Road bike brake Arches - pad rub against the rim

[koukie]

I have I think its Shimano 105 arches on my Giant TCR. I cant seem to "centre" them properly, they always tend to go to one side then the one pad rub against the rim. Am i suppose to tighten them somehow so that they stay in the middle, I see there is a nut that I can turn just behind the arches but that does not seem work? The back wheel seems to be fine.

 

Any advice?

[DBK]

This is a constant problem for me as well. Sucks eh?

[droo]

Two ways of doing it - one is to tighten them correctly centred, which can take a bit of practice. The other is to fine-tune with the screw on the top of the caliper.

[Johan Bornman]

Shimano brakes are dual pivot brakes. Dual pivot brakes cannot centre themselves and are not spring-loaded so that they can follow a buckled rim.

Campagnolo rear brakes are single pivot and can centre themselves (within reason) and can follow a buckled rim without getting in the way.

 

Dual privot brakes need careful adjustment so that both pads contact the rim at exactly the same time. If not, they will move the rim over to one side, thereby slackening the spokes on that side and potentially, the nipples can shake loose.

 

They are adjusted using a screw as Drew above said. Unfortunately this adjustment screw on Shimano is really crappy. Try using a flat screwdriver rather than the Philips. It will slip less.

 

On Campag, this screw is a 2mm allen key - nice.

 

Note that these adjustments don't open or close the caliper - that's done via cable tension. The screw merely keeps the jaws in their position relative to each other but moves them over to the left or right - both at the same time. Also, as Droo says, you can also centre them using the anchor bolt and of course you should do the large adjustments there. The adjuster is merely to fine-tune it.

 

 

 

Here's the Shimano adjustment screw. You can clearly see why a flat screwdriver works better. I think the Philips head is completely fake.

Edited July 25, 2013 by Johan Bornman

[SL7]

Well said JB