snowranger

Hi just joined this forum. I bought a road bike the other day with carbon stays and no eyelets for a rack. I ordered a Sherpa rack that will use the quick release levers and clamp to the stays. OMM indicated that the carbon stays would be fine with the rubber-coated clamps. Anyone have experience with this set-up, any issues? TIA.

vik 

I don't have a carbon bike, but I do use that rack. The P-clips that go on the stays only stop the rack from rotating forward or backward. They need to be tight, but you don't have to go crazy when you attach them. OMM guys are pretty switched on and all the advice/support I have rec'd from them has been great.

snowranger

Thanks, all the LBSs were telling me no way on the carbon stays. Looking forward to a dry back on the commute.

balsingh

Well I also use that rack, but my bike has an aluminum/composite frame with carbon fork, so it's not quite the same as your set-up. However, I would think that carbon would not be the ideal material as it would stress under the pressure and weight of the load because it's concentrated in those two small areas along the seat-stays. Furthermore, the direct pressure from your rack's load would most likely weaken the carbon in a critical part of your frame, creating a potential nightmare. However, I'm not OMM and don't have that much expertise regarding racks and bike materials, but that's my two cents. If I were you, I would steer away from it as I know that carbon and racks don't mix as I don't have a front rack because of my carbon fork. Also, how much are you expecting to carry and for how long?

Bal

PS. I just looked at my Ortlieb Handlebar Bag instructions and it specifically states to not mount to a carbon handlebar. So I would most likely try to avoid adding anything to your carbon frame if you can.

snowranger

Probably a grocery-bag full for commuting. This is what OMM wrote: "a Sherpa rear rack with a set of 3/4 clamps for the upper attachments will work great, no worries about the carbon stays, the clamps are rubber reinforced."

Thinking about it, since the upper clamps would only stop back and forth movement and the rails that extend to the stays are made of thin metal, I am thinking that the forces are not that great. A lot of the shock would be absorbed by bending of the rails and the rubber materials.

balsingh

Well I'm sure it'll turn out ok. But I wouldn't do it because I think that the carbon stay would weaken over time, even if it's mainly due to lateral movement. But once again, I would trust OMM. Either way, I hope it all works with no big problems.

Bal

BigBlueToe

I saw this on another post:


If this is the rack you're considering here's what I think I'd do. I like to be on the safe side and I like to monkey with things. If I had carbon seatstays I think I'd be worried about the narrowness of the P-clamps on the stays. I'd try to rig up some way to distribute the load over more surface. Maybe use two P-clamps attached to a metal piece that attaches to the rack. That would double the surface. Of course, I'm no engineer.

snowranger

Thanks for the suggestion BBT. The geometry of my bike is different from the one on the OMM site as seen below. I might try attaching the rails to the monostay above the brakes which is aluminum. The rails look like they can slide further out.

flipped4bikes

If the carbon stays can't hold up to groceries, they aren't going to hold up to just riding...

vik 

Those upper clamps only stop the load from rotating forwards and back - they don't support any of the weight of the load. Just don't tighten the P-clips too much [they don't need to be uber tight] and you'll be fine.

BTW - OMM can set you up with extra long "rails" if you want to attach to the monostay.

snowranger

Thanks Vik. OMM did say they have extra long rails, but I'll try the carbon stays first.

nickbb

Hi All,

I thought this might be helpful if I posted my solution to the OMM rack and carbon rear stays concern. So that others might come across this in their searches.

I have an avanti road bike with carbon seat post and rear stays - no eyelets/braze-ons.

I mailed OMM and they said there were no problems with the p-clamp / d-clamp on the carbon stays. However I wanted something which was easier to remove and didn't mount onto the stays - just in case.

The solution i used was described in another forum using the seat post clamp with rack mount. See here the link to the product on wiggle.
https://www.wiggle.co.uk/au/mpart-sin...th-rack-mount/

I ordered some 13" extenders and bent them into open Z shapes to bridge from the seat post clamp bolts to the rack width. Then mounted the rack to the axel as per OMM instructions.

Here's a picture.


I am quite happy with the result, and it allows me to remove the rack very quickly for weekend training rides.

Hope this helps some others out there.

Cheers
Nick