, almost definitely a 25 will fit. You need to check the chain stay at tightest part next to the BB, as well as the top of the fork though.
If there is lots of space, maybe even 28s!
If you’re willing to swap the brakes and wheels, you could probably fit a 650b by 40… It’s almost certainly more effort than it’s worth
I squeezed some 700c x 28’s on my road bike. Biggest it would fit
A way to gauge it is to to take a set of allen keys and see which size matches the tightest clearance. For instance if a 3mm allen key wedges somewhere that is very different to comfortably getting a 5mm around everywhere.
It’s just that even if you manage to fit 25, that tyre will collect dirt and rocks and it might cause rubbing noises. It needs to have some clearance even if the tyre itself fits.
Have you measured the actual inflated width? Given that a 25 is only one more mm on either side, I’d be surprised if you couldn’t make it work by just resetting the calipers so that they’re a little wider OR upgrading to newish 105 dual pivots, which would improve the braking performance a lot anyway while clearing wider tires.
I think you could put 25 Contis on pretty easily
I wouldn’t. New 25’s might fit but tires do stretch and you can run the risk of something getting wedged between tire and fork/frame. Not worth the risk.