When is tire rub on carbon a concern?
 

I have a 2011 Ridley Noah with very tight clearances in the seat stays and elsewhere. I run 23mm Continental tires, which actually measure out to around 25mm. I have a significant rub spot on the upper seat stay that has gone all the way through the paint to the carbon, but seems to have stopped at that point. I'd estimate it to be about .5mm deep.

When does tire rub on carbon become a concern?

https://cimg1.ibsrv.net/gimg/bikefor...1211f2e3b6.jpg

It may be alright for now but I would definitely be keeping an eye on that. Put a straight edge to it to gauge the depth.
Why is it only rubbing on one side?
Is the wheel properly centered?

Agree. No rubbing should happen. Do not continue to ride until fixed. Have someone knowledgeable at a bike shop you trust trouble shoot the issue. Good luck.

So what happens when tire ages and stretches 0.5mm? What happens when wheel loses perfect true? What happens when you hit a pothole? What happens when you get in shape and find a bigger kick and the frame flexes more than usual? What happens when tire picks up a piece of sand? A tiny pebble stuck in tread? Why are you living all the way on the edge? Is this how you want to go?

If someone knowledgable in carbon layup tells you there is still a frame there the only recourse is to go find some undersize tires. You're already on 23s. 700x18 is mostly dead stock antiques.

I second every post saying this shouldn't be happening at all. I'd first check for any alignment issues; second I'd get a different tyre. I thought Contis are rumored to run a bit fatter than their stated width - so I'd try Vittorias or Michelins.

Tires should never rub on any frame, but rubbing on carbon is always dangerous.

Wheel is dead-center. There's a tiny bit of rub on the other side, but not through the paint. I guess I just torque the cranks a certain way when climbing that makes it worse on the left.

The millisecond as it occurs is when it is a concern. rubbing is not a good thing under any circumstances. you might need to find skinnier tires or rims or a frame that can support real tires. 2011 and it can only handle skinnier 23s is no bueno in my book. Heck my 1994 Phil Wood race frame can handle 28s and my old 80s Cilo could handle 25s (conti GP classics) Though the Noah might be a bit more aero-dynamic then my old steel frames.

What happens is that you might learn the unspoken (by any sales person at least) cost of a carbon frame. That it's less rugged is some aspects then old fashioned steel is. One benefit of the "claimingly new" trend to gravel bikes is that they tend to have the clearances that out club touring bikes had 40 years ago. Sad how cyclic this activity is. Or should I better say sad that the rehashing of old stuff needs new names to be accepted. Andy

Why??
 

Too ambitious fitting bigger tires than you should?

When judging cyclic activity starting points matter. 40 years ago a great deal of clearance had already been lost. Just took some quick measures from the wife's '73 Colnago Super. Which is a racing frame, not a club touring frame. She has measured 27mm tires mounted. At the rear the tight spot is the chainstays, 6 plus mm of clearance on either side. At the front there is only 7-8mm clearance above tire and below the brake. This is on a 51cm frame, larger sizes would have more front clearance. My bikes are all racing bikes too, but older, they have more clearance.

Spokes don't break with the frequency they once did. Team support is more often on the spot immediately. Or in races with support it is. It is more possible to get away with line-to-line clearances than in past. And it is still a bad idea. Greg Lemond won World Championships with two broken spokes in his front wheel. Outsprinted Kelly and Konyshev with two broken spokes. A modern bike would have a locked wheel.

Gauging where we are are in the cycle usually begins with what you know from where you began in the sport. I began sporting rides over 50 years ago. Privileged to have mentors who were racing 100 years ago. In one case my mentor was second generation of pro in his family. His family was racing bike as soon as there were bikes. I look at 1979 touring bikes shod with 18mm tires and what I think is in 70s and 80s the bike business lost its mind. Others see 70s and 80s as good old days. Perspective matters.

My Peter Mooney. It's first summer. Town line sprint. We're going 30+/ A strong novice puts his QR into my front wheel. Actually, he parked his wheel where mine belonged. I steered away, but that isn't a long term solution, Eventually I had to bring the wheel back under my weight so I leaned my bike into his. Lost 8 consecutive spokes. Tire rubbed hard against my left fork blade but I rode teh bike to a standstill. (Thank you, Weinmann Concave rim for being the stiffest side-to side ever made!) I had a big bare patch of steel on the blade. Had that been carbon fiber, the outcome might have been different.

Oh, that fork had a country mile of clearance.

Ben

This is a great post. :thumb: