25mm tyre rubbing on front derailleur clamp

[dev null]

Help dear tech savvy roadies.

 

My son has a Cannondale Supersix frame and I today replaced the 23mm Gatorskin with 25mm GP4000 tyres. Now we have a situation where the rear tyre is rubbing against the front derailleur clamp.

 

What are my options? Is it safe the file the clamp to get clearance? The clamp is quite thick. The FD is a 2011 model SRAM Rival FD.

[Kalahari Vegmot]

Heck, I would definitely try that.

 

How's the rest of the clearance if the fd's is so tight?

 

Pitchas

[Schnavel]

My mate had the exact same problem.

 

Try the following:

 

1. Not all tyres are the same, so either try a different tyre or put the front wheel at the rear to see if this makes any difference at the rear - I have had a 25mm conti that caused frame issues, but when replaced with another tyre of the same, it was perfect.

 

2. You can purchase an aftermarket derailleur clamp. Carbon ones normally do the trick as they are thin (think seat post clamp)

 

3. Contis are also known for being large tyres. 25mm tyres are similar to 27mm fyres for other brands. Changing the tyre brand could also solve the problem

[dev null]

Here is a mug shot of the offending party...

 

 

[Meezo]

The way that pic shows, i reckon 25mm ain't gonna work.

 

It will solve you from doing anything if you remove the clamp completely and check

[dev null]

The way that pic shows, i reckon 25mm ain't gonna work.

 

It will solve you from doing anything if you remove the clamp completely and check

 

That photo is a bit misleading. At the closest point there is about a 3mm gap between the tyre and the frame. 

 

I hate it when the frame designers make the tolerances so tight. My BMC SLX01 frame (also a circa 2009 - 2010) has a much better design to cater for tyre clearances.

[Vetplant]

The way that pic shows, i reckon 25mm ain't gonna work.

 

It will solve you from doing anything if you remove the clamp completely and check

Have to agree here. Remove the clamp and measure the clearance to the frame, then we will know what we are working with. If it is around 2 to 3mm clearance I would advocate for dropping the FD and going 1x,

 

If clearance is closer to 5 to 6mm we might be able to trim the clamp down. However everything in me screams at me to not file away at any bracket on a bicycle.

[ichnusa]

go 1x!!!

[Rocket-Boy]

diy it with a file, worst that happens is the clamp gets ruined and needs to be replaced. Is it a clamp with a braze on or a clamp on fd?

[Vetplant]

That photo is a bit misleading. At the closest point there is about a 3mm gap between the tyre and the frame.

Have you tried moving the offending bracket a little bit up or down the seat tube so that it doesn't coincide with the point where the tyre is closest to the frame? Usually the actual shifting mechanism has some play to work with.

[BaGearA]

File it and see what happens

[dev null]

go 1x!!!

 

On a roadie? Really? For a 17 year old? UCI and CSA will have a fit. They are already anal with their rear cassette ranges for Juniors.

[dev null]

diy it with a file, worst that happens is the clamp gets ruined and needs to be replaced. Is it a clamp with a braze on or a clamp on fd?

 

Clamp on FD.

[dev null]

Have you tried moving the offending bracket a little bit up or down the seat tube so that it doesn't coincide with the point where the tyre is closest to the frame? Usually the actual shifting mechanism has some play to work with.

 

I moved it down as far as I can without the FD touching the front chainring.

[King_Crispy]

It's like trying to fit a 650b tyre onto a non-compatible frame.

Or in simple analogy: trying to shove a marshmallow into a keyhole.

Ain't gonna fit....

[Meezo]

So a quick scan on the interwebs say it's dependant on rim tyre combo, in 25mm of course. Most of them say it's close about 1-2mm. There a few reports of rub, which they then swopped back to 23mm, some have said changing skewers has worked, but I can't believe that without actually trying it