Need some advice on my MTB Disk brakes

[Bateleur1]

Need some advice from the more clued up Hubbers.

 

What I have:

 

Mtb with stock standard Shimano XT Deore components. (180 disc front and 160 disc at the back)

 

Problem:

 

Very ... I mean very noisy brakes.  I have replaced the disks and pads a couple of months ago which for a time did help but lately the brakes are not in my opinion good and it is so bloody noisy now that my kids do not even want to cycle with me.

 

What I am thinking:

 

Replacing the discs with DEORE XT Ice-Tech brake discs.

 

What I need to know.

 

Resin or Metal?  It seems with the Ice-Tech pads I should go to Metal.  Is Metal in general better than Resin?

 

Should I use the chance to put bigger disks in?

 

If I put in bigger disks what adapter should I fit?

[greg_sa]

I run M785 XT brakes as follows, and they aren't noisy at all:

 

- Discs are the SLX RT-66 model

- Pads are XTR J04C model (metal)

 

That's how I bought the bike, so I've just kept it the same when replacing, and I'm very happy.

[Wannabe]

L, before you go changing rotor sizes, read this article first. Changing to the Ice-Tech rotors is not a bad idea.

In general, resin (or organic) pads are softer and allows better modulation, but it is not as long lasting as the metal pads. Once you changed pads and rotors (at the same time) be sure to properly bed in the brakes. But sometimes, even after they were bedded in properly, brakes gets noisy in wet or moist conditions (like when you are riding in the mist.

 

https://mbaction.com/product-test-shimano-metal-vs-resin-brake-pad-compounds/

[Bateleur1]

L, before you go changing rotor sizes, read this article first. Changing to the Ice-Tech rotors is not a bad idea.

In general, resin (or organic) pads are softer and allows better modulation, but it is not as long lasting as the metal pads. Once you changed pads and rotors (at the same time) be sure to properly bed in the brakes. But sometimes, even after they were bedded in properly, brakes gets noisy in wet or moist conditions (like when you are riding in the mist.

 

https://mbaction.com/product-test-shimano-metal-vs-resin-brake-pad-compounds/

 

Thanks for the article.  So sticking to Resin in my case then not a bad idea.  The moist conditions here are most propably the problem why my brakes are so noisy.  What I can't understand the other bikes which are stored at the same spot is no problem at all.  My wifes city bike (which I use when I help my daugter with delivering newspapers) have over the last couple of months seen more wet and bad weather than my MTB.  Yet those brakes are as silent as the day we got the bike.  Hence me wanting to completely change the disks with something other than what the bike came out with.

[Wannabe]

A lot also depends on the installation of the brakes (pad alignment with the rotors) contamination of the pads, etc.

 

Youtube can give you a lot of info / help on handling this.

[Ashchest]

Noisy brakes are good!  At least I can then hear you behind me and get out of the way quickly! 

[clement]

A lot also depends on the installation of the brakes (pad alignment with the rotors) contamination of the pads, etc.

 

Youtube can give you a lot of info / help on handling this.

 

Agreed, the components you have should not be noisy. Before spending money check:

 

1. Is everything installed correctly and aligned correctly

2. Are all the bolts tightened

3. Are the pads not glazed or contaminated

 

Chances are pretty good it is the above and not the just the components that is inherently noisy.

[Bateleur1]

Noisy brakes are good!  At least I can then hear you behind me and get out of the way quickly! 

 

You won't just hear me, you will propably cr@p yourself if you hear these brakes behind you, like half of Munich did two weeks ago when I was cycling through it.

[Wimmas]

There are a couple of things it can be but maybe try cleaning the rotors with surgical alcohol. You can get the bottle or swabs from Dis Chem for cheap. It rubs off any dirt.

 

Worth a try.

Edited May 2, 2019 by Wimmas

[Hellgate]

Some rotors are brake pad specific meaning for example that metal will not work as they are designed for resin pads only.

[King_Crispy]

It could be that a seal has gone and it's leaking brake fluid onto the rotor. Someone on another thread suggested putting the pads on the stove on a low heat to rid them of excess moisture, and then giving them a light sanding before reinstalling.

Is it both brakes making the same noise or just one of them?

[MORNE]

sounds like glazed pads? resin pads on shimano have been silent for me since forever. metal pads are generally louder than resin btw. 180 front and 160 rear is fine. if you cant stop with xt brakes and those...chances are good your brakes are not properly tuned...bedded etc

 

 

Edit: make sure you clean the discs too with some alcohol...oil ruins brakes

Edited May 2, 2019 by morneS555

[porqui]

clement's post

 

 

Take out the pads and check them.

Undo the caliper bolts and align calipers.

 

YouTube has plenty on servicing disk brakes.

It's not difficult at all.

Edited May 2, 2019 by porqui

[Bateleur1]

Thanks for all the info.  I have order new discs and resin pads.  The Icetech discs of Shimano can take both metal and resin.  The current disks will not get thrown away.  They will be cleaned properly and checked and stored for later.  Will check the calipers as well when replacing.

 

I have seen quite a ideas on how to bed the brakes.  How do you guys do it?

[Bateleur1]

It could be that a seal has gone and it's leaking brake fluid onto the rotor. Someone on another thread suggested putting the pads on the stove on a low heat to rid them of excess moisture, and then giving them a light sanding before reinstalling.

Is it both brakes making the same noise or just one of them?

 

Was more the back brake.  Then replaced both as the old pair of disks was worn after three years.  After replacing the front was perfect but the back always had bit of a noise when applying pressure and getting to lower speeds.  Now it is both that makes one heck of a noise as soon as good pressure on the brakes are applied.

[Jehosefat]

I have seen quite a ideas on how to bed the brakes.  How do you guys do it?

 Find a downhill on the road somewhere, head down it at about 20km/h and brake hard until you are almost stopped (don't lock the wheels and don't actually stop) repeat this a few times and then do it a few more times from higher speed (about 30km/h). Then Robert is your mother's brother.

Edited May 3, 2019 by Jehosefat