Carbon frame woes

aidso

https://imgur.com/a/zEdH58L
My friend is in a bit of a pickle. He has damage to his carbon bike (pictured) and the manufacturer has said it was caused by the bike carrier (pictured). While I concede that is possible, in my opinion the damage is too high to be caused by the clamping arm and must be something else; or something else initially created the damage and the clamp finished it off.
At that height, I would argue that the clamp would have to have been closed OVER the cabling and thus wouldn't lock. I'd also suggest that at that height, even under the cabling, the clamp wouldn't lock because of the angle and the bike would fall out, or rock massively. The damage is too high...

I don't have a picture of it in the rack, but here is another link with a different bike mounted - same rack, side, angle etc. You can see how low the arm mounts around the bottom/bracket nearer the chain rings.
https://imgur.com/a/3dHDSCj

Is there any way to prove or disprove the carrier did the damage?

wilberforce

What does your friend say?. When did he notice the damage?

Either he noticed it when he removed the bike from the carrier, or there may have been some other impact to the frame

aidso

Noticed approx 5 days after a ride, while washing

robertpb

That looks like the clamp damaged the frame, it's a strange place to get damage whilst riding.

Did he clip a low branch when the bike was on the rack.

cougie

He could have hit it on a rock that flicked up or something too.
Even if you rule out the bike carrier it doesn't mean that the manufacturer is responsible.

Easy enough to get it fixed though.

JBA

I'd say that damage could well be from the carrier clamp. I have the same carrier and the clamps can move if you set them too high up the down tube. He could have done that and the clamp has moved during transit allowing the bike to rock in the clamp.
Alternatively he has accidentally tightened the clamp when the down tube wasn't central in it. Put the bike in the rack and see how well the damage lines up with the clamp.

steve_sordy

I have never liked that position for a clamp, it allows a lot of leverage. As the car corners, the weight of the bike goes sideways and levers onto the clamp.

Was he using any sort of foam padding in the clamp to spread the load and avoid concentrating the stress? I can see that the jaws of the clamp have some sort of rubber in them, but it will be hard rubber for longevity. Unless the curve of the jaws fits the shape of the downtube at the point of clamping then the jaws will be concentrating the clamping force onto corners or points. Add the bike rocking from side to side........

The damage may have happened over time. First a crack, then the crack spreads as further clamping and riding spreads it.
It may have been a normal ride that caused the final damage that made him notice it!

Message to all carbon fibre framed bike owners out there; use foam in the jaws and do not overtighten!

larkim

Once a manufacturer has concluded where they think the damage has come from, unless you get some sort of expert forensic report you'll not get them to change their minds. It's certainly possible that that sort of damage is clamping related, and more likely that not whatever the cause is it doesn't look like a manufacturing defect either.

So I'd be asking them what preferential repair options they can price for and just suck it up.

aidso

Yeah, im in the "suck it up" process now. It's a hard pill to swallow given how many bikes i've transported over the years and this the first one to go - an expensive mistake. It could encourage me to purchase one of the newer Thule or Yakima carriers to avoid problems in the future as I dont think padding/foam would fit between the frame and the jaws and be able to close.

moonshine

get it to fybrelite https://www.fibre-lyte.co.uk/fl/fl_frame_repairs.html for inspection, ultrasound? and repair. you might need a paint job but should be repairable

steve_sordy

moonshine wrote:

get it to fybrelite https://www.fibre-lyte.co.uk/fl/fl_frame_repairs.html for inspection, ultrasound? and repair. you might need a paint job but should be repairable

Very helpful post moonshine!

I have entered that company into my biking file. (Just in case). :shock:

larkim

Ah, so it’s not your friend who’s after the advice; it’s you aidso?

The Rookie

steve_sordy wrote:

I have entered that company into my biking file. (Just in case). :shock:

Bad idea, you're old enough to know what effect that will have I think....... you may as well have them on speed dial now!

steve_sordy

larkim wrote:

Ah, so it’s not your friend who’s after the advice; it’s you aidso?

Yes, I spotted that too, but I thought it would be more diplomatic to keep quiet. :roll:

Dan_xz

I used to have the sameThule rack. It uses pretty hard material on the clamp which has a pretty small surface area.

They made a special add-on for use with carbon frames for this exact reason

https://www.thule.com/en-gb/gb/bike-rack/roof-bike-rack-accessories/thule-carbon-frame-protector-_-984000