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  1. #1
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    Outcast 29 rear brake mounting???

    Just curious if perhaps it is just me or if anyone else had an issue with mounting their rear disc brake on their outcast?

    I have mind set up as an SS and have run both Hayes Stroker Carbon brakes as well as BB7's. In both cases, they were post mounts so an adapter was needed. When I installed the adapter, the caliper would rub on the rotor. I ended up filing down the adapter where the screws enter it from the drop out plate (where it attaches to the bike if you will). This pretty much solved my problem.

    This weekend however, I scored a set of Marta brakes from a friend of mine. They are IS mount so I pulled the rear adapter/brake off and when to put the new one on. I was hit with the same situation. The caliper was rubbing on the rotor. I did not even have pads in the calipers at the time as I was just test fitting things.

    I have White Industries hubs and the only thing I can think that would allow me to mount the rear one would be adding a somewhat thin washer on the axle to provide a little more space. Not sure how tricky that would make installing the wheel however.

    On the front end, I noticed that since it is a IS mount style brake, my fork is post style, I will need an adapter there. However, when trying to hold the caliper up to the post mount, I am thinking that I will be in the same situation on the front. Basically when the caliper is sitting on the rotor, the caliper mounts line up right in the middle of the post mounts. Not sure how an adapter would allow this to line up properly.

    So, my Marta's are now sitting in a drawer unable to be used and I am still running my BB7's. Not that there is anything wrong with them mind you. They work quite well but hydraulics are just so much smoother and require alot less squeezing to get the same power out of them.

  2. #2
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    I would imagine shimming would be the normal way to center calipers. I say this having not changed IS mounts, though.

    Here's a link to a place which has all sorts of brake adapters. I noticed they mention IS, too.

    Disk Brake Adapters : North Shore Billet

  3. #3
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    Shimming the rear wheel is possible though as mentioned, could make installing the rear wheel a bit of a pita on a regular basis.

    Thanks for the link.

  4. #4
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    I should have been more specific. I would think shimming the caliper would be the route.

  5. #5
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    Just checked them out. From what I can see, they don't make a post mount to IS adapter. They all seem to go from IS to post and the post mount ones they sell simply allow you to run larger rotors on a post mount set up. Basically, post to post if you will.

  6. #6
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    I guess I should have been more clear myself. Shimming the caliper would be easy. However, the caliper is hitting the rotor on the outside edge. Basically it is squeezed between the caliper mount and the rotor. Adding a shim would cause it to rub more or not fit at all. I basically need to move the rotor away from the caliper if you will or move the caliper out away from the rotor (toards the left if standing behind the bike).

  7. #7
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    Sounds like a posting in the brake section is in order. Maybe someone there has run into this.

  8. #8
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    Yep, that will probably be the next stop. I doubt I will keep the Marta's though. As nice as they are, I just can't see how I would make the front work. The reality is that I really just need a post mount set and all problems would be solved.

  9. #9
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    1SPD, it must be a wheel/hub or rotor issue, because my outcast(the same one as yours) has juicys that mounted with no problem. Is there perhaps a thin washer that can be moved from the drive side of the hub to the non-drive side? That would be ideal, as there would be no net increase in hub width. Another possibility is if you use spider-style rotors, they may have a thickness that bumps the rotor outwards a fraction- in which case a non-spider style rotor would fix the issue. FWIW I am using a WTB SS rear hub, with G6 rotors. Good luck!
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  10. #10
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    Nope, no washers to speak of. Below is a picture (first picture) of my hub back when it was in a 26" wheel. Granted it is of the drive side but the non drive looks the same. No washers. The rotors are different than what is pictured (now have KCNC rotors). They are flat against the mounting flange.

    In the second photo (moto as it sits now) you can see where I had to grind down the brake adapter in three different places. The first and most obvious point is near the slider area. The weld on my frame was sort of goopy here and would not allow the mounting plate to sit flush. I ended grinding on the adapter as opposed to the frame. I assure you it sits flush now (hard to see from the picture). The other two areas are where the (ti bolts) connect the adapter to the slider. I basically ground down the two small flanges that stuck out on the adapter thus giving me about 2mm more space. I have now used this adapter on this frame with two different sets of brakes w/ post mounts with no problems. But mounting an IS style right to the slider just doesn't yield enough clearance and the rotor makes contact with the caliper edge closest to what you are looking at.
    Attached Thumbnails Attached Thumbnails Outcast 29 rear brake mounting???-rear%2520wheel.jpg  

    Outcast 29 rear brake mounting???-brake-bolts.jpg  


  11. #11
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    I guess then the most elegant solution is to get some avid elixir or xx($$$$). Another work-around would be to mill a mm or so off the inside of the contsct points of the slider-know any machinists? Some judicious, precision filing would probably suffice in a pinch. But I suspect you knew that already...
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  12. #12
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    If I read this correctly, the caliper is too close to the center of the bike? If so, machine an appropriate amount from the I.S. to P.M. adapter to move the caliper outwards. Good luck.

  13. #13
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    I thought about ordering another slider plate from BikeIsland and then sending it to HBC (home brewed components) to have him mill it down for me. I actually have a machine shop here on the campus where I work but no longer have a contact over there that could potentially mill it for me. On the flip side, that would really only take care of the rear. I still have a post mount fork and the IS caliper simply won't work there. For now, I am just going to sit on the brakes as I will probably have a new frame by spring anyway. I will then revist the whole brake issue at that point.

    As for Avid's well, they aren't even on my list. I have had too many friends suffer problems with them to the point that the only Avids I will ride are the BB7! Yep, tried and true, highly adjustable on the fly, best bang for the buck brake on the market imo. But hydralics still feel so much smoother.

  14. #14
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    Quote Originally Posted by AZ.MTNS View Post
    If I read this correctly, the caliper is too close to the center of the bike? If so, machine an appropriate amount from the I.S. to P.M. adapter to move the caliper outwards. Good luck.
    If you look at the picture above, the slider plate is IS and so is the brake (Marta brake not pictured but it is also IS). I would have to mill down the slider plate or the brake itself.

    Honestly, when my buddy and I were working the deal, neither of us thought much about the brake mount style. I can just as easily return the brakes to my buddy as he realizes that we both dropped the ball on that one.

  15. #15
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    With the front you have elongated mounting holes in the caliper body, no? I would imagine that would give you enough fiddle room to make it line up?

  16. #16
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    When you say front, I am assuming you mean front wheel/brake. To answer the question, no, there are no slots if you will in the caliper body. Both front and rear Marta brakes are IS mounts. They simply have threaded holes that the mounting bolts go thru. My fork is a White Brother Rock Solid w/ post mounts. The bottom line is that there is no adapter to go from post mount to IS (just the other way around-from what I can find).

    Here's a picture of my fork/hub/brake so you can see the post mount set up.
    Attached Thumbnails Attached Thumbnails Outcast 29 rear brake mounting???-frt.-brake.jpg  


  17. #17
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    When I looked at other Magura IS brakes I seem to recall the holes being elongated. I guess the Marta's aren't.

  18. #18
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    I believe they are elongated on the post mount style which allows you to slide them back and forth on the post mount to get them centered. But the IS versions are threaded and the only way you can adjust them for centering is by adding small washer (which I have on hand). However, I need more space and not washers in my case.

  19. #19
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    I looked up what I was talking about. This is a front IS, with elongated holes, right? Maybe it was a later feature?


  20. #20
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    That is a post mount caliper. It is the exact style as to what I have posted above (of my BB7's) an IS mount looks like this:
    Attached Images Attached Images  

  21. #21
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    sorry for the delay, kept having file format problems. You can see that the mounting holes are from the side on the IS style verses vertically on the PM style.

  22. #22
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    Maybe I have them backwards? Anywho I've run out of time. Will be back laters.

  23. #23
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    Perhaps that is the case.

    Since there are pictures on here, I will explain:

    1. The picture of my fork shows a post mounted caliper mounted directly to a post mount.
    2. The picture of the rear brake shows a post mounted caliper mounted to an IS mount via the use of an adapter. That being said, my frame technically has an IS caliper mount on the rear, so the Marta IS caliper should simply bolt right to it. Which, technically it does. The only problem is that it rubs on the caliper hits the rotor. Its as if the slider plate is too think.

  24. #24
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    Quote Originally Posted by 1SPD View Post
    I thought about ordering another slider plate from BikeIsland and then sending it to HBC (home brewed components) to have him mill it down for me. I actually have a machine shop here on the campus where I work but no longer have a contact over there that could potentially mill it for me. On the flip side, that would really only take care of the rear. I still have a post mount fork and the IS caliper simply won't work there. For now, I am just going to sit on the brakes as I will probably have a new frame by spring anyway. I will then revist the whole brake issue at that point.

    As for Avid's well, they aren't even on my list. I have had too many friends suffer problems with them to the point that the only Avids I will ride are the BB7! Yep, tried and true, highly adjustable on the fly, best bang for the buck brake on the market imo. But hydralics still feel so much smoother.
    That's too bad, and I hope your system ends up working for you. As far as avids, I have only had good results from their hydros, performancewise. As a former wrench, I worked with Hayes, Magurs, Shimano, Formula, and Avid, including installing, bleeding, and adjusting. Tha avids were much easier to work with on all accounts IME. But to each their own, obviously.

    Cheers
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