Hi all,

A basic question.

I'm trying to center the brakes on my bike. I checked out a couple of YouTube videos, both of which say it's a rather simple procedure on these Shimano brakes. Insert Allen wrench, adjust, voila.

However, the Allen nut on my brakes is in a different spot than on the video. Okay – just a different model, I assume. My brakes are about ten years old. But before I assume I'm correct, I thought I would post a picture and solicit the views of others.



The Allen nut in question, of course, is in the right-center portion of this photo. It takes a 4mm wrench. Is this the one that will allow me to center the brake calipers?

BTW – yes indeed, these need cleaning. I rode in some wet weather the other day.

I've found that the easiest way to center dual-pivot brakes is to loosen the main mounting bolt (actually, allen nut), squeeze the brakes together and re-tighten.

The one in the picture is one arm pivot, don't mess with it..
as above the Mounting bolt on the other side
is what you loosen and retighten to center dual pivot sidepulls.

In your photo there is a Phillips headed machine screw just above the mentioned 4mm allen bolt. This is the screw that centers the pads by making one arm move inor out and the other arm follows. But having said that I do as Eric S said. Loosen the nut that holds the brake onto the frame, rotate the caliper so the pads are contacting the rim equally and retighten. Pull the brake lever and see if the pads contact at the same time, repeate if not. The screw I first mentioned has a narrow range of centering and as it does that the pads will change their height on the rim. Brake adjustments are often a process of doing a bit of this , then doing that and going back to this untill all is good.

As others have mentioned, the allen nut is the recessed bolt on the other side. But usually for most dual pivot calipers like the ones the OP shows, the main allen bolt on the seat stay bridge is for bulk centering. We use this to orient the calipers near center and tighten. The fine centering can be done with a small allen or flat screwdriver on the recessed center set screw on one of the caliper arches. However, if the brake anchor bolt is correctly torqued and not over tightened, you should simply be able to rotate the arches slightly left or right and center them. Then squeeze the brake lever and suddenly, the brakes should be relatively centered. No tools needed.

+1.

This is how I center my brakes. Also, I once saw Alberto Contador center his rear brake this way just before starting a stage on the Giro or TdF, I don't remember which.

As i said the problem on relying on this fine centering screw is that it also changes the pads position WRT the rim side walls. How many of you who have said to use this method to center the brake have also mentioned this detail? If the adjustment is pretty small then this fine adjustment screw is good to go. But the problem with this method of teaching (reading forum replies) is that the small details are lost in the static, people believe what they think is the simple way out. So unless the full picture is explaned the info is incomplete. Sorry to sound harsh but the fine points matter when you get paid for this stuff. Andy.

I think you need to clarify that dual pivot calipers will not undergo change in ultimate pad position relative to the rim upon contact. The small set screw only changes the width between pads. The change in ultimate position only happens with brake shoe wear. The side pivot shoe will ride higher on the rim.

But that really not that important. Dual pivot sidepull calipers are darn easy to adjust. There is rarely a need to use the fine set screw and in the field, it is more than fine to simply use hands to adjust.

Or am I wrong here?