On a clean of my bike ive discovered once again that i have tyre rub marks(through to the carbon) on both sides of the chain stays.
This is the 3rd bike in the last yr and half that its happen on.
Just wondering if anyone else gets this issue on there bikes,and if theres a solution other than getting something like a gravel bike that just has more space in the rear.
I weigh 89kg and have a 365 ftp,and i get issues basically anytime im out the saddle the frames ive had issues with have been felt AR,Cervelo S3(disc) and enigma evoke.
Ive tried maxxis refuse ,schwalbe pro ones,conti 4000 and hutchinson fusions. all in 25mm.
the wheels where easton ec90 50mm,dt swiss dicuts and light bicycles 60mm carbon clincher on dt 350,all have been either 24 or 28 hole wheels
3mm is very tight but 5-6mm should have been fine. Have you checked spoke tension? Maybe that could have been low if the wheels were new and worn in a bit. Riding in dirt or sandy conditions can also be the cause especially with the felt.
I’m a similar weight and power as you and have exactly the same issue on my S3 Disc with 25 mm Conti GP4000s, wasn’t really an issue until I took it out on country roads in the rain and there was a good deal more wear, I assume from the grit in the water. I found mine was just on the non drive side though given the asymmetry of the rear chain stays. Its a real shame as the bike is rides beautifully on 25 mm GP4000s!
In the end I resorted to dropping the rear tyre size down but plan to try run 23 mm on wide internals to give a c26-27 mm rear tyre.
Then how freaking aggressive when you ride out of the saddle
I never had this kind of problem and I have no clue what it can be after my other suggestions.
Aha ive been a cat 1/2 racer so i can ride pretty aggressively ! .Yeh i was out of ideas hence coming here,maybe i just have to face that it going to be an issue.
Sorry I’m not familiar with the bike models but this is where I’d start:
Do you experience brake rub (if the calipers are on the seat-stay). If yes, then I’d start with upping the rear wheel spoke count (There’s an article on slowtwitch somewhere that explains this idea. Maybe 2014). If you didn’t know, there’s no aero penalty for added spokes just a 4-6g weight penalty per spoke. If you don’t have SS caliper brakes then maybe you could fab something with zip ties (and a paint marker?) to see if you’re getting wheel flex there.
If you don’t have brake rub then check the spacing in the CS with your wheel and tire set-up. As others suggest you might not have enough room. When I’m designing a bike I spec at least 5mm space for the client’s specified tire width. So if a client says they use x-rim and y-tire @ 80PSI I take calipers and measure the tire width (as you know tire mfgs aren’t the most honest with their labeling and internal rim width has an impact). Then I’ll adjust the spacing, bend, dent, whatever to make sure there’s enough space (hard to do that with stock CF bikes)
Out of saddle technique: At your weight and power if you’re really plowing out of the saddle (especially if you’re tired) you might be pushing the pedals (and bb) left and right instead of up and down. I only mention this because I’ve ridden with some beastly guys on whippet-like bikes (e.g. Vitus 979 bonded aluminum) that never experienced rubbing issues. Necessarily, they were some of the smoothest riders I’ve ever seen. I don’t want to bag on you or your riding skills, it’s just something to think about. And, yes, there’s always going to be some lateral movement when you’re “jammin”
It’s highly unlikely that excessive wheel flex is the problem here since the bottom bracket and chain stays are very close to the axis that the wheels flex around.
Here’s a link to the article on slowtwitch:
Of particular not is the fact that stiff rims actually increase the likelihood of brake rub rather than decrease it. From memory, the nice wheel deflection diagram was from a study that Mavic did.
It’s totally possible that wheel flex is the problem. I didn’t read that whole article but I know I had a Zipp wheel that rubbed my frame constantly while every other wheel on that bike didn’t. Why or how… I don’t know. Could have been the spokes. Could have been the rim. Could have been the Willie Nelson. Could have been the wine. I just know it did and others didn’t.
Edit: I read a bit more of that article. It doesnt say wheel rub is unlikely… It explains that we may not properly diagnose the issue and that the “stiffness” is not the only cause.
I have a 2018 S3, i have just upgraded to 50mm Carbons (25mm external) with GP5k’s i have got a huge amount of rub on the inside of my chain stays, its gone through into the carbon. i tried running 23mm tyres and still the same, i think it is down to the width of the wheel and not enough clearance. i say that, but i am a big guy. im at a loss as to what to do as 90% of wheels now are atleast 25mm wide.
Hi there TaffNind did you ever get to solve this problem? What was the internal width of your wheelset? I’m also building up a 2018 s3 disc frameset and I’m a bit wary on the rubbing issues.
I had a similar problem with my caliper brake 2014 Cervelo S2. Had it on the trainer all winter (tacx wheel on trainer) and one day noticed major rub through on the inside of the left chainstay and then notices the wheel did not seem to sit perfectly level/straight. Took it to the LBS and they measured the frame and found the rear triangle was out of alignment. No idea how it happened, LBS sent pics to Cervelo hoping for potential warranty but they said no.
.Yeh i was out of ideas hence coming here,maybe i just have to face that it going to be an issue.