azza_333

Would it be ok the drill a 5mm hole into my carbon steerer on my forks, and a 2x 5mm holes into my carbon handlebars to route di2 wires through. like in the following photos


Im not very heavy just 70kg, but do do some light touring with about 6-8kg of gear

bikepro

I wouldn't do it. I'm sure it will weaken the part. I'm sure others will elaborate.

azza_333

Im sure it will weaken it but a 5mm hole is very small, so will it break enough fibres to weaken it enough to be an issue.

Blue Belly

Carbon fiber is great to work with. Are you skilled with a drillpress? A nice even cut should go nicely. It will void your warranty, I'm sure. I was pretty leary when I built this guitar. I had to route the pickup sections & drill some holes,cut the binding channels. It was really easy & all the cuts had nice smooth edges.


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rm -rf

Both those steerer and bars are aluminum, not carbon.

You still the the Di2 control box under the stem, with the shifter wires running to the box, out from under the tape. Then one wire heads to the back of the bike. Routing it up and into the bars won't be any better than sending it directly into the hole in the downtube, and a lot more aggravating to install.

The control box is needed for plugging in to recharge, the adjustment button, and the battery charge level light.

azza_333

I havent really used a drillpress that much. I do have a workshop at work with armourers, mechanics, and technicians that I can get todo some work for me, but I highly doubt they have worked with carbon fibre before.

azza_333

I know in the photo they are alloy. And I am weel aware where the junction box is expected to go, but I dont want it there, I want it internal.

I just want to know can I drill into my steerer handlebars with out to much risk.

rm -rf

So you are going to somehow permanently connect a usb cable out the side of the internal box and route it to the outside of the frame? And just guess how often to recharge? (I recently ran down the charge into the red in just 400 miles of all rolling hills.) And give up trim adjusting the rear derailleur?

Cutting carbon:
I have no idea if it's safe to cut the steerer.

I had used a compound miter saw to cut an aluminum seatpost. It made a very clean, straight cut. So I tried the same thing with a carbon steerer. I did a test cut up high on the steerer. Even at a slow feed rate, the high speed blade immediately fractured the carbon, splitting the grain and ripping out small chunks. I quit immediately, then recut farther down with a hacksaw blade, going slowly, light pressure.

If you are drilling, I'd use the very low screwdriving speeds and very low pressure on the drill bit. Take your time.

Andrew R Stewart 

I would suggest that a failure of a guitar has a pretty small after math. Steerer failure can produce a far larger negative result... Why are external wires so wrong?

One aspect that I think of right away is that placing anything inside the frame makes doing service or future changes so much more problematic. Intergration is a cool idea if kept in a vacuum from future designs and shifting preferences. Andy.

FastJake

Drilling into a carbon steerer or handle bar (especially in the middle, where you want to do it) is a really bad idea. rm-rf's experience cutting carbon is the perfect example of this. You won't get a clean hole like you would with metal. Fibers will be torn, there is no way to avoid this, and your holes will be the perfect place for cracks to start. And since they're in places where you can't see them you'll have no idea when you have a problem.

I've owned carbon bikes and am not a paranoid safety freak like some people, but there's no way I'd drill into the middle of a carbon bar or steerer tube.

azza_333

Ok, Its a really dumb idea then. I might just get an alloy them drill a couple of holes in it and hide it in the stem then. Thanks for everyones input.

AnkleWork

The great thing about carbon is that it fails suddenly and catastrophically. Just think of all the trouble free miles* the OP will have before any problem surfaces. I just hope someone posts video.

* assuming the OP actually rides

PS: Drilling an aluminum stem is probably a worse idea, just FYI.

Blue Belly

a handle bar is pretty thin. A steer tube pretty thick. I don't think it would be a big deal. I wouldn't do it on a handlebar. Of course, there's no guarantee. But, carbon frames quite often have routing holes. I agree that if it's hidden, you Won't see potential problems. As stated before, cutting/drilling into carbon yielded really clean results. My carbon fibre guy insured me that the was the norm. It's not like cutting a hole into denim. & part of what makes CF such a great medium is that you have the strength of a weaved fabric bonded to a solid. It's along the same lines as stressed skin construction(airplanes are a good example), where the sum of the parts working together allow for lightweight & superior strength

jfmckenna

Super cool. As a luthier myself I very much appreciate that. Is this a hobby of yours or do you sell guitars?

Blue Belly

. I was building/selling for a while. Not at the moment. Blue Belly Guitars. I'll get back to it eventually. Life has sort of gotten in the way...