sram red 22 brakes do not seem to open wide enough for 27.5mm wide rims

[sowestport]

The problem is actually with the rear. The front has no problem.

Does that make sense? Perhaps my LBS swapped out my rear caliper with an older model?

[MaraudingWalrus]

If the shop you visit seriously gives you the vibe that they're going around swapping parts on your bike, you either need a new shop, or need to be less paranoid.

But, max width on those is supposed to be 31mm or something, so it should clear.

I've seen a couple folks who had brake shoes that contacted the seatstay and prevented it from opening.

I'd suspect that the 31mm is with the pads that come with them, so potentially if you've got different pads, it's possible that they may be thicker than the sram pads.

Also try cleaning them, if they're used, I've seen some schmutz caked up in there stopping one from opening all the way.

[sowestport]

But isn't it strange that the front calipers have no problem but the back ones do?

I just changed the brake shoes from front to back to see if pad wear (although almost new) had an effect, but there was no difference.

The rim width is the same for front and back.

[sowestport]

I temporarily solved my problem by removing a set of washer. These are the inner washers of the brake shoes. I hope this doesn't do damage.

I attached a pic to make this clear and hopefully will affirm that I'm not doing something to damage the shoes.

[ergott]

Don't remove those.

[eBAUMANN]

Don't remove those.

agreed...do not remove.
also, is it just me or is that washer on backwards in that stock photo...

[sowestport]

No they are not on backwards. The flare part actually sits into the brake shoe and actually sits on the structural part within the shoe. But given that it does sit onto the structural part and the washer is so thin, I feel that there is not that much force. Without the washer, the force is now on the body of the brake shoe. The flat part of the washer is for the blades of the caliper, which are also flat.

[-dustin]

Pads hitting the inside of the seatstays?

[thunderworks]

If your generation of Red brakes has the 2.5mm allen screw fitting on the top of one arm, make sure it's not screwed in and constraining the range of motion on the caliper arms.

[sowestport]

Pads hitting the inside of the seatstays?

No they don't. Is the primary purpose for the inside washers for spacing?

[sowestport]

If your generation of Red brakes has the 2.5mm allen screw fitting on the top of one arm, make sure it's not screwed in and constraining the range of motion on the caliper arms.

I'll check it out. I thought the 2.5mm screws were for centering as they just provide more or less tension on the springs. I didn't think they restricted the range of motion.

[sowestport]

I'll check it out. I thought the 2.5mm screws were for centering as they just provide more or less tension on the springs. I didn't think they restricted the range of motion.

Oops. I have two 2.5mm screws on either side of the brake. Are mine the later generation?

[-dustin]

No they don't. Is the primary purpose for the inside washers for spacing?
No, it's to help with aligning.

What rim are you using?

Do they have trouble even with the cam open?

The 2.5mm screw that would help is for non-Aerolink brakes. It would open the calipers, but Red22 never had that style of brake.

[sowestport]

No, it's to help with aligning.

What rim are you using?

Do they have trouble even with the cam open?

The 2.5mm screw that would help is for non-Aerolink brakes. It would open the calipers, but Red22 never had that style of brake.

My rims are the new Enve 3.4's, which have an outside width of 27.5mm.

Yes I have trouble even with the cam open. I don't have this problem with the front brake, though.

So it seems the washer is to align the pad for toe-ing in or out so as to eliminate shudder and noise?

[ergott]

Both washers are for getting the pad flush with the rim (I never bother with toe).

[-dustin]

My rims are the new Enve 3.4's, which have an outside width of 27.5mm.

Yes I have trouble even with the cam open. I don't have this problem with the front brake, though.

So it seems the washer is to align the pad for toe-ing in or out so as to eliminate shudder and noise?
Hm. That's odd. I've run multiple "year models" of Aerolink brakes with all of Enve's rims and never had an issue. Can you post a picture?

What happens if you release the cable from the brake calipers completely?

[sowestport]

Hm. That's odd. I've run multiple "year models" of Aerolink brakes with all of Enve's rims and never had an issue. Can you post a picture?

What happens if you release the cable from the brake calipers completely?

I can get pics tomorrow.

I have released the cable completely. And I have tried to pry the calipers further open while the cable is not even attached, but they don't open wide enough.

[ColonelJLloyd]

27.5mm is pretty wide for a rim brake rim. I wouldn't be surprised to see issues like this arise from rims wider than 24mm on a lot of bikes. Even if the calipers clear, when they are that close modulation is subpar.

[-dustin]

I can get pics tomorrow.

I have released the cable completely. And I have tried to pry the calipers further open while the cable is not even attached, but they don't open wide enough.
Take the brake off the bike, if you're comfy doing that, and put it up next to the front and see if anything looks different.

[cachagua]

How long does a brake pad last you? Couple of seasons?

Here's why I ask: I had a similar problem, and solved it by removing enough material from the pads to get clearance. It ended up being about half the (visible) thickness of the pad. If this doubles the frequency of needing new pads, *yawn*...

I rough-cut the pads with an exacto, and sanded them smooth with 80-grit paper on a block. Wasn't too difficult.

Although it is still a weird mystery why one brake does this and the other doesn't!

[shovelhd]

27.5mm is pretty wide for a rim brake rim. I wouldn't be surprised to see issues like this arise from rims wider than 24mm on a lot of bikes. Even if the calipers clear, when they are that close modulation is subpar.

I've been riding 27.5mm wide rims for years with DA9000 brakes and Black Prince pads. Never an issue. Plenty of clearance. Excellent modulation. This is a SRAM problem.