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Crossmax SL bearing help/awful rumbling sounds HELP!!!

dan2211dan2211 Posts: 10
edited March 2009 in MTB workshop & tech
Hi all, please bear with this post as i'm tryin to brain storm a little......

i got some SL's off ebay, my first look at them and i thought the rear bearing was dry.... took it to bike shop who, after visual inspection said they were ok. When riding, after a little while at speed i get a nasty grumbling, vibrating, noise and sensation throuh the bike. i obviously stop/slow down and it goes. then it will come back.....
my 1st thought was pads catching as the rotor, the rotor was hot and i guess heat expansion would cause the 2to catch more often, i also did have a little grove in one pad .... New pads arrived today and they are now on. but now i'm not sure if that was causing the noise/vibration sensation purely beacuse i'd think the heat of the rotor/expansion would cause braking, but it doesnt, the wheel spins like when cold.
Back to the bearing, if the bearing is dry, and heat is gettin to it, or centuralfual (spellin)force is knocking the grease out would that cause these effects??
I have spare bearing for the wheel - but for the life of me i cant figure out how to extract them from the hub. Does the cassette need to come off? it is a easy job on my old old deemax wheels. Do i need any special tools? can anyone list (in simple terms!) how to access the bearings.... I'm no tech head - do i need any 'specialist' tools?

cheers
dan

Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    when does this noise happen?

    when pedalling or when free-wheeling or at all times?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • the vibraton aspect when the bike feels like its gonna blow up is when riding pedling/freeriding when at speed after 10mins or so. but there is a distinct knock when spinning the wheel on the bike - i've done this with caliper on and off and noise is still there - seems to be on a certain point of rotation too. I've looked all over and wheel/tyre isnt catching frame at all and it seems to be cassette side.... i would put my ear to it but dont fancy losing part of it to the teeth!
  • stumpyjonstumpyjon Posts: 4,069
    If it was me I'd strip everything down (cassette, freehub as far as possible and hub bearings), clean regrease and reassemble. Sometimes you're better off expecting the job to take hours rather than just trying to troubleshoot. It could be something not tight enough or incorrectly aligned etc. It'll probably cure when it's rebuilt or hopefull by handling and cleaning every part it will become apparent what's bent or bust.

    Also check all the caliper bolts etc. are tight (my rear caliper came loose a couple of weeks ago, hadn't torqued the bolts properly :oops: , the symptoms were somewhat similar to what you've described).
    It's easier to ask for forgiveness than for permission.

    I've bought a new bike....ouch - result
    Can I buy a new bike?...No - no result
  • ok, after an hour or so stripping down the wheel (using mavic website) i found that the bearing in the freehub assembly is the fault..... i think! need to get a new assembly, £35or so to comfirm. all other bearings are fine - on compaison with the deemax freehub bearing this one is very rough. hope it does the trick!
  • Where on the mavic site did you find the instructions for stripping the wheels? been on the general mavic site and couldn't find much tech help etc. Anyone post a link to it, could do with knowing how to service crosstrail freehub
    cheers
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