Chainstay rub

mrb123

I seem to be getting a bit of light chainstay rub all of a sudden on the non-drive side chainstay of my carbon summer bike.

I've had the same bike and wheels for several years but this seems to be a recent occurrence.

The wheels themselves appear to be true and have no obvious loose spokes. They're a handbuilt set with Archetype rims.

I also get a bit of rub on the rear brake pads if I have them set too close, but only when I'm on the bike - they don't rub when the bike is on the workstand and the wheels appear true as I've said.

Is this likely to be an issue with my spoke tensions on the rear wheel or could there be another cause? It's hard to think it's frame or hub flex when it has only recently started becoming noticeable.

Thanks in advance.

i.bhamra

Same tyres? Slightly different width could lead to noticeable rub, maybe even the difference in tolerance between 2 tyres from same batch??

fenix

I think your wheel has shifted slightly in the drop outs.
Loosen it off and move it back and re tighten.

Fits with it being the non drive side. The wheel can shift that way if not 100% secure.

mrb123

Thanks for the comments above.

The tyres are 25mm Conti 4000s, same as I've always used on that bike. When the bike is in the workstand the wheel and tyre spin straight and true with a few mm of clearance either side so there must be some movement or flex happening when I'm actually on the bike.

I'm not sure if it's the position of the wheel in the drop outs either. I've had the rear wheel off and on a couple of times but it's still happening. When I do up the QR I always do so with the bike on the ground and using a bit of downward pressure to make sure the wheel is properly seated.

step83

On the floor take the skewer out the wheel will sit as the hub ends hold it in place. Check the skewer is not bent, both springs are present. also check the drive side drop out. some frames you have the sacrificial hanger being part of the drop out, if its bent or damaged, or even the bolts loose/missing it can through it out.
I actually had this on a frame, my brake bridge cracked bike "felt" a little odd under braking but the visible sign bar a crack was the wheel riding at an angle when I was on it, unweighted it was fine and actually hid the crack. Sitting on the bike caused the bridge cray to splay apart allowing movement and the back wheel to basically crab off slightly. On a disc you dont have said bridge usually but the crabbing would bind the disc up in the pads. on a rim brake you would expect excessive brake rubbing and possibly even feel the wheel try an straighten as you brake.

Worth checking the condition of the non drive side drop out, thats rarely an issue but check it off.

Next up, the wheel, check the spokes see if any feel loose, if not onto the hub, could be a failed/failing bearing I've seen it sometimes where the end cap is loose so the bearing can wander casing the hub to drop slightly at an angle on the spindle, you'll see where mark on it.


Of all the above I would likely go with a hub bearing issue. But not knowing the frame or wheel plus not seeing it its hard to say for sure.

mrb123

Cheers Step. I'm going to have a proper look at the hub (Bitex) this weekend to see if there's any play anywhere.

step83

Bitex should be a pair of 5mm allen key fittings to dismantle the hub from memory

mrb123

Seems to have been an issue at the hub. Everything has been tightened up and no longer rubbing the chainstay as far as I can tell. I suppose it doesn't take much play at the hub to cause an issue when clearances are fairly tight.