JohnUSA

I bought a carbon Salsa Cutthroat for bikepacking, and I put a bunch of clear gorilla tape on the frame to protect it from cable and bikepacking bag rub.

Well, my friend and I did 1250 miles of bikepacking in 12 days, and when I got done, I took off all the bags and noticed a big wear mark on the head tube. I guess I missed a spot with my tape. Needless to say I put a bunch of tape on that spot for future trips.

However, do you think I did any real damage to the frame with this wear mark? Is it a cause for long term concern or is it just cosmetic? It’s fairly deep but not crazy, and it’s not really that big. See attached picture.

Thanks,

John

easyupbug 

I would take a couple more photos at angles and post on the Bicycle Mechanics forum where frame damage comes up often. Having a professional look at it in person is always best, if you live near a good size city there will be a carbon repair shop to get an opinion. That said and seeing only one view from a photo which is not good that type of abrasion wear should not create stress risers (cracks) but I can't be sure whether fibers are cut which can be problematic.

PeteHski

I would pay more attention to the rub marks on your forks.

Atlas Shrugged

The carbon fear porn continues. Listening to the paranoid members of this forum there are carbon bikes collapsing under people by the thousands caused by the smallest scratches or rub marks. You just hauled that bike 1250 miles fully loaded and that little bit of rubbing is a concern? It has proven its durability. You have a very robust quality-built bike specifically designed for that use, don't give it a second thought and start planning your next epic adventure.

For reference, I rode this carbon wheel over 1,400 km retracing the Ho Chi Minh trail in Vietnam as no replacement wheel was available, without issue.

Branko D

I'd colour it over with red paint in a couple of layers to protect the carbon and fix it visually, and protect the area with tape better.

It’s not good, but 🤷 ​​​​Bikes acquire scratches and damage over time if used.

Germany_chris

What do you think is harder..your carbon head tube or you cable casing??

"back in the day" there was a YouTube video of the founder of Niner beating on the fork and downtube of a carbon bike with a hammer, if he didn't break the bike with that hammer you're not going to break yours with some rubber

tempocyclist

It looks superficial, just cables rubbing the paint away. It shouldn't cause any harm. *

Clean it up, get some red nail polish and paint it to match. Then pop a frame protection sticker over the top.




* That said, I am not a carbon fibre technician, expert or whatever...

Hiro11

In fairness, improperly routed and improperly maintained cables burn right through carbon all the time. The recent Tarmac SL7 recall is a good example. Talk to any mechanic, it's a common problem. It's not the cable housing, it's grit getting between the cable housing and frame that causes the damage.

Still, to the OP: it looks like nothing to worry about to me. Get it checked out if you're worried. Paint protection tape works really well in preventing this.

mstateglfr 

Based on housing wearing thru carbon, it appears housing is harder.

Bmach

It is paint wear. Get some matching nail polish, paint it, then throw away the gorilla tape. Use something like 3m paint protector that is made for what you want to do. Here is the link https://www.3m.com/3M/en_US/p/d/b40066703/

Branko D

Water wears away rock all the time, and there's no doubt what is harder of the two. Constant rubbing with a softer material will wear the harder one just fine.

vespasianus

The cable housing without question. It will cut into aluminum and steel just as easily. You have no clue what you are talking about.

Atlas Shrugged

Not necessary.

Pratt

Don't have, and have never ridden, a carbon fiber bike, but I've used a lot of epoxy. The strength of composites is in their fibers. Manufacturers go to considerable lengths to minimize the resin:fiber ratio. If, as pointed out, the fibers are not damaged, just fill the defect with resin, ideally to match the strength of the original, epoxy or polyester, sand and paint it. Even if some fibers are abraded, the tube could be reinforced wth a patch. It might not be pretty, but could be stronger than the original tube.
Good luck.

Badger6

We should probably kill this misconception right here. A bare cable dragging over the top of carbon could cut into the fibers, if it doesn't break while cutting through the epoxy. A housing dragging over the carbon will also cause wear. As for implying it both a fast and common occurrence...that's a whole new one to me. Has anyone else ever heard of this?

As for the SL7 recall, it had absolutely NOTHING to do with cable routing. I know because I own one that has already been corrected.

Hiro11

https://www.google.com/search?q=cabl...hrome&ie=UTF-8
Alternatively, here's an entire recent podcast episode on the topic: https://cyclingtips.com/2021/10/nerd...cable-routing/

The problem only exists with Tarmacs that route the cables right next to the steerer. First Specialized introduced a steel shim between the cable/bearing assembly and the steerer, finally the introduced a huge expander plug to reinforce the entire steerer internally. These problems were clearly caused by the design of the headset that routed the cables alongside the steerer. As the podcast above notes, similar problems have been found in many brands.

vespasianus

In the MTB word, people have had there cables cut into their fork crowns - enough to make the crowns unsafe. The sawing motion is what it is all about. Yes, improperly routed cable that rub up against a head tube every time you turn can cause big problems.

But in the OPs cause, that does not look that bad. A coin test will tell you if that is just paint or something more.

Badger6

Okay, I'm just gonna say it, because apparently what should be obvious isn't. If you are riding a bike where your cables (bare or the housing) are dragging on the frame, isn't it obvious that you should reroute/rerun the cabling? I, mean, it's crazy, I know, but if I re-cable a bike and the cabling is dragging on the headset when I turn the bars full left and right, I redo it, or put little rubber pieces on the cables to protect the paint. Maybe that's why I've never sawed off a headset.

Also, the problem with the steering tubes on the SL7 is only due to "improper" routing if you make an illogical leap to the routing of the cables inside the head tune is what causes the design of the headset to potentially cause damage to the steering tube. It's absurd. Yes, the headset was designed to pass the cabling through it, to decreed the cD of the headset...the problem arose from improperly supporting the structure. That isn't the fault of the cables, it is the fault of engineering the design. Hence why they introduced an expander plug that is about 1cm longer than the original spec'd one and redesigned the collar that holds the cabling in place so the collar wouldn't damage the steerer in a scenario of hard impact to the front (like a pothole). There was no issue of cables cutting the steerer.

mstateglfr 

Internet pictures of steerer wear due to internal cable rubbing means this isnt as simple as just rerouting the cables. James Huang at CT actually helped a company avoid an issue a handful of years ago when he pointed out that the bike he was testing had some structural wear from housing. Routing housing thru the stem/headset is a slick look, but it doesnt appear to be fully baked, as the c-suite folk like to say.

Badger6

That may be. To the specific case of cable/hose routing through the headset of 2021 Specialized Tarmac SL7, the recall was not due to cables or their housings causing wear on the carbon bits. Not even remotely. Search for and look at the pictures of the 2 damaged steerer tubes that led Specialized to issue a voluntary recall. The damage was clearly not from cabling. Maybe it's caused issues in other bikes from other manufacturers. I don't know, I don't ride them, so I'm not really concerned.

As far as damage to the paint of a frame around the headset, the solution is pretty simple, redo the cabling.

mstateglfr 

I havent referenced the SL7 issue in my comments here, and have both read and listened to what the issue was for that issue.

Wattsup

Replace it with a metal head tube.

danimal92sport

I’ve had a cable wear several mm in to a cast MTB head tube over a 3 year period. The cable was essentially undamaged, but the head tube nearly wore through. This is common - I’ve seen deep wear from cables on MTBs many times over the years - I’m surprised at some of the folks being surprised. Tells me they haven’t been biking or wrenching for very long or only ride road on clean streets when it’s dry out. How much fun is that???

If that were my Cutthroat, I’d fix my terribly ugly tape job first. Then I’d put either some super glue or, better yet, red paint over the worn spot. I’d then check my bike over for other cable rub spots and I’d tape em.

First thing I did when I got my steel Salsa El Mariachi was to tape under the cables - I didn’t want to wear thru the paint and get rusty spots but I also feared the cables rubbing in to the steel. That bike sees trails but also adventure races, bike packing, etc. Lots of dirty, gritty miles.

Dan