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Stiction in internal cable routing(3 posts)

Stiction in internal cable routingAsh
Apr 8, 2003 9:47 AM
I have a custom steel frame with internal cable routing in the top tube for the rear brake.
There is a brass tube placed inside the top tube.

I just can't get the thing set up right without a lot of stiction. I tried spraying WD40 through it and blowing it out with a compressor to make sure ther wasn't anything inside of it. The stiction seems to be at the entrance/exit of the internal tube. Like the cable is scraping on the tube as it enters and leaves it.

I've tried new housings/cables, dry, lubed... When I compare it to my wife's bike with external cable stops hers feels like butter.

I'm using Campy Chorus 9sp levers and calipers.

next step is to try GORE Ride on housings/liners

any tips would be appreciated

Thanks
anything inside the brass tube?jw25
Apr 8, 2003 1:23 PM
like, say, inner housing lining? The plastic stuff inside cable housings - most internal routing uses this, along with 2 fittings at the entry and exit points on the tube. This way, you get the benefits of housing, but it looks different (I won't say better, depends on your POV).
So, is there a full-length brass tube running inside the top tube, or is it fittings at either end? Is there space around the cable? You can generally slide the inner liner out of a chunk of housing, or if necessary, deconstruct a length. Definitely ask at an lbs, as they may have some liner sitting around from back in the day.
Then just feed a length in, trim it to length, and viola - slippery cables.
If there's no room, then I'm stumped. "Slick" cables would be my only piece of advice. They're drawn through a die after being wound, so the outside is smoother than a standard.
The Gore cables will work, but are a pricey solution, and I found them to not last very long. That was a mountain application, though, and water inflitration killed them.
Good luck.
Pretty much agree with jw25, but.....RickC5
Apr 10, 2003 8:34 AM
1) Never use WD40 as your lube, as it WILL get gummy/sticky as it ages (doesn't take long). I would use a silicone spray, Tri-Flow, or even a bore cleaner (for rifles, watch the paint) as the "cleaner". Then, I would use a pipe cleaner or something similar to really scrub out the tube as much as possible. Even a piece of heavy twine may work if you can manage to thread it through the tube and pull it back-and-forth (thread a piece of monofilament through first, and tape the end of the twine to the end of the monofilament).

2) If you can't use a piece of plastic/nylon housing liner or tubing to run your cable through, THEN apply a liberal amount of bicycle grease to the cable before inserting it into the tube. Yes, its messy and the cable will need to be re-lubed at least once a season.

3) Lastly, you might try to lightly ream out the entry and exits holes with some rolled up, very fine, wet-or-dry sandpaper. This type of sandpaper is designed to NOT lose its "sand" while you use it and is more flexible than the standard garnet paper used on wood. The reason I'm suggesting this is becauce you may have a small burr of some brazing material inside the tube causing the drag. Obviously, if you were to try this, you would have to re-clean and re-lube everything when you're finished reaming.

Good luck!