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  1. #1
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    Force HydroR Discs Caliper Spacer Confusion

    SO I swapped out an old set of TRP Spyres on my 2015 Giant TCX for a new set of Sram Force Hydro discs.

    I'm super happy to have them on, they feel great at the lever, but I admit I haven't gotten to ride them yet.

    One thing that keeps throwing me off though is that the front caliper spacing (in particular) looks...... weird. It just looks somehow too far out to me, and I noticed that when I look at down through the caliper from above there is quite a bit of space between the top of the disc and the top of the 'cavity' within the caliper.....moreso than I'm used to seeing on other brakes. It almost looks like the pads are only contacting 1/2 of the braking surface of the 160 disc.

    I looked at the spacers my mechanic used, a 17.5mm and a 12.5mm, and see that this is the appropriate setup for a CPS Caliper and a 160mm disc on 140mm post mounts. ...it appears that IF my calipers were 'standard' calipers I would only need a 12.5 and a 7.5mm spacer. I just don't know how to tell whether my caliper is CPS or standard to tell whether the mechanic may have made a mistake or not. I looked at the picture on the sram caliper installation .pdf, but the differences between the two caliper types seem too minute for my eyes.

    Anyone know how I can check my caliper type and ensure that my spacer arrangement is correct?Force HydroR Discs Caliper Spacer Confusion-img_5918.jpgForce HydroR Discs Caliper Spacer Confusion-img_5919.jpgForce HydroR Discs Caliper Spacer Confusion-img_5920.jpgForce HydroR Discs Caliper Spacer Confusion-img_5921.jpg

  2. #2
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    The piston appears to be in the right place for those CenterLine rotors.

    Any closer and it appears the rotor would hit the caliper body.

    I have never been a fan of the CPS Avid set up. I believe it was a major contributing factor to the dredded "Turkey gobble" many Avid disk brakes users have been plaqued with for yrs.

    Here's a link to SRAMs fun about CPS, Std and Smurf mount calipers

    http://cdn.sram.com/cdn/farfuture/up...r_mounting.pdf

    Here's a snippy from it.
    Force HydroR Discs Caliper Spacer Confusion-cps.jpg
    Last edited by ziscwg; 12-10-2015 at 10:12 AM.
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  3. #3
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    Just wanted to top this up... Brought the bike back to my mechanic and he now agrees with me that something is amiss with the caliper spacing... the pads definitely only contact about 1/2 of the actual braking surface of the caliper. He also agrees that there is clearly more space in the caliper body for it to be closer to the rotor. The interesting thing is that he followed the guidelines of the chart you've copied above, which is the same chart that I reference in my original post. If the caliper is a CPS caliper then I think it *should* be right....but I'm really starting to wonder if its possibly a 'standard' caliper and if I just need to remove the CPS spacers that came with it.... TBD...I'm away on vacation now, and when my mechanic tried to call Sram for guidance he ended up waiting on hold for a 1/2 hour until he got disconnected...

    I'll let you know how it shakes out!

  4. #4
    coaster
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    Looking at the photo of your caliper and the illustration I'd say it's obvious you have a non-CPS caliper. Look at the mount compared to the bleed screw. It looks like you have a fork made for 140mm rotors but are running a 160. So, get the adapter that goes from 140 post mount to 160 and mount the caliper with no washers. The adapter you have only works with CPS washers. If you had a 160 rotor with your Spyres use that adapter. I've seen some weird caliper/rotor/adapter combos and the best advice is to let common sense and what you see dictate the setup, not confusing and sometimes contradictory instructions. If the top of the rotor touches the caliper it's too close. If not all the pad is hitting the braking surface it's too far.

  5. #5
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    It may be a dumb suggestion, but are you sure you have your spacers in the correct relative positions top to bottom (switch positions)?

  6. #6
    coaster
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    Quote Originally Posted by shinewheel View Post
    It may be a dumb suggestion, but are you sure you have your spacers in the correct relative positions top to bottom (switch positions)?
    The spacers that matter, the ones below the caliper, can't be put in a different position because the concave part is incorporated into the 160mm adapter.

  7. #7
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    Just googling around. Seems to be a lack of info on this. fwiw, the caliper is non cps, upper spacer should be 12.5 mm and lower 7.5 mm. The spacers pictured are 5 mm too long. Bolts should be 39.5 mm and 34 mm.

    https://www.sram.com/sites/default/f...ns_rev_c_0.pdf

  8. #8
    'brifter' is a lame word.
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    Quote Originally Posted by carlosflanders View Post
    Just googling around. Seems to be a lack of info on this. fwiw, the caliper is non cps, upper spacer should be 12.5 mm and lower 7.5 mm. The spacers pictured are 5 mm too long. Bolts should be 39.5 mm and 34 mm.

    https://www.sram.com/sites/default/f...ns_rev_c_0.pdf
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  9. #9
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    You don't say.

    Don't you have better things to do than pointing out the ridiculously obvious?

  10. #10
    'brifter' is a lame word.
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    Quote Originally Posted by carlosflanders View Post
    You don't say.

    Don't you have better things to do than pointing out the ridiculously obvious?
    That seems ridiculously obvious, doesn't it?
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  11. #11
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    Yes, it does.

    This thread is the first thing that comes up on the topic in a google search. It also has some useful pics. I spent some time yesterday figuring out the same problem. Made sense to add to the thread rather than start a new one. Might save someone some time in the future.

  12. #12
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    and soon, I predict there will be a "Brake Time" sub-forum like on Mtbr. Watch!

  13. #13
    'brifter' is a lame word.
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    Quote Originally Posted by aclinjury View Post
    and soon, I predict there will be a "Brake Time" sub-forum like on Mtbr. Watch!
    Cool, another section that will get ignored.
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