Drilling holes for internal brake cable mod
 

I bought an used 2014 Ridley aluminum frame road bike to use as my indoor trainer bike, it has external rear brake cable and internal shift cables, none of these mean much to me until I have to mount the bike at the repair stand, since the bike frame is a bit bigger than I normally ride, I end up having to clamp the bike at the top tube because there is not enough seat post left.

The rear brake cable keeps getting pulled enough that it will cause the brake to drag or even lock up, I want to drill 2 holes in the top tube so I can run a new cable housing from brake lever to brake caliper, can't find much info online so I thought this may be a good source

I already contact Ridley bikes twice and my first respond was " we don't recommend drilling into carbon fiber frame " I submitted the same question again and this time I didn't get any reply

Any input will be greatly appreciated, it looks like a simply job but I worry it may compromise the structure integrity of the frame by drilling holes into the top tube

Well, yeah. There's your answer, isn't it.

If the cabling is only a problem when you put the bike up on the work stand, either a) adjust your seat height when using the work stand or b) get a different work stand, which will be a lot cheaper than a new frame.

Indoor trainer bike?
Brakes?
Work stand?

I think a trip to the LBS is in order before installing drillium.

To things
 

Firstly, you can't ride the bike off the trainer if you do this. Your comprising the structural integrity of the frame. Secondly, you kill the resale value (Customer: 'What's that dot I see there' ... Reminds me of that famous Seinfeld episode about the sweater and the red dot).

Scorpiox, there was a recent thread about Miyatas that had internal cabling, and cracked at the holes because the holes had no reinforcements.

The simplest answer IMO would be to get a quick-release seatpost clamp so you can extend the seatpost when you put it in the workstand. You can also get a small band to clamp around the seatpost at the edge of the seat tube, so you can re-insert the seat post at the same depth.

^^^^^^^^^
This

You don't need a rear brake on a trainer.

Either

• Adjust the seat post height when you (rarely if ever) need to put the bike in the work stand; or
• Remove the (never-needed) rear brake cable.

Thank you for the input, resale is not my concern here, I have 6 bikes and this was to be a trainer with possible some road trips.

My first post and didn't take long for the hater to charm in :lol:
Great way to welcome forum newbie mate

This

Clamp the seat tube in the stand.

Better than clamping the top tube anyway.

I didn't take his post as particularly mean-spirited.

My vote is for marking the seat post, then moving it up as req'd in the workstand. How often do you intend to put your trainer bike in the workstand anyway?

I would recommend AGAINST drilling an Aluminum frame even more than I would against drilling into carbon. Any hole in the wall of AL tubing is just asking to develop cracks and structural failure if not done properly. That's why you don't see many AL frames with internal cable routing, and when you do, it's on higher end frames and often with additional support welded/bonded in place.

If that frame will only ever see life on the trainer and will NEVER see road use again... fine, do it at your own risk and it probably will survive, but I would do it under the assumption that if you drill it the way that I think you're wanting to, it's a dead frame and should never be ridden on the road again.

You know the disclaimers.

I prefer to drill carbon fibre way more than anything else.
Reason is many/most times it is made with some bladder and the wall thickness varies anyway and it there is lots of extra material built into it. Then, even broken the stuff is tough. An alloy post/part will snap. Steel with bend and CF will crack. Of course enough force and it will snap too, but materials are different and the tolerances are different.
An Extralite (brand) part will hardly ever be modified. It is already perfect. A CF bar I have no issues drilling, but I understand where the stress points are.

Anyway - your bike is on a trainer. Drill. If you do not know where it is safe to drill, don't. But I think you are fine. Alloy will have tighter tolerances and you do want to be careful.

For example - for a cable - I'd drill in the side toward the middle of the head tube. Not a lot is going on there. If the welds are huge, maybe a weld. If they are finely filed -not a weld. If in the TT...careful. A butted tube in the butt/thicker section farther from the weld would be preferred over the thin area. Since alloy is typically not butted, an inc from the weld is good.
You might feel this with the fork / seat post out.

Take the brakes off. You'll be faster after the weight reduction. ;)

You know, I never put trainer and the need for brakes together.

You'll be faster because you can't slow down.

I don't know what work you'd need to do on a trainer bike that can't be done while it is clamped in the trainer.

Sight unseen - I may be off. But drill through the head tube (as per last post). Go around the steer tube, and take it out right before the seat joint.

I assume you can't take it down the down tube under the BB and to the chain stays. Thought I'd mention.

Do you plan on the housing going in side the frame? Think about smaller holes and stops. There are also stops used for this (for bigger holes) so look for them.

Are you recommending wrapping the brake housing around the steerer tube so it drags? That seems like a terrible idea.

You have to route the housing through the frame, otherwise the brake wire would cut the frame or steerer over time.

You beat me to it. I had a c-worker in the '80s who broke a string of those Miyatas at the hole in the back of the top tube. Miyata kept giving him new frames, usually a step up from the last, with the same drillings. A year later he would be waiting for his next one.

Ben

No. No drag. Like I said, sight unseen is an issue.
A small hole and stop for cable only, or sleeve, not housing in the TT is my suggestion. In several of my frames I could do that. I do similar with Di2 cable, but that is not under tension.

Still, if I read correctly this is a stationary indoor training bike.
Why are brakes needed?

How did you do that without having the bare cable touching the inside of the frame in spots? What kind of stop do you use for an angular exit from the side of the TT?

Drill on the side. The steer tube sometimes has 5mm+ clearance. If you keep the cable in the sleeve, it does not matter if it touches a side, or even bends a reasonable amount.
The exit, I explained has after market stops. I think you have seen them. I can look if needed.

I would drill the top tube in a similar place to where they usually are. Probably close to where the existing rear brake cable stops are. Then with a pin punch or even just the parallel shank of the drill lever the holes a bit so the housing can enter at the appropriate angle more easily. Then run a continuous brake housing from lever to frame. An advantage of this is that your sweat won't get into the brake cable and corrode it.
If you were worried about structural integrity you could fix the housing to the outside of the top tube by other means and not drill it.