Bicycle Mechanics - Dual-pivot brake caliper install?

So I have a nearly-new 2008 CAAD9 frame, which I'm building up with parts off of eBay. Problem is, I've only ridden my cross bike with cantilever brakes, so I'm not entirely sure how some things go on, like the brake calipers.

Each one has 2 serrated washers, and I can't figure out if I need to install both of them. Obviously one goes between the caliper and the brake bridge, but the other one can't go on the other side of the brake bridge because it blocks the blind nut from engaging the mounting bolt. Is there some reason that I might need to stack both of them on the same side of the brake bridge? It seems like using one would yield the same result, and allow greater thread engagement between the nut and mounting bolt.

As long as the recessed nut doesn't bottom out before getting the caliper tight, use only the one washer on the rear face of the bridge. Add a second washer only if the threaded bolt on the caliper or the recessed nut are too long. Even then, getting a shorter nut is preferred.

you only need one serrated washer for each. They're there to keep the caliper from pivoting on its axis.
I think they give you a spare for the next bike they might go onto.

you only need one serrated washer for each. They're there to keep the caliper from pivoting on its axis.
I think they give you a spare for the next bike they might go onto.
Not sure about the dual-pivots, but better quality side pull brakes would often use 2 serrated washers on the front brake to allow the wrench flats on the pivot bolt (used to center the caliper over the rim) to clear the lower headset cup. Maybe it's just an anachronism from back then...

Not sure about the dual-pivots, but better quality side pull brakes would often use 2 serrated washers on the front brake to allow the wrench flats on the pivot bolt (used to center the caliper over the rim) to clear the lower headset cup. Maybe it's just an anachronism from back then...

hmm, that's a good explanation.

I've found it unnecessary to even use a wrench to hold the caliper in place...
just some blue loctite... never had to fix the position of my brakes either.

I've never had to double washer rear brakes but have used the supplied washer plus a 2 mm spacer washer in front to let the brake pads clear the blades of a wide carbon fork.

As long as the recessed nut doesn't bottom out before getting the caliper tight, use only the one washer on the rear face of the bridge. Add a second washer only if the threaded bolt on the caliper or the recessed nut are too long. Even then, getting a shorter nut is preferred.

That's not what the purpose of that washer is for. It's a star/serrated washer for a reason.


Not sure about the dual-pivots, but better quality side pull brakes would often use 2 serrated washers on the front brake to allow the wrench flats on the pivot bolt (used to center the caliper over the rim) to clear the lower headset cup. Maybe it's just an anachronism from back then...

All modern dual pivots (like the ones that come on the OP's bike) that come with those washers are easily centered by hand and not the "centering" bolt.

The purpose of that serrated washer is to prevent dual pivots from rotating by hand easily when the mounting surface sucks. It also serves to move the caliper out for whatever reason(s) already stated in this thread.

That's not what the purpose of that washer is for. It's a star/serrated washer for a reason.

The purpose of that serrated washer is to prevent dual pivots from rotating by hand easily when the mounting surface sucks. It also serves to move the caliper out for whatever reason(s) already stated in this thread.
Yeah, I know what it's for and why but my experience is that the star/serrations have not been needed on any bike I've mouted dp brakes. Snugging the mounting nut firmly keeps them in position and that's all that's needed.

Is it safe to assume that these washers won't damage a carbon frame/fork? They do dig into the carbon a bit, but not very deeply. All my carbon forks have alloy crowns so I don't think there's any structural carbon in that area, but I don't know about full carbon forks.

Is it safe to assume that these washers won't damage a carbon frame/fork? They do dig into the carbon a bit, but not very deeply. All my carbon forks have alloy crowns so I don't think there's any structural carbon in that area, but I don't know about full carbon forks.

as far as I'm aware, caad9 stock fork has an aluminum block in the crown just for this purpose.