Bicycle Mechanics - Brake cable rattle

I have an odd rattle in my left hand shifter/brake. The unit is a 2001 Dura Ace STI shifter and brake unit. I installed it myself. The noise sounds like a barbque igniter, kind of a high pitched ting. It only occurs on rough roads at high speeds. I am pretty sure that I tracked it down to the brake cable as it enters the shifter. The brakes work fine but I guess the cable housing is either not all the way in, or it is hitting on something. Does anyone have any ideas, or know of a picture diagram or schematic that shows how the cable housing should contact inside the shifter?

Thanks,

Don

The cable casing is very unlikely the problem in that it instals without a ferrel on the end of it into a circular hole in the back of the shifter,without stripping any of the casing..Clearance is tight enough that there is little or no room for it to move. If it was not seated fully into the hole you would have noticable sloppy brake performance but it would still not rattle.The cable is further secured by taping it in place prior to applying the bar tape.

Could the internal brake handle return spring or its affixing screw be loose?

are you sure it isn't the bare cable slapping against the frame? the sound you describe is exactly the same. if a segment of bare cable parallels the frame, it will make that sound at high speed on bumpy roads. the solution is those little nylon "doughnuts" that insulate the cable from the frame.

Originally posted by Bandit
are you sure it isn't the bare cable slapping against the frame? the sound you describe is exactly the same. if a segment of bare cable parallels the frame, it will make that sound at high speed on bumpy roads. the solution is those little nylon "doughnuts" that insulate the cable from the frame. I had one routed inside a frame that would do it too.Solution was outsidde routing and securing with nylon ties.

I checked the bare cables against the frame that does not appear to be the problem. I have the little donuts installed as well. It may be the return spring as mentioned previously, I can replicate the sound by bouncing the bike. When riding it will do it with my left hand on the top of the bar or on the hoods but it will if I am in the drops. I really only noticed this past weekend on a 35+ mph desent on a rough road and I though at that time is was the carbon fork, so it slowed me down quite a bit. I guess I am going to have to unwrap the bar and check it out. You know the cable protector things that are supposed to be cover the cable housing as it runs under the bar tape, that piece has a metal flange end on it, I think that may be the culprit. I probably don't need that piece anyway.

Originally posted by DonTx
. .....I probably don't need that piece anyway. You are right about not needing the piece. As for the return spring possibility,don't go taking the levers apart unless you know what you are doing.