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  1. #1
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    Post Mount or I.S. Mount?

    Regarding the caliper mount of disc brakes (Maverick SC32 front, Castellano Silk Ti rear) it has been recommended to me by a very reliable source that I should choose the post mount option, if available, on whatever disc brake of my choice. The reasons cited are greater control over alignment and improved rigidity? How do you all feel about the post-mount option in general and with regard to those two points mentioned? Thanks!
    Last edited by wyatt; 04-20-2006 at 08:38 PM.
    WYATT

  2. #2
    Meh.
    Reputation: XSL_WiLL's Avatar
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    If you're talking about the disc brake caliper, I'd so go for the post mount version of the caliper. You can always bolt on different adapters to make it IS or Boxxer mount. With IS, if you have to attach it to a post mount fork, you'll have to get an adapter and a larger rotor. The nice thing about IS is you only have to set up the caliper once. Shim it out, and torque it down. Some people have problems with post mount calipers slipping, but it's not really an issue: don't tighten the 2 bolts down all the way, grab the brake lever to center it, and then torque both bolts evenly.

  3. #3
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    [QUOTE=XSL_WiLL]If you're talking about the disc brake caliper, I'd so go for the post mount version of the caliper....

    I do mean the caliper mount, either I.S. or post-mount. The over-simplified question is "which is better with regard to horizontal alignment adjustment"? As I understand the two, I.S. bolts directly to the face of the fork or frame mount, where post mount uses an adaptor. I could be mixing them up, I often do ge mixed up in this arena. What is Boxxer mount? Sounds like a Shimano product for the Boxxer fork. I am going to use Formula K24 brakes with a King rear and Maverick front hub on an SC32 fork.
    WYATT

  4. #4
    Nouveau Retrogrouch SuperModerator
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    Post mount and specifically Avid's CPS/TriAlign mounting setup.
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  5. #5
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    Quote Originally Posted by shiggy
    Post mount and specifically Avid's CPS/TriAlign mounting setup.

    Thanks. Now I am looking at a BTI bike catalogue and correct me if I am wrong, but it appears that applies only to AVID brakes. Thus are you are suggesting AVID brakes to obtain the mounting flexibility I asked about or does this work with other post mount calipers?
    WYATT

  6. #6
    Meh.
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    CPS is only for avid brakes... Unless you want to start hacking away at your adapters. And I know it's been done. But CPS is great, it can compensate for small imperfections in the mounting surface, almost completely eliminating the need to face the frame/fork tabs.

  7. #7
    I already rode that
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    If weight is a concern and you arent going bigger then 160mm then IS is better like someone said you just shim and bolt it on as most IS calipers are set to 160mm.
    Riding F/S since oct 94'

  8. #8
    Singletrack Addict!!!
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    Another vote for post mount in calipers and forks. Greater flexibility.
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  9. #9
    pronounced may-duh
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    In my experience, the post mount is easier to set up because there are no shims to play with. The downside of the post mount is that it can shift out of alignment. Once set up the IS mount will stay in position better.

  10. #10
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    A Dirt Rag article indicates that the industry may indeed be changing to post mount for great flexibility. This is also what I was told by a higly respected manufacturer. But post mount going out of alignment sounds unfortunate. Could thread-lock apply here?

    I know you all could be sick of hearing me, but going out of alignment which you can correct beats shaving metal off the mounts to fit an I.S. that won't align (in the direction opposite of shimming- too far out). Shims are fine for the other direction. Of course new pads and readjustment could take care of everything and my whining. That is, for this bike. I can't have anybody re-facing my frames. Shaving is the correct term because it comes faced by Ventana, in the case of my current bike, and by Steve Potts, in the case of the bike to come, a Silk Ti. There's no question it's faced properly. So then if an I.S. a less-experienced guy than the frame-builder in a local shop has to be enlisted to shave it down? No.

    Does anyone know if Formula K24 brakes are adjustable in any way like the Juicys are?
    Thanks, all.
    WYATT

  11. #11
    bang
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    i think you're making the whole IS thing a bigger deal than it really is. if you go with an IS caliper, you will probably just have to add shims (you might not have to add any). the fork may or may not need to be faced. as for post-mount, if it ever does shift out of place it takes a whole 30 seconds to readjust, if that. post-mount is more versatile, but if your fork and frame are IS, then go IS and save some weight. otherwise go post-mount.

  12. #12
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    Just wish the industry would standardize on one standard!

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