Increasing pad clearance on Ekar brakes

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NickJHP
Posts: 462
Joined: Wed Feb 14, 2018 2:22 am
Location: Canberra, Australia

by NickJHP

I like the feel of the brakes, but the pad clearance, compared the half dozen other Shimano and SRAM hydro brake setups I have on other bikes, is too minimal. The brakes engage almost immediately the lever is depressed, and the slightest amount of runout on the rotor or temporary warping after prolonged braking leads to the rotor rubbing on the pads.

Any suggestion on any way to get better pad clearance on the brakes?

rollinslow
Posts: 864
Joined: Fri Dec 21, 2018 2:25 am
Location: New York

by rollinslow

NickJHP wrote:
Thu Jul 14, 2022 1:03 am
I like the feel of the brakes, but the pad clearance, compared the half dozen other Shimano and SRAM hydro brake setups I have on other bikes, is too minimal. The brakes engage almost immediately the lever is depressed, and the slightest amount of runout on the rotor or temporary warping after prolonged braking leads to the rotor rubbing on the pads.

Any suggestion on any way to get better pad clearance on the brakes?
I would remove the pads, and "exercise" the pistons first. Basically, use a plastic tire lever to put them back in, then squeeze the lever a few times (careful not to push them all the way out). Also, rub a very tiny amout of mineral oil on the piston while you do this to lubricate the seals. Be careful because you can easily contaminate the rotors later when putting the wheels back in. Sand with coarse-grit fresh paper and re-bed is also reasonable.

If that doesn't help, try switching to the AFS 03 rotors which are very slightly thinner. I had that issue on my wife's Ekar bike, and now it is solved. I also think the Ekar rotor was not perfectly straight.
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ParisCarbon
Posts: 1918
Joined: Mon Feb 05, 2007 5:39 am
Location: Winnipeg Canada

by ParisCarbon

Reviving old thread... I bled my Ekar brakes today... what I noticed and Im not sure if this is common as Im more of a rim brake guy , and didnt look on my Venge with EPS disc..
When initially setting up, the pistons are dead flush with the inner surface of the brake which gives ample clearance either side from pad to rotor.. the minute you engage the brake though, I noticed there was a soft pull on the lever, and then they went normal, but its now offset the piston about 1/2 mm out from the inner wall of the caliper.. so that has now taken away the space between the pad and disc and making it very difficult to get any alignment... resetting the piston back in flush yields the same result... Ive tried cleaning the pistons etc, they just don't fully reseat flush on release of the lever... they feel perfectly fine... is that normal that the piston is set a little bit out, and the only way for more clearance as stated above is to use the AFS 03 rotor?

TobinHatesYou
Posts: 12456
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

ParisCarbon wrote:
Sun Apr 16, 2023 2:05 am
Reviving old thread... I bled my Ekar brakes today... what I noticed and Im not sure if this is common as Im more of a rim brake guy , and didnt look on my Venge with EPS disc..
When initially setting up, the pistons are dead flush with the inner surface of the brake which gives ample clearance either side from pad to rotor.. the minute you engage the brake though, I noticed there was a soft pull on the lever, and then they went normal, but its now offset the piston about 1/2 mm out from the inner wall of the caliper.. so that has now taken away the space between the pad and disc and making it very difficult to get any alignment... resetting the piston back in flush yields the same result... Ive tried cleaning the pistons etc, they just don't fully reseat flush on release of the lever... they feel perfectly fine... is that normal that the piston is set a little bit out, and the only way for more clearance as stated above is to use the AFS 03 rotor?

This is indeed normal behavior for disc brake calipers/pistons. They will advance to the point where they will leave only the slightest gap. The will continue to advance as both the pads and rotors wear thinner.

ParisCarbon
Posts: 1918
Joined: Mon Feb 05, 2007 5:39 am
Location: Winnipeg Canada

by ParisCarbon

TobinHatesYou wrote:
Sun Apr 16, 2023 2:38 am
ParisCarbon wrote:
Sun Apr 16, 2023 2:05 am
Reviving old thread... I bled my Ekar brakes today... what I noticed and Im not sure if this is common as Im more of a rim brake guy , and didnt look on my Venge with EPS disc..
When initially setting up, the pistons are dead flush with the inner surface of the brake which gives ample clearance either side from pad to rotor.. the minute you engage the brake though, I noticed there was a soft pull on the lever, and then they went normal, but its now offset the piston about 1/2 mm out from the inner wall of the caliper.. so that has now taken away the space between the pad and disc and making it very difficult to get any alignment... resetting the piston back in flush yields the same result... Ive tried cleaning the pistons etc, they just don't fully reseat flush on release of the lever... they feel perfectly fine... is that normal that the piston is set a little bit out, and the only way for more clearance as stated above is to use the AFS 03 rotor?

This is indeed normal behavior for disc brake calipers/pistons. They will advance to the point where they will leave only the slightest gap. The will continue to advance as both the pads and rotors wear thinner.
I do have new rotors on the wheels, but the pads are a few years old... I do have new pads, I guess putting the new pads on would help? Theres still a pile of meat left on the old pads though... Thanks!

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

by TobinHatesYou

ParisCarbon wrote:
Sun Apr 16, 2023 3:19 am

I do have new rotors on the wheels, but the pads are a few years old... I do have new pads, I guess putting the new pads on would help? Theres still a pile of meat left on the old pads though... Thanks!
Doesn't matter. If the pistons don't retract flush with the caliper, that's fine. If your brakes didn't do this, then every pull of the lever would be like that first one where there's zero feedback/resistance all the way to the bars.

de lars cuevas
Posts: 182
Joined: Fri Jul 28, 2006 8:28 pm
Location: the Netherlands

by de lars cuevas

rollinslow wrote:
Thu Jul 14, 2022 2:04 am
NickJHP wrote:
Thu Jul 14, 2022 1:03 am

Any suggestion on any way to get better pad clearance on the brakes?
try switching to the AFS 03 rotors which are very slightly thinner. I had that issue on my wife's Ekar bike, and now it is solved. I also think the Ekar rotor was not perfectly straight.
Riding Ekar myself, I agree that it has a quite small clearance between brake pads and disc.
It is a factory set result of piston diameters, lever throw, dynamic seals etc. You cannot change this.

Not even with thinner discs: since the system is self compensating for pad wear, you'll end up with the exact same clearance.

To mimimize drag, keep the piston clean, keep calipers centers, keep the discs straight... And stay out of the wet grit. 🙂

Cheers, Lars

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