Sram Guide ultimate and floating rotors

foo606

Well having replaced the sticking Guide r with Ultimate and no problems .Until I changed rotors To Clark floating rotors .Silent in operation for 45 miles then brake chatter from rear .
Pads are Sram Oe rear and N+T ceramic front .
I had descended a 1/4 mile at 25 mph .Brakes applied all good .
20 mind later the rear started the chatter noise .its like a lolipop stick touching the spokes .
Anyone know whats the cause .
Thanks guys .

lemonenema

Not sure off the top of my head. First thing Id do is check the caliper hasnt come loose on its bolts. Then take the wheel off and check that the brake rotor bolts havent come loose and theres no warpage in the disc.
Next thing Id do is remove the pads and inspect, press the pistons back in refit the pads and refit the wheel, try braking again and see if its gone, if not try re-centering the caliper,

swod1

The Sram caliper isn't catching on the rivets of the clark disc?

This is one of the reasons hope redesigned there floating discs to work with other brands of brakes.

Just hope I don't have something similar as I have a set of hope floating discs I picked up for a good price to fit to my bike to work with xt brakes.

one thing you sure its not spoke tension issue on your rear wheel?

foo606

No Crossmax pro 29 wheels are good .Its only when Im on the bike under braking conditions .
It did make a slight noise under hard cornering .Im going to check the pads for glazing .
Bolts were tight .I have recentered it but still the same .
I will be taking to Lbs as the hose on rear needs shortening .And going to replace outer and inner gear cable for teflon .
If it continues see what LBS says .
Some say its rivets catching caliper post .But on the workshop stand theres no noise at all .

swod1

Thinking about it I had one of those similar shaped discs on my bike on the front had to get rid of it due to juddering under braking was just awful. Making my forks feel like the bushes were worn etc.

I don't think some shaped rotors are any good and actually create problems as the pads don't align up or have much contact with the disc due to the cut outs on them.

Make sure the caliper alignment is central to the disc etc but you will or should have checked that when looking for and adjusting any brake rub etc.

foo606

There was no brake rub when the disc was installed .
Started happening 45 miles into a ride .It may be brake pad issue which I will inspect later for Glazing .But its odd that everything was peaceful before .
Lets see what a pad change does .
After that Im at a loss .May have to remove and replace with Solid Sram centerlines .

billycool

I run Clarkes rotors with both SLX and XT brakes with no issue. I also run Clarkes sintered pads F&R.

No idea what your specific cause could be, unless something is loose/catching.

Could be your brakes don't like the rotors or the pads have an issue.

You mention some `chatter` but also like having a lollipop in the spokes? Have you checked your spokes?

Look forward to hearing the solution!

swod1

foo606 wrote:

There was no brake rub when the disc was installed .
Started happening 45 miles into a ride .It may be brake pad issue which I will inspect later for Glazing .But its odd that everything was peaceful before .
Lets see what a pad change does .
After that Im at a loss .May have to remove and replace with Solid Sram centerlines .

I know got a similar issue with my rear brake on a bike I have just cant get pads to bed in to the disc.

Are the sram pads organic?

foo606

Sram pads are what came with The Ultimate as Standard .I will check CRC to see what they are I usually run Noah and Theo Ceramic pads .No issues with these .Tho they take some bedding in.
I have a fairly good lever feel with good modulation .

foo606

Sram Trail pads ?

steve_sordy

I had something similar to that, except not chatter, just a noise like a car horn. It just started one day without obvious cause and I just could not get rid of it. I tried everything that I, the mtb forum I was using at the time could think of, and also the bike manufacturer's technical guru could think of. When I was descending a long hill in the Alps, everybody thought there was a runaway car coming up behind them! The bike was shaking so hard I thought it would damage all the bearings!

In the end I dismantled the bike and sold all the parts.

Years later I suspected that that it was caused by a small bit of air in the rear brake system, the air acting as a spring like it does in your forks. Rear brakes are harder to clear of air due to the long and twisting length of the hose. What I did when I had a similar fault that I had not done before was this: Clamp the brake lever full on and secure with a zip tie or very strong rubber band. Stand the bike upright so that no bubbles can get trapped anywhere in the system. Leave it overnight. This compresses any air to very tiny bubbles and allows them to rise to the lever reservoir. Bleed the reservoir. This also works to get rid of slightly spongy brakes that work OK, but that you feel could be better.

I'm not saying that this would have worked for my problem before, or for yours now. But it was the only thing I could think of that was not tried apart from throwing away the complete brake system.

lemonenema

thats an interesting one Steve (im guessing it was on MBR forum?) strange how air bubbles in oil would cause noise though.

foo606

Well all sorted .Oddly it was the pads .Not sure if it was uneven pad and caliper alignment or just glazed Pads .
Put in a new set of ceramic pads and its all quiet again .

mattyfez

Might be anecdotal but I fitted some sram level TL brakes with shimano ice tech floating rotors (at least I think that's the right term).
The rear 160mm behaves nicely but I get a weird pulsating vibration from the front 180mm disk when braking at... Dunno medium pressure, at very light pressure it's fine and if want to brake very hard it's fine.
I'm not sure if it's caliper alignment or an uneven pad. (pads are standard ones that come with level TL) .

I had to use a caliper mount adaptor for the front for the bigger disk. That might play a part but it's all tight and in line from what I can tell.

foo606

mattyfez wrote:

Might be anecdotal but I fitted some sram level TL brakes with shimano ice tech floating rotors (at least I think that's the right term).
The rear 160mm behaves nicely but I get a weird pulsating vibration from the front 180mm disk when braking at... Dunno medium pressure, at very light pressure it's fine and if want to brake very hard it's fine.
I'm not sure if it's caliper alignment or an uneven pad. (pads are standard ones that come with level TL) .

I had to use a caliper mount adaptor for the front for the bigger disk. That might play a part but it's all tight and in line from what I can tell.

Im running 203 mm on the front and rear .
I didnt like the Sram pads that came with the brakes so I swapped them for Ceramic ones .
I would check the post mount is on tight .
I have an adapter on mine and they are fine with ceramic pads .
A little honky on the rear when wet but wore off after a minute or 2 with braking .

swod1

foo606 wrote:

Well all sorted .Oddly it was the pads .Not sure if it was uneven pad and caliper alignment or just glazed Pads .
Put in a new set of ceramic pads and its all quiet again.

The sram pads must be resin organic then and you've ridden they've got hot and glazed causing the noise after a while on your ride?

Never heard of ceramic brake pads for bicycles, who manufactures these?

I'm interested in trying them on my rear brake the pads I've tried are just glazing and making a right noise. Takes me back to hassle I had with shimano resin pads if you don't bed them in right they just make noise.

Run fine uberbike race matrix on front but rear tried semi metallic, organic was even going to run sintered again.

foo606

swod1 wrote:

foo606 wrote:

Well all sorted .Oddly it was the pads .Not sure if it was uneven pad and caliper alignment or just glazed Pads .
Put in a new set of ceramic pads and its all quiet again.

The sram pads must be resin organic then and you've ridden they've got hot and glazed causing the noise after a while on your ride?

Never heard of ceramic brake pads for bicycles, who manufactures these?

I'm interested in trying them on my rear brake the pads I've tried are just glazing and making a right noise. Takes me back to hassle I had with shimano resin pads if you don't bed them in right they just make noise.

Run fine uberbike race matrix on front but rear tried semi metallic, organic was even going to run sintered again.

Noah +Theo do good ceramic pads orange backed .
Really smooth and quiet in all situations ,
£6.99 a set available on Amazon .

lemonenema

discobrakes is another