Results 1 to 8 of 8
  1. #1
    mtbr member
    Reputation:
    Join Date
    Aug 2008
    Posts
    170

    ??Why does rear hub disengage when temp. is <32 degrees

    I have an '06 Avalanche GT with a shimano FHM475mm rear hub on it. I do some adventure racing with it and twice now after riding through creeks and rivers with the temp. below 32 degrees the rear hub has failed to disengage and therefore I can peddle but the hub free wheels. It never hooks up. I haven't taken the hub apart because I don't have the tools, but I'm wandering if anyone knows what the cause might be. I have other teammates that do the same thing and nothing happens with their hubs. I have already had GT replace the rear wheel and it has happened again already.

    I suspect that somehow moisture is getting in there and when freezing it disables the pawls or whatever is in the hub from hooking up. If that is correct how do I fix this and or is there a better hub that I can get which won't do this?

    Thanks in advance for your help,

    E

  2. #2
    mtbr member
    Reputation: gm1230126's Avatar
    Join Date
    Nov 2005
    Posts
    2,939
    It's got to be freezing open to allow it to freewheel. It's a Deore series hub so made in Malaysia. Have you had it apart to see if it needs to be cleaned or lubed? Try flushing it with Trilow or something similar and see if that helps. Could be a combination of cold water getting in and stiffening up what grease or lube is in the freehub body also also. Will it reengage after a while or does it stay stuck open until you warm it up?
    Needed: 26.8mm XTR seatpost, blue GT/Grundig Jersey.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Aug 2008
    Posts
    170
    I have not had it apart to look at it. I might need to buy some tools to do that. The LBS said it is hard to take it apart so I never have. This is a new hub-2 months old and I haven't had it in the mud or rain that much until last weekend where it just got wet. Yesterday morning is when it locked out and would free wheel. I through it in the minivan and warmed it up. Once I did that everything worked until the 20 degree temp. cooled it down to freezing again. It locked out and would free wheel again.

    I don't know what kind of grease might be in there but I'll at least try to get some grease with a low temp. threshold. Would this same sit. happen on a better quality hub? I don't know how much better the internal components are on a Chris King 500 dollar hub verses this Shimano.

    All feedback is appreciated.

    E

  4. #4
    mtbr member
    Reputation:
    Join Date
    Nov 2004
    Posts
    954
    I've never had that problem with my crossmax wheels. My Force has shimano lx hubs so I'll find out this winter if it's a shimano thing or not. I guess a better lube like you said may help you out. Better seals too.

  5. #5
    mtbr member
    Reputation: Dogboy's Avatar
    Join Date
    Jan 2004
    Posts
    1,132
    The grease in the freehub body is too heavy and it that is keeping the pawls from engaging when it is cold. You could flush the freehub body with a thinner grease using a Freehub Buddy - http://www.morningstartools.com/freehub_buddy1.html
    This should allow the pawls to engage in the cold weather. I would flush it with slightly thicker grease when the temperature warms back up.

  6. #6
    local trails rider
    Reputation: perttime's Avatar
    Join Date
    Aug 2005
    Posts
    11,834
    +1 heavy grease

  7. #7
    I Love my Rize
    Reputation: danoalb's Avatar
    Join Date
    Dec 2005
    Posts
    763

    I rebuild them for the cold

    Shimano hubs are known for "freezing up" in cold. I tear them apart as I have the special tool to get inside and clean them and rebuild them with Lubriplate mag-1 extreme cold grease good to about -60 F. They run like a dream and I use this set up all year around. The easiest was is to get the Morningstar freehub buddy and use their freehub soup winter mix. You can run this all year around and you don't have to take apart the freehub to use it but you will need their alu dust seal as you will have to take the stock one out and you will trash it to use the freehub buddy. Which is a good thing as the stock seals SUCK. The new morningstar seals have a oring seal and seal WAY better than the stock Shimano ones. This method is the BEST setup and the soup is FAR superior to anything made right now. Paul Morningstar is a class act and his stuff is the real deal. Most of the AK ice and snow bikers use his soup. By the way ALL of my Shimano hubs have malfuctioned on me but my brothers worked fine in the cold . It's kinda hit or miss with Shimano's in the cold but the hubs I have had have always missed.

    Morningstar freehub buddy...... http://www.morningstartools.com/freehub_buddy1.html
    Early to bed early to RIZE makes a man healthy, wealthy <(scratch that) and wize.

    RIGHTY on a LEFTY

  8. #8
    mtbr member
    Reputation:
    Join Date
    Aug 2008
    Posts
    170
    danoalb, thanks for the input and I'll try this. I'm confident it will fix my problem since you've had success.

    E

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •