Gt Avalanche 1.0 noise driving me mad help please ....

rogcovy
rogcovy Posts: 10
edited February 2011 in MTB workshop & tech
Hi All.

My problem is ... my 5 year old Avalanche has been making a realy bad noise even my lbs has had troble finding it , the noise comes on mainly when i go off road peadling realy hard and when i go through dirt and water seems to make it worse but i have also had the noise when bike is clean and all lubed with clean oil. It sounds like a brr bbr brrr that is quite quick noise under load and i can feel it through the frame and pedals but not when free wheeling it sounds like the jocky wheel is hitting the cassett but its not that ... have checket that a load of times, it seems to be worse in the bigger cogs of the cassett but can happen in all of them , front chain ring position does not make a difference, so far i have had replaced .... the cassett , chain , front chain rings , bottom bracket , free wheel hub, wheel bearings , all have made no difference . have tried diffrent pedals removing the front Derailleur in case the chain was hitting that no change , i can ride to work all week on the road and not get noise then it come back again, even cleaned all the spole intersections and lubed spoke nipples , no joy , lbs wants to replace rear mec but have no probs with gear change even when noise is there . Any help would be much appreciated.

Many Thanks

Roger

Comments

  • supersonic
    supersonic Posts: 82,708
    Is a process of elimantion I am afraid.

    Try Park Tools website: they have a great guide on diagnosing noises.

    I'd guess the chain may be rubbing the front mech, caused by flex in the chainset.
  • rogcovy
    rogcovy Posts: 10
    Hi . thanks for reply , have been through park tools site but still no help , as for front mech , i have removed that compleatly and noise still there :evil:

    Rog
  • ftwizard
    ftwizard Posts: 253
    Do you have a picture of the rear mech?
  • rogcovy
    rogcovy Posts: 10
    Hi , I can get picture up over the weekend, its a Deore LX long cage it thet helps

    Rog
  • Buckled_Rims
    Buckled_Rims Posts: 1,648
    I'd be very tempted to take everything off the bike for a full clean and inspection. It's pointless buying new stuff if you have no idea where it's coming from.
    CAAD9
    Kona Jake the Snake
    Merlin Malt 4
  • rogcovy
    rogcovy Posts: 10
    Hi , Yep tried that took it all off even stripped the rear mech compleatly and reassembled everything with grease on all the threads and all mating surfaces including chain ring bolts and bottom bracket hollow tec 2 one

    Rog
  • Buckled_Rims
    Buckled_Rims Posts: 1,648
    In that case, as Sherlock Holmes would say, when you have eliminated the impossible, whatever remains, however improbable, must be the truth?

    The frame has a hairline crack in it!

    Of course I may be wrong :roll:
    CAAD9
    Kona Jake the Snake
    Merlin Malt 4
  • Hi Again.

    Nice new rear mech fitted 3 days ago and no noise gear change is realy good but....... took bike off road today first few big bumps and back comes the dam noise , any ideas !!!! what about back wheel spoke creak when under load or when they flex as hub and sproket drives thhe wheel forward the rims are wtbs and it has a shimino hub maybe, cant see any cracks anywhere any more ideas lads ...

    Roger
  • Jack 123
    Jack 123 Posts: 118
    my cassette was creaking and I had to get a new one, my headset was creaking at one time, my fork was creaking at one time, my cables were creaking one time. lol So many things can make noise its hard to say when I cant hear it but I know what you are saying the noise will drive you mad. Thats how I learned how to work on my bike because of the noises. Nothing worse than creak creak creak when you are riding.
  • Anonymous
    Anonymous Posts: 79,667
    If it gets worse going through water and dirt it sounds like grit getting onto the brake discs and/or the cassette & rear mech. Result is a gritty grinding sound.

    My Juicy brakes do this all the time if I ride through mud. It's not really much harm though, except may wear down the pads a bit more. Use kevlar or sintered pads and should be okay. It'll destroy organic though within a ride or two.

    If it's grit in the cassette, mech or chain then maybe consider wet lube for such rides. It's designed to keep the mud and grit out, but you want dry lube for most conditions except really muddy rides. Wet lube can cause chain suck for some people. Use sparingly.

    I find especially that my jockey wheels can make grinding noises a lot. Cleaning helps ;). Difficult to avoid mid-ride though. I'm not too fussed. Just watch the condition of the wheels though as they'll wear if grinding away like that.

    Oh, and another noise that bugged me for ages was the spring clips on the Juicy brake pads. Go over a bump and the clips shift slightly and catch against the disc. Eventually got my pad replacement and wheel fitting technique sorted so that it happens less frequently, and just live with it when it does happen.