Poor rear brake performance

Essex Man

I re-cabled my 2 year old bike the other day. One of the things I was hoping to solve was poor brake cable performance, often resulting in slack in the cables which needed to be taken up by the brake levers before the callipers moved.

However, I found that for the rear brake the problem persisted after re-cabling. Eventually I worked out that this is due to the stiffness of the cable lining running from the calliper to the frame, as when the cable lining was removed from the stops the calliper performed fine as the lining was no longer obstructing movement.

I think the cable was cut to the appropriate length, as per the pictures on Sheldon Brown.

Could it be that the spring is no longer strong enough? The are pretty low spec tektro brakes on a Giant Defy 3.

Thanks.

Rodrego Hernandez

Could be. Try taking the spring off and bending it straight a little to increase it's pull. Make sure the cable is smooth and that the pivots are free-moving.

Essex Man

Will do, thanks.

Monty Dog

Make sure there aren't any tight bends / kinks or you've compressed the outer at any point too

amaferanga

Did you tidy up the cable outer ends with a file?

antfly

I have the same problem on my winter bike, the only thing that helps is cleaning the brake with muc-off and water but it still sticks a bit and as soon as it gets dirty again it worsens. I just changed the cable outers as well, didn't help much. I took an old brake apart once and that didn't help and was a real faff, wouldn't recommend it.
I should add my problem is with the calipers not opening properly.

rhext

Assuming you've got the cable nice and tight to start with, It sounds like the inner isn't moving freely through the cable outer. This could either be due to accumulated grime in the outer, or if there's a kink or obstruction of some sort (as amaferanga asks, are the cable outer ends cut nice and clean?).

If you're re-using the old cable outers, check them carefullly to make sure they're sound and that they're cut clean (take the ferrules off the ends and use an old spoke or something similar to make absolutely sure that they're not crimped slightly where they were cut). Then blast some GT-85 through them to clear out any crud and try again.

Alternatively (and perhaps preferably) get some new cable outers and refit! Also check that the calipers themselves are moving freely, as they can get sticky over time. If it was the spring, I'd expect them to pull easily and then not release cleanly!