Bicycle Mechanics - Adjusting dual-pivot brakes

I'm trying to adjust the Ultegra dual pivot brakes I recently purchased. This being my first road bike, I'm only used to cantilever/v-brake type systems. On those, as you know, you adjust the toe-in. I can't seem to do that with the Ultegras. The front pads are pretty even, but on the rear one pad has significant toe-in and the other has none, almost toe-out by the appearance. When I try to adjust the toe-in, the pads revert to the old settings as I tighten them. I can easily lock the rear wheel while rolling along slowly (700x23 tires, not a lot of rubber). At slow to moderate speeds, I can put enough force into the front brake to lift the rear wheel off the ground. However, it bugs me that the rear pads are so out of adjustment compared to what I'm accustomed to seeing. Compared to V-brakes and disc brakes, I'm used to much more braking power up front. The brakes just don't feel as solid as those on my mountain bike.

I don't have any odd noises, squealing, etc. Is this just how road bike brakes work or am I missing something? How do you adjust toe-in if you don't have the little stack of cupped washers like those on v-brakes?

Thanks,
Chris

There should've been some cupped washer, the other way to do it is start filing (this won't work if the error is large). For example the Kool Stops cartridge pads with holder have this.

Can I use the cupped washers from a set of v-brakes?

Chris

My Ultegra brakes have a cupped washer system. Now, it's not really a true cupped washer. The brake pad cartridge, the metal piece that holds the rubber pad, has a raised circular section where the bolt attaches. That should give you some adjustment. The picture should make that clear. That rounded curved part should give you more than enough range of movement to adjust the toe in.

If the brakes are moving out of position while you tighten the screw, put something hard (but something that wont scratch or dent your rims) and thick enough against the brakes as a shim to give you the needed toe in and apply the brakes against the rim. Make sure everything is aligned and toed properly Tighten the pad holder bolts. The pressure against the rim should prevent the brake pad holders from moving while you tighten.

To address the feel of less braking power, part of the learning curve going from an MTB to a road bike is the speed. You are going faster, so you your braking distance is longer, giving the perception of less braking power.

Mach42: The backs of my pad holders are flat, there's no mechanism as shown in your drawing. There's now way I can see to affect the toe-in of these brakes as they were shipped (OEM packaging in sealed baggies).

Chris

Here are the brakes in question:

http://www.cambriabike.com/Images/product/shim_ultegra_6500_caliper.jpg

Chris

Mach42: The backs of my pad holders are flat, there's no mechanism as shown in your drawing. There's now way I can see to affect the toe-in of these brakes as they were shipped (OEM packaging in sealed baggies).

Chris


Toe in/out adjustment is something that's only been added to the Shimano Ultegra brakes in the latest model. My previous model (6500) don't have any toe in/out adjustment on them either. In the old days with single pivot brakes we used to just bend the arms to get the toe in right. I'm not sure if you wan't to do that with modern dual pivot brakes.

Yes mtn v-brakes are stronger than road brakes but you do get used to them. I've fitted some Koolstop Salmon pads to my Ultegra brakes and it decreased the effort required for braking quite significantly.

EDIT: you just posted a picture while I was typing. Yes they're the 6500 model that came without any toe in adjustment.

Regards, Anthony

Thanks Anthony.

Is there any problem with filing on the back of the holder to change it's profile and hence it's positioning as Operator suggested above?

Chris

Thanks Anthony.

Is there any problem with filing on the back of the holder to change it's profile and hence it's positioning as Operator suggested above?

Chris

I can't realy say if this is a good idea or not. Even though its a little anoying personaly I would just leave it as it is. 99% of your braking is on the front wheel anyway with a road bike and the rear brake is realy an emergency brake if something should fail with the front brake or you get a front tire flat. So if there's no squealing or hammering then just leave it. If you wan't a better feel on the lever and to use less force to brake then get some Koolstop Salmon brake pad inserts although I've seen brake test charts that show that when it comes to ultimate braking force the hard pads are good even though they feel dead.

Regards, Anthony

Thanks Anthony.

Is there any problem with filing on the back of the holder to change it's profile and hence it's positioning as Operator suggested above?

Chris

Honestly, I think you'd be better off just picking up a new set of holders and kool stop pads - your braking performance will be ultra awesome and you'll have toe adjustments.

My LBS suggested bending the arm. I did this with good results. Just used a cresent wrench and tweaked it out a bit.