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  1. #1
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    Intro and KM rear disc caliper mount question

    Howdy folks,

    I've been a forum member for quite a while, lurking and learning quite a bit, but I don't think I've ever posted. I've been riding a Karate Monkey all over Western North Carolina, Colorado, and Utah since 2006. It started out set up with a triple, but spent the majority of its life split between a SS and 1x9 setups. Love the bike and its adaptability really suits me. I've built up several other Surlys (LHTs, CrossChecks, etc) for various friends over the years, and, in general, just really love Surly for much of the same reasons I love Rivendell. This forum has been a super resource for me over the years, so thanks! I hope to start pitching in my 2 cents from time to time.

    Anyway, my KM recently lost a quick and dirty fight with my neighbor's carport in our shared driveway. I just picked up a new KM from my LBS and began swapping all the parts over. I noticed the rear disc caliper mount has changed (in 2011, I think), and everything doesn't quite fit anymore. I am using Shimano XTR hydraulic calipers (BR-M965-R) with 160mm rotors. The brakes are older and are IS mount (not post mount). I mounted the calipers on the new frame, but when I slide the wheel into the rear dropouts the rotor bottoms out in the caliper. I'm admittedly not super familiar with the disc brake world, having only ever installed and service these brakes and some BB7s. I'm stumped. Any suggestions?

  2. #2
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    The new frame is slotted for adjustment. Are you utilizing this to mitigate the issue? Also, are you using the correct adapter?

  3. #3
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    I've used the slots, but they do not over as much room as slots on my old KM. I am not using any adapter. Most of the adapters I've come by are for IS mount to Post mount or vice versa. As far as I know, the KM is designed with 51mm I.S. disc mounts (and 160 mm rotors) and these brakes are I.S. calipers.

    The old mounts look like this: http://farm4.static.flickr.com/3405/...7f7af87d22.jpg

    The new mounts look like this: http://surlybikes.com/uploads/bikes/fm_km_05.jpg

    Any suggestions on an adapter?

  4. #4
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    Sorry, nothing to add, but I thought the new frames were supposed to be much more user friendly. I've got v-brakes on mine (keeping it old school), but older frames like the one I've got (2008) had issues with caliper clearance. Surprised to hear that on the new frames.

    Can you post a picture of what you're talking about? I see the link with the brake mounts. Do you have a picture with the caliper on?

  5. #5
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    Here is a pic showing the attached caliper and one from above showing the rotor "bottoming out" in the caliper when the wheel is inserted into the dropouts.

    http://www.flickr.com/photos/jayburkhalter/9498188222/

    http://www.flickr.com/photos/jayburkhalter/9495387905

  6. #6
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    Need a login to see it photos. Oh well.

  7. #7
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    sorry about that. the links should work now.

    IMG_1431 | Flickr - Photo Sharing!

    IMG_1429 | Flickr - Photo Sharing!

  8. #8
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    Oh wow. Never seen calipers like that. I'm used to the post mount with adapters. You may very well have a problem.

  9. #9
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    Did you ever figure this out? What happens if you just slide the caliper all the way forward?

  10. #10
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    There really is not a lot of wiggle room in the new caliper mounts compared to the mount on the older Karate Monkeys. With the wheel pushed all the way forward in the dropouts, the rotor contacted the caliper. I moved the wheel back towards the middle of the dropouts (about where monkey nuts would place the wheel), and I was able to make things work.

  11. #11
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    burkhrj,

    Are you referring to the pad contact as bottoming out or the rotor running into the caliper as bottoming out?

    For that brake caliper to be centered over the rotor you have to use Shimano's shims for setup (or home setup of some sort, super thin washers, etc). There is a kit on Amazon.com referred to as "Shimano XTR BR-M975/965 Disc Brake Caliper Fixing Bolt Unit". That looks like something you need for one of your problems. In you picture from the top of the caliper it looks like there is just a tiny touch of space between rotor and caliper viewing full size. Fore/aft adjustment may help that and be noticeable ounce the shims are centering your caliper over the rotor. That's all the info I've got after doing a little bit of internet searching on how to set those brakes up.

    Hopefully you've already found a solution or this will help.

    Edit: Doh, I was typing while you already responded.

  12. #12
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    FYI I had the same problem with XT brakes at 180mm, I simply slid a pair of stainless washers in between the caliper and the adapter. I demand the shortest chainstay length available!

  13. #13
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    Quote Originally Posted by ScaryJerry View Post
    FYI I had the same problem with XT brakes at 180mm, I simply slid a pair of stainless washers in between the caliper and the adapter. I demand the shortest chainstay length available!
    Have you seen the photos? His brakes don't use an adapter.

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