SRAM Hydraulic on Shimano rotors?

Discuss light weight issues concerning road bikes & parts.
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djbowen99
Posts: 75
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

I switched over from Ultegra disc to eTap HRD and left the Shimano rotors assuming they would play well together. I'm experiencing serious grinding, pulsing and noise issues. After spending countless hours beleeding, adjusting, centering, test riding, etc i am so over this. Only other thing i can think of is swapping over to SRAM rotors but before i spend the $100 has anyone had luck with SRAM on Shimano rotors (the rotors are the newest models)?
Last edited by djbowen99 on Fri Jun 29, 2018 6:12 pm, edited 1 time in total.

jeanjacques
Posts: 124
Joined: Thu Apr 14, 2016 11:01 am
Location: France

by jeanjacques

Sram Red hydro PM with XTR RT99 rotor, no problem at all.

by Weenie


motorapido
Posts: 268
Joined: Fri Jul 30, 2010 7:08 pm

by motorapido

There are a couple of possibilities it could an issue with the pads, as you use the brakes more it will probably settle down as the new pads conform to the part worn discs, Or it may be down to the actual pad material being different, again as the brakes bed in it may settle down and this can take some time.

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hmai18
Posts: 652
Joined: Mon May 15, 2006 12:19 am
Location: Vancouver, BC, Canada.

by hmai18

Did you properly bed in the new pads?

I've run Rival1 hydro calipers with both RT-99 and RT-86 rotors for 3 seasons of cross and gravel adventures in all sorts of conditions without issue.

dvq
Posts: 127
Joined: Mon Sep 25, 2017 1:36 pm

by dvq

If you're going to use a new pad shape you probably need a new rotor, you might be hitting a high spot you haven't hit before.

djbowen99
Posts: 75
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

i believe i did bed in properly but these rotors were used with the ultegra group for a few hundred miles first.

TobinHatesYou
Posts: 1773
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

I’ve tested basically every centerlock rotor available with SRAM HRD calipers. IceTech rotors do tend to judder/pulse and make that turkey gobble sound at lower brake strength. Campy H11 rotors are the worst in terms of noise as the vent design results in a mid-frequency droning noise.

Pay the $100 fo a pair of Centerline X rotors. They have the best vent design of any rotor on the market, specifically engineered to prevent funny whistling noises.

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stockae92
Posts: 283
Joined: Fri Sep 25, 2015 5:13 pm

by stockae92

I only have experience of disc rotor in MTB, and I have no problem running switching between SRAM and Shimano rotors. But the pad has been seen both kinds of rotor since new.

djbowen99
Posts: 75
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

I think i found the issue, the pad is making contact with a recessed section of the rotor. it looks like the SRAM caliper/pads sit a tad lower. i thought i screwed up and set them for a 140 disc but they look correct.

Image

Image

TobinHatesYou
Posts: 1773
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Correct. That is one of the reasons why you get some judder/noise. The notch on the outer edge of the rotor doesn't help either. Even that long vertical vent that leads to the black alloy carrier is a source of noise because air can escape as the pads pass over it.

djbowen99
Posts: 75
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

Ordering SRAM centerlock rotors and new pads now...

The horrid pulsing is only under full braking which makes sense. I really hope new rotors are the fix.

scale29
Posts: 67
Joined: Sat Jun 04, 2011 5:40 pm

by scale29

The pad sits in that location on the Shimano caliper too, but I haven’t experienced any noise from mine. Let us know how you get on with the SRAM rotors.

djbowen99
Posts: 75
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

The Shimano pads that were on the Ultegra brakes have a beveled edge on the bottom which should be just enough to not cause the issue.

Image

djbowen99
Posts: 75
Joined: Sun Aug 16, 2015 1:46 am

by djbowen99

So far the SRAM rotors are not causing any issues but I have only done the bedding in with laps around the block. It's pretty clear when viewing them on top of each other that the the indent is likely the culprit on the Shimano rotors. I also saved a few grams which i imagine will decrease once there's some more pad on the rotor.

Image Image Image Image Image uploading pictures

TobinHatesYou
Posts: 1773
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

You are not going to gain a gram in weight from transferring pad material to the rotor.

by Weenie


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