Sram Red disc caliper vs etap HRD caliper

Discuss light weight issues concerning road bikes & parts.
spud
Posts: 804
Joined: Sat Feb 07, 2009 5:52 am

by spud

Gents,

I have some plumbed Etap post mount calipers that i'd like to change out for flat mount. I note that there is a both a Red flat mount caliper and an Etap flat mount caliper available. Are they interchangable? Do they have the same hose & hardware at the lever and caliper?

I also noted that in their install video, they say to cut the line at the lever end of the hose, rather than the caliper end. So long as you properly install the hose hardware and bleed thoroughly, I can't see the difference in cutting either end, though cutting at the caliper perhaps creates more work in bleeding, given the relatively complex geometry of the pistons/cavities etc.

TIA

spud
Posts: 804
Joined: Sat Feb 07, 2009 5:52 am

by spud

answering my own question, it looks like both calipers use a banjo fitting to connect the line to the caliper. Therefore, just move the banjo to the new caliper and bleed using SOP.

by Weenie


vanmatthew
Posts: 82
Joined: Thu Jul 14, 2016 5:20 am

by vanmatthew

Yup. I was going to say they're both basically the same.

spud
Posts: 804
Joined: Sat Feb 07, 2009 5:52 am

by spud

^thanks for your input. I checked with SRAM, they maintain that you need to use HRD calipers with Etap, rather than Red. I checked piston sizes, thinking perhaps they changed them, but no, same size in both. Have to say I don't understand their stance on this - calipers should not be black box stuff. Perhaps the bleed port is a little different? Not that it would prevent use.

MichaelB
Posts: 619
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

That's because they want you to spend more. Calipers have surprising cross-compatability.

spud
Posts: 804
Joined: Sat Feb 07, 2009 5:52 am

by spud

I chased this down a little further. Near as I can tell from the SRAM catalog, the two calipers use the same piston rebuild kit, so they should work just fine. The H spring and pads are a different part number, but so long as you can get Red pads, should not be an issue. The big difference is that the HRD is a monoblock caliper, whereas the Red is a bolt together caliper. Maybe that has a small effect in really hard braking, but in general use I suspect not.

Cattiy
Posts: 60
Joined: Mon Jul 14, 2014 6:08 pm

by Cattiy

spud wrote:
Mon Mar 04, 2019 6:27 pm
I chased this down a little further. Near as I can tell from the SRAM catalog, the two calipers use the same piston rebuild kit, so they should work just fine. The H spring and pads are a different part number, but so long as you can get Red pads, should not be an issue. The big difference is that the HRD is a monoblock caliper, whereas the Red is a bolt together caliper. Maybe that has a small effect in really hard braking, but in general use I suspect not.
Thank you very much for this information, because this is actually my situation? Did you change the callipers already?

spud
Posts: 804
Joined: Sat Feb 07, 2009 5:52 am

by spud

I haven't done the build yet, weather here has been so crappy that I'm not in a rush to get it out on the road.

mrirocz
Posts: 17
Joined: Thu Feb 08, 2018 1:48 am

by mrirocz

I am in the same situation. The normal Red caliper will not work with your ETAP shifters/Levers. You will need to buy the 'HRD' version of the caliper. I found this out the hard way.

MichaelB
Posts: 619
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

mrirocz wrote:
Mon Mar 11, 2019 1:28 am
I am in the same situation. The normal Red caliper will not work with your ETAP shifters/Levers. You will need to buy the 'HRD' version of the caliper. I found this out the hard way.
What is the issue ?

youngs_modulus
Posts: 575
Joined: Wed Sep 20, 2006 1:03 am
Location: Portland, OR USA

by youngs_modulus

Good question. I’m curious about the actual problem as well. Mrirocz, what exactly did you learn the hard way?

spud
Posts: 804
Joined: Sat Feb 07, 2009 5:52 am

by spud

looks like the syringe/bleeder fitting used at the caliper is different. Certainly not a deal breaker if you have the appropriate fitting..

mrirocz
Posts: 17
Joined: Thu Feb 08, 2018 1:48 am

by mrirocz

Hey guys, so I mistakenly ordered the SRAM ETAP Group with Post Mount calipers. I ordered the SRAM Red hydraulic calipers and took them to my mechanic for install. He was not able to do the install because he said they did not function properly. He did some research and spoke with SRAM. They said that the proper caliper should be the 'SRAM Red etap HRD" version. Apparently, the etap version shifters/hydraulic reservoir is different than the mechanical shifter reservoir and causes the brakes to not work.
I don't know the exact technical issue of why they are not working. I don't believe it is my mechanic since he has been doing this type of work for years.

mrirocz
Posts: 17
Joined: Thu Feb 08, 2018 1:48 am

by mrirocz

https://sram.zendesk.com/hc/en-us/artic ... -calipers-

Quick research on SRAM's website...they don't give specifics as to why they are not compatible. It is a bitch trying to find the etap HRD Calipers. No one seems to have anything in stock.

jlok
Posts: 1061
Joined: Tue Jun 30, 2015 3:30 am

by jlok

Litespeed T1sl Disc / BMC TM02 < Giant Propel Advanced SL Disc 1 < Propel Adv < TCR Adv SL Disc < KTM Revelator Sky < CAAD 12 Disc < Domane S Disc < Alize < CAAD 10

by Weenie


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