Shimano XT brake pad wear issue

[El34]

I have had my 2012 Yeti SB95 for 1 year and I decided to some brake maintenance today to see how the pads looked and de-glaze the rotors.

The stopping power has gone down quite a bit since the bike was factory fresh.

The rear is 160mm the front is 180mm rotor

The rear pads looked good, no problems there. Even wear across the whole face of the pads

There seems to be a problem with the front caliper mount. It is not sitting down all the way and using all of the brake pad surface.

In the past, I did notice that the complete rotor surface was not being used but did not know how bad until I saw the pads.

If you look at the picture you can see how much of the pads are not contacting the rotor surface.

The bike shop that assembled the SB95 Yeti used the cup type washers.
Did they use the wrong washers?
It looks to me like the caliper needs to drop down about half the height of the cup washers.

On my Avid juicy bikes these washers work fine, but these are my first XT brakes and I am not familiar with what they need to be mounted correctly.

Check out the photos and look how much more pad I could be using.
I included a side view of how the calipers are mounted and a picture of the 180mm adapter being used.

[irv_usc]

as far as i know that is mounted wrong. the washers you have can be used but they are supposed to be on the high side of the caliper.

[Bailey44]

Yep, there shouldn't be any washers right there. Either that or all my bikes are set up wrong.

[irv_usc]

btw i bet you are losing braking power because the unused portion of the pads are now touching and keeping the braking surface from pressing onto the rotor fully.

[knoob]

Those are Avid washers........take em off. The only washer should be the black one. Probably be beat to start with new pads.

[dharel1705]

As others have said, take the washers and cups out. They are for AVID brakes that use Caliper Positioning System (CPS) hardware. The black washer under the bolt head is OK. Those pads are shot. Also, find a new shop.

[El34]

The shop was Jensen.
I mail ordered the SB95 a year ago.

I bet they had a problem getting the brakes set up and so they reached for the cup washers to solve the issue. Maybe they let a newbie shop guy help set up the bike?
The rest of the bike was set up perfectly so who knows?

I have a new set of pads. I'll remove the cup washers and see how the pads sit on the rotor.
I'll report back tomorrow

thanks for the info

far as i know that is mounted wrong. the washers you have can be used but they are supposed to be on the high side of the caliper.

I know that is not correct. They don't do anything on the other side of the caliper next to the bolt head. The deal with cup washers is to be able to tilt the whole body of the caliper to compensate for mounts that are not perfectly parallel with the rotor vertically

[madskatingcow]

The washers are needed, just on top of the caliper - that's all you have to change.

Pictured a front 180mm Shimano Adaptor SM-MA90-F180P/P - washers are included.

[irv_usc]

What he said. Here's a pic of my front brake. My other bike that had a boxed version also has the same washers.


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[Learux]

If you thought you brakes where good before. You are going to like them now!

[Berkley]

I know that is not correct. They don't do anything on the other side of the caliper next to the bolt head. The deal with cup washers is to be able to tilt the whole body of the caliper to compensate for mounts that are not perfectly parallel with the rotor vertically

Shimano seems to indicate that these are necessary, and goes as far as to include them with the brake mounting hardware. Do they actually serve a purpose? Who knows. I installed them on my brake sets just in case (above the caliper).

[El34]

Weird.

I don't see what the washers can do on top like that because you are forcing flat surfaces against each other.

The bottom on the caliper is flat and so is the 180mm adapter surfaces.

So why have cup washers on top?
Maybe they only serve as spacers for bolts that may be too long.
Maybe they are needed for certain calipers and not others?

[dharel1705]

Never mind.

[madskatingcow]

WRONG!!!!!! The washers shown in the pic are for Avid brakes. They are not used or needed on Shimano brakes.

So the washers in the box of a Shimano adapter, are in fact meant for Avid brakes? Where's the logic

[El34]

But, they are not installed on all XT brake calipers so it makes no sense.

Let see some pics of stock bikes with XT calipers that don't have the washers

[knoob]

This brand new adapter I have is without those.

[El34]

This is mechanical logic.

The washers can't tilt the calipers when they are on the bolt head side.

So maybe some brake bosses are shorter than some and the washers are needed?
Maybe some 180mm adapters are shorter.
Maybe they are for 203mm rotors?

[Berkley]

Like I said, it doesn't make total sense, but here they are in the tech document: http://bike.shimano.com/media/techdo...9830817097.pdf

Note that they are not pictured in the tech doc for the rear brake: http://bike.shimano.com/media/techdo...9830817099.pdf

The only reason I could think of to use the washers is so that Shimano can use the same length bolts on all rotor sizes. In that case the washers don't necessarily need to be concave/convex.

EDIT: The installation instructions make no mention of this: http://bike.shimano.com/media/techdo...9830780951.pdf

[El34]

I think this post on another forum makes sense

The conical washers are not for adjusting the caliper. They go under the head of the bolts to make up for the lack of a flat surface under the bolt head due to angle the mount puts the caliper at.

That would make sense if the bolt was causing the caliper to go out of whack when you tightened the bolt down

Do Shimano brakes need "conical" washers « Singletrack Forum


I'll switch the washers to the topside in the morning and see what happens

[irv_usc]

I think this post on another forum makes sense



That would make sense if the bolt was causing the caliper to go out of whack when you tightened the bolt down

Do Shimano brakes need "conical" washers « Singletrack Forum


I'll switch the washers to the topside in the morning and see what happens

I was going to say that. I think the conical washers ensure that the force of the bolt is evenly distributed on the brake caliper.

For the other poster, the washers came with the front caliper, not with the spacer.

[cobba]

I'll switch the washers to the topside in the morning and see what happens

To get full pad/rotor contact the pads will need to be flat and not have a step on them.
You'll need to grind down the unused parts of the pads or that unused section of the pads will be the only part of them that will contact the rotor.

The bike shop that assembled the SB95 Yeti used the cup type washers.

You should show your pads to the idiot at the bike shop who installed your brakes and explain that your sudden loss of brake power from incorrectly installation almost ended in disaster.


Correct installation for the SM-MA-F180 P/P2 post mount adapter:

http://techdocs.shimano.com/media/te...9830667774.PDF


These concave/convex washers are needed when using a 180mm pm to pm adapter because the topside of the brake caliper won't be flat against the underside of the bolt head



Without these washers the bolt head won't clamp down on the brake caliper with all of it's surface.

Like I said, it doesn't make total sense, but here they are in the tech document: http://bike.shimano.com/media/techdo...9830817097.pdf

Note that they are not pictured in the tech doc for the rear brake: http://bike.shimano.com/media/techdo...9830817099.pdf

The only reason I could think of to use the washers is so that Shimano can use the same length bolts on all rotor sizes. In that case the washers don't necessarily need to be concave/convex.

EDIT: The installation instructions make no mention of this: http://bike.shimano.com/media/techdo...9830780951.pdf

The washers are only used with the SM-MA-F180 P/P2 post mount adapter.
Tech doc 1 shows the SM-MA-F180 P/P2 post mount adapter, tech docs 2 & 3 don't show the SM-MA-F180 P/P2 post mount adapter.

[goodmojo]

to OP thanks for posting. I converted from elixir brakes almost a year ago and I had the washers under the caliper too. I had the same wear issues. The brakes worked great even though I wasnt getting full power. I went ahead and took out the washers and replaced the pads just now.

[El34]

I am off to the shop to fix mine also.
I have a new set of pads as backup in my pack so I am good to go

You should show your pads to the idiot at the bike shop who installed your brakes and explain that your sudden loss of brake power from incorrectly installation almost ended in disaster.

Cobba,
I mentioned a few post up that it was Jensen. I mail ordered the Yeti a year ago.

[cobba]

I mentioned a few post up that it was Jensen. I mail ordered the Yeti a year ago.

They should be told about it, send them a email with a photos and that Shimano techdoc I linked, tell them about how the brakes were setup incorrectly, they became dangerous and could of resulted in disaster.

[El34]

I may do that just in case they are still doing it to other customers.

Success, I just got done fixing the brake pad issue on the Yeti.
All looks good now

After de-glazing the rotors and getting the pads right I can tell just sitting on the works stand that they feel better

I'll give em the big test on my Sunday ride tomorrow