Disc brake caliper catching spokes on new wheel

timbooth
timbooth Posts: 160
edited October 2007 in MTB workshop & tech
I have just replaced the wheels on my bike and the front brake caliper is catching on the spokes (only those with the shoulder facing out).

The new hub is a Deore XT, the brake is a Giant MPH (2 or 3? Not sure) and the fork is an RST specific to the bike.

I have removed all of the spacers from the inside of the brake mount and it still catches.

Do I need a new brake (the MPH caliper is really chunky)?
If so, can I run a different caliper with the current disc and lever?

Please help!!

Thanks

Comments

  • whyamihere
    whyamihere Posts: 7,715
    New brake time unfortunately. The only caliper that *might* work with an MPH lever is a Hope C2, but they've been out of production for many years. Easier to just get a new, better brake. Shimanos are excellent, you can pick up a new LX disc for around £50-£60.
  • nicklouse
    nicklouse Posts: 50,675
    or a +20mm adaptor and a bigger disc.

    depends on what size you have now.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • timbooth
    timbooth Posts: 160
    Hi, thanks to you both.

    There isn't any adapter already - the front and rear calipers look alike and without being able to measure them right now, the front and rear discs are probably 160mm???

    Would this work??

    http://www.wiggle.co.uk/ProductDetail.a ... c%20System

    I don't know what compatibility issues there are with the actual discs themselves?

    Strange that I was a bike mechanic for a number of years and can strip a bike in 15 minutes, yet I haven't a clue about hydraulic discs or suspension!!

    Thanks for your help.
  • whyamihere
    whyamihere Posts: 7,715
    That will work yes. The actual discs will be fine as well as they're universal. Your brakes will most likely be 165mm,
  • timbooth
    timbooth Posts: 160
    Right, last question then!!

    180mm or 203mm?
  • whyamihere
    whyamihere Posts: 7,715
    180 on an RST. I'd prefer to change the whole brake to be honest, as big rotors can cause problems with cheap or light forks. Definitely don't go 200mm.
  • timbooth
    timbooth Posts: 160
    Hi,

    Why not 200mm? The fork was specially-made for Giant, as it has rack-mounts on the crown (the bike is a full-susp tourer).

    Are you saying that the disc might catch the inside of the fork leg?

    Thanks (again)
  • whyamihere
    whyamihere Posts: 7,715
    No. The extra leverage on the bottom of the fork can cause the fork's bushings to wear out prematurely, meaning you'll have play between the stanchions and sliders before long. In extreme cases, very large rotors can cause cheaper/lighter and hence weaker forks to snap.
  • timbooth
    timbooth Posts: 160
    ah, got you now. Thanks. I will avoid the 203mm version.

    I thought about a whole new brake, but the bike is for touring and only cost a couple of hundred quid (second-hand). I don't want to throw loads of money at it and it isn't going to have a hardcore life.

    Thanks for all of your advice!!
  • diver-boy
    diver-boy Posts: 47
    or you could just get the wheel dished properly so that they dont touch anymore. i.e move the rim slightly away from that side of the hub! cheaper 2, lbs should do it for about 20 quid
  • timbooth
    timbooth Posts: 160
    Hi,

    Thanks for the input but the wheel is already dished properly - ie it sits squarely between the fork legs/hub flanges/etc.

    What you suggest would put the wheel off to one side, affecting the handling of the bike!!!

    The reason that the (brand-new, expert-built) XT wheels don't fit is that the flanges sit further apart than on the old Giant hub (which was probably designed to work with this old style of brake). The caliper itself is very chunky, now I look at it.

    Thanks

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