I have sintered Nukeproof pads in Sram Guide Rs and the brake performance is quite poor. They have been bed in, and about 8 hours use. I wonder if it is due to an issue with the pads/rotor? In the pic you can see they’re slightly scored and have an odd wear pattern to them (the dark area). Is the dark area glazed due to overheating, or is that appearance normal?
[url=https://flic.kr/p/Vsdoc1]IMG_0272[/url] by mightyjcb, on Flickr

Below is a section of the rotor after a wipe with isopropanol, again scored but can barely feel it with a nail. Note the bright/dull area of braking surface corresponding to the pad wear.
[url=https://flic.kr/p/VQQ5hv]IMG_0274[/url] by mightyjcb, on Flickr

The brake doesn’t feel spongey, but i bled it anyway (6 months old).
I sanded the pads in a figure 8 shape in attempt to restore the surface and keep it flat:
[url=https://flic.kr/p/VQQ5vg]IMG_0273[/url] by mightyjcb, on Flickr

Thought i’d post up to see what others thought before i start the bed in process.

I just pretty much the same thing. Brake was working ok, but when I took the pads out I had a very similar wear pattern to yours. When I looked at the disc the middle has worn right down to the point you could see and feel a groove. Binned the disc and sanded the pads. Will see if its any better later today.

Were the rotors new when you installed the new pads ?

You might just need to do a good wet ride in the Dark Peak somewhere 😉

Looks like glazing from overheating- do you drag the brakes?

Also it could just be the photo but there appears to be some discolouration on the disc spider ,again could be heat?

They look glazed to me. You’ve sanded the glaze from the surface, so I suspect they’ll work much better now.

What size are the rotors? Larger diamater rotors will be less susceptible to overheating. Or you could try not dragging the brakes so much (If that’s the issue).

The rotors are 6 months old. I rode Bikepark Wales in the wet after bedding the pads in, though the rotors already had the wear shown.
The discoloured area on the rotor is just in the picture – reflection/shadow.

Rotors are 200mm.
Don’t think i drag brakes, i’ll be more conscious about braking style after i’ve bed them back in.

Hands up to dragging brakes here (Guide R’s).

Still don’t get the pads looking like that though.

I’m using Uber pads, can’t remember compound though.

Not resin only (OEM?) discs/rotors are they?

cheap pads? Buy decent ones from someone with a record of making them – either originals or EBC or another company that actually knows about brakes.

I think the Guide Rs are supplied with resin pads. It was with the resins that i noticed the decreased performance and odd ‘wear’ on the rotor.
Had a quick look, nothing on the rotor stating resin/organic only.

Nothing to do with cheap pads.

I’ve got the same with race matrix pads that were amazing to start with. I’ve sanded pads but it has reappeared. Suspecting either dragging of brakes (guilty) And contamination (guilty to a lack of thorough cleaning)

Try another disc.

The only real way you can be braking on inner and outer edges but not in the centre of the track is if the centre is lower than the edges. If it was only one edge it might’ve been calliper/mount alignment but to brake at both extremes of the track and not down the middle it has to be a poor disc.

After a bit of bedding in.
[url=https://flic.kr/p/ULhVXS]FullSizeRender[/url] by mightyjcb, on Flickr

Rear brake has same issue, though not as severe. Perhaps new rotors it is.

Bedding in is a myth, you need to read up on the web about pad material transfer to the rotor, which has to happen before the brakes work really well.

Check out the posts by Yellow Saddle, a bike mechanic, on this forum thread:

https://www.cyclechat.net/threads/pulsing-disc-brakes.214507/#post-4690194

Sintered pads. They’ll glaze easily. And squeal a lot.

Try kevlar or standard organic.

And yes, with bedding in, it’s not the pads, it’s material on the disc that’s key. Each time you do a proper clean of the disc, you have to wait until the disc is coated again before they’ll be working well.

Question for the Guide users in here, do your Guides squeal in the wet or after a clean? Mine howl so bad with even a hint of moisture on the ground, they still work, but the noise isn’t pretty!

Ive heard swapping the discs to Shimano Icetech resolves this?

@oikeith I can definitely tell you that a full Shimano IceTech setup – finned metal pads with IceTech rotor will make annoying noises at the slightest bit of wet on the rotor. The only way to make them stop in the wet is to warm them up and keep them warm if they’re still getting wet/cooled.

Shimano non metallic pads are no better and just get destroyed in proper wet rides so not good value.

The Shimano metallic pads do last a very long time though. Best value for money I’ve had with any pads but they are shockingly expensive.

Never had a totally silent in wet conditions brake setup. Moved to Shimano after Avid Elixers though as anything is better than those.

Never tried Guides.

Never had a totally silent in wet conditions brake setup.

my Hope X2 Evo with resin pads never make so much as a peep in any conditions

Kevlar has been best solution for me. Harder wearing then standard organic, but way less squeal than sintered. Doesn’t matter the brakes, it’s the pad compound. Sintered pads have metal in them. Metal on metal + water = squeal.

All pads squeal though, but sintered is by far the worst for me.

Been running Kevlar for ages but ran out (thanks Superstar) and had to resort to sintered I’ve had lying around, and it’s annoying the hell out of me. Even in the dry it’s making a racket.

I had some very lightweight rotors that were mainly made of air, and the middle part of the swept area of the discs and pads got butchered, plus the brakes felt and sounded as though they were grinding horribly.
I now only use Shimano discs now as they wear the pads evenly, due IMO to an even distribution of holes across the swept surface.

Don’t think i drag brakes

Everyone drags brakes, you just don’t realize you are doing it. Don’t think of it as a fault, we have brakes so we can bleed off speed whenever we need to.

hols2 – Member
Don’t think i drag brakes
Everyone drags brakes, you just don’t realize you are doing it. Don’t think of it as a fault, we have brakes so we can bleed off speed whenever we need to.

Oh, you’re going to get tarred and feathered for saying that!

(Not be me,I tend to agree with you…)

I had some very lightweight rotors that were mainly made of air, and the middle part of the swept area of the discs and pads got butchered, plus the brakes felt and sounded as though they were grinding horribly.
I now only use Shimano discs now as they wear the pads evenly, due IMO to an even distribution of holes across the swept surface

Looking at the pictures I think that’s what is going on here. Due to the design of the disc there is hardly any material in the main braking area of the disc so what little is there just gets hot.

Never had a totally silent in wet conditions brake setup.

Oddly my Magura MT2’s with sintered pads ‘gobble’ in the dry, yet a touch of wet and dirt and they are silent…

The Guide + sintered setup on my bike doesn’t squeal or howl on a ride, at all – silent. I get squeal when i brake after the bike has been washed and so water on metal rotor and metal pad. When its dry after a few mins its back to silent. Seems to be a different experience to what others have posted here.

Kevlar has been mentioned, that compound is an option if mine are glazing. Though i may score any pad if my rotors are part of the problem here.

oldnick – Member
I had some very lightweight rotors that were mainly made of air, and the middle part of the swept area of the discs and pads got butchered, plus the brakes felt and sounded as though they were grinding horribly.
I now only use Shimano discs now as they wear the pads evenly, due IMO to an even distribution of holes across the swept surface

MarkBrewer – Member
Looking at the pictures I think that’s what is going on here. Due to the design of the disc there is hardly any material in the main braking area of the disc so what little is there just gets hot.

This sounds logical. I would’ve though others might have experienced this though? Aren’t these rotors used on quite a few Sram brakes over quite some time? Should i try Shimano rotors? Different quality metal?

I rode today and consciously tried to not drag the brakes. I believe everyone drags 😀

Had 2 sets of Guides and never had any problems with braking power.

Mk1 guide rs used to chew through resin pads so I always used sintered. Rarely made any noise whether wet or dry and regardless of the make of sintered pads (used Sram and uberbike). That bike had 160mm centreline discs.

Now got the new version the Guides with the s4 calipers on 200/180mm discs with standard pads which I presume are resin. Get a bit of ‘gobbling’ with these when using them a lot going fairly slowly on very steep downhills. That’s in the dry – haven’t really used them in the wet yet. Going to bleed the front brake soon as the lever is mushy and hacexa look to see what pads are in there. Doubt when I replace them that it’ll be resin ones again. Probably get some uberbike ones – not sure which compound yet.

Does anyone know if the mk1 and mk2 pads are the same?

joebristol – Member
Had 2 sets of Guides and never had any problems with braking power.

Mk1 guide rs used to chew through resin pads so I always used sintered. Rarely made any noise whether wet or dry and regardless of the make of sintered pads (used Sram and uberbike). That bike had 160mm centreline discs.

Now got the new version the Guides with the s4 calipers on 200/180mm discs with standard pads which I presume are resin. Get a bit of ‘gobbling’ with these when using them a lot going fairly slowly on very steep downhills. That’s in the dry – haven’t really used them in the wet yet. Going to bleed the front brake soon as the lever is mushy and hacexa look to see what pads are in there. Doubt when I replace them that it’ll be resin ones again. Probably get some uberbike ones – not sure which compound yet.

Does anyone know if the mk1 and mk2 pads are the same?

Did your MK1 Guide RS chew up pads like the pictures posted? Interesting that sintered pads were unaffected – My issue could be different to yours.

My Guide R setup came on a 2016 Canyon (200/180mm), so guessing the Mk1 Guide? Though the pistons are of unequal size which i have read to be one of the updates for the S4 caliper..Either way, S4 or not the pad wear i have is odd to me and probably causing the loss in performance.