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  1. #1
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    Shimano cold weather woes...

    Anyone have any experience with the cold wearther problems from which shimano brakes suffer..The specific problem being pumping up in cold weather where they drag on the rotor.

    Shimano acknowledges this issue but has no solution. Was wondering if anyone out here has had a similar problem, and if you had a solution.

  2. #2
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    I have that problem. I might fix it buy purchasing Maguras.

  3. #3
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    Quote Originally Posted by the Inbred
    I have that problem. I might fix it buy purchasing Maguras.
    yes but you sir can fook off since you have placed me in said predicament...

  4. #4
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    Quote Originally Posted by BThor
    Anyone have any experience with the cold wearther problems from which shimano brakes suffer..The specific problem being pumping up in cold weather where they drag on the rotor.

    Shimano acknowledges this issue but has no solution. Was wondering if anyone out here has had a similar problem, and if you had a solution.
    Just how cold of a weather are we talking about? I have been running XT and LX brakes in 22 degrees without any issues of drag.
    "Winners never quit. Quitters never win. But those who never win and never quit are idiots."

  5. #5
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    23 this morning, 34 tonight.

    How do you transport your bike?

  6. #6
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    I ride mine all winter in NH , no problems
    I dont think mineral oil is affected by temps. in that range, wonder if you got some moisture in there

  7. #7
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    I'm with dan0....

    sounds like you may have a bit of moisture in there. It'll freeze when the lines get cold enough and displace the mineral oil. Basically increasing fluid volume (water expands when it freezes) and setting up the drag.

    With the crazy bunch I ride with the brakes used are everything from BB7 mechanicals on up to Avid Codes, with a sprinkling of Shimano hydros as well. Nobody seems to have any problems. The shimano runners do experience some slow pad retraction problems when the temps drop down into the mid teens. But only after an hour or two of riding. And even then it's only slow retraction of the pads not constant drag.

    I'd say bleed em out and see if that helps.

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  8. #8
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    I'm with the rest of these guys. I think the coldest I've ridden in was in the mid 20's F and I've never noticed any change in performnace of either sets of the shimano brakes I have (XT 4 pot & original XTR).
    Formerly known as iceaxe

  9. #9
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    Quote Originally Posted by BThor
    Anyone have any experience with the cold wearther problems from which shimano brakes suffer..The specific problem being pumping up in cold weather where they drag on the rotor.
    Same here, with BR-M765 and brand new BR-M775. Fixed it by re-bleeding with non-Shimano oil (Yarroline). Probably, Motorex hydraulic fluid will also work.

  10. #10
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    That's interesting to read. I got a call from Shimano today saying that they saw nothing wrong with my brakes, but that they were going to rebleed them and send some new pads. I'll be curious to see if there's any difference in performance.

  11. #11
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    Really quite a simple issue, when the temp gets cold the mineral oil shrinks a bit, the lever pumps a bit more fluid into the caliper.

    Then if the temp warms up a bit it starts to expand and put the brakes on, draggy brakes.
    this is really quite noticable below -16 C (0F), with my XTRs


    My older deores, didn't semm to do this nearly as much, probably because the have more internal volume.

    My fix if it is a problem just pry the pads out with a knife, and keep riding.

    I would think even a tiny amount of air in the system would make this much worse, cause a gas bubble would contract and expand more then mineral oil wrt temperature.
    Last edited by jeffscott; 01-26-2008 at 10:50 PM.

  12. #12
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    Might be useful if you guys actually used temperatures that people internationally understand or at least specify the temperature scale - the difference between 22 and 34 when you reasonably assume Celsius (which everyone but you Americans would) is pretty bloody big - and I wouldn't expect any issues at 22, whereas you would at 34, but with them overheating, not contracting.

    If you're having issues at <0C, you might want to consider letting a bit of fluid out of the brakes (slightly compressing the lever with the bleed nipple open) just to give yourself a little bit more movement - or increase the reach adjustment.
    Quote Originally Posted by tom2304
    Yep farkin.net is mostly immature kids asking how to put dual crown forks on hardtails and such.

  13. #13
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    Quote Originally Posted by akashra
    Might be useful if you guys actually used temperatures that people internationally understand or at least specify the temperature scale - the difference between 22 and 34 when you reasonably assume Celsius (which everyone but you Americans would) is pretty bloody big - and I wouldn't expect any issues at 22, whereas you would at 34, but with them overheating, not contracting.

    If you're having issues at <0C, you might want to consider letting a bit of fluid out of the brakes (slightly compressing the lever with the bleed nipple open) just to give yourself a little bit more movement - or increase the reach adjustment.
    right
    but, this is an American web site isn't it?
    and secondly, what was the title of this thread? cold weather woes? does 22-34 c fall in that category, not bloody likely
    22 c = 71 f so I think its safe to assume that the op was talking Fahrenheit not Celsius
    but dont worry, if you guys ever get a web site in your own country we'll be sure and convert for you

  14. #14
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    Quote Originally Posted by jeffscott
    Really quite a simple issue, when the temp gets cold the mineral oil shrinks a bit, the lever pumps a bit more fluid into the caliper.

    Then if the temp warms up a bit it starts to expand and put the brakes on, draggy brakes.
    this is really quite noticable below -16 C (0F), with my XTRs


    My older deores, didn't semm to do this nearly as much, probably because the have more internal volume.

    My fix if it is a problem just pry the pads out with a knife, and keep riding.

    I would think even a tiny amount of air in the system would make this much worse, cause a gas bubble would contract and expand more then mineral oil wrt temperature.
    wouldnt the fluid shrink throughout creating a vacuum?
    and if the lever pumps more fluid into the caliper it takes it away from the master cylinder, releasing the lever allows it to flow back into the master, cold weather shrinkage would cause less binding not more, as the volume of fluid decreases.
    freezing water increases volume, mineral oil will not freeze at those temps.
    I would say either
    1, water in the fluid or
    2 water freezing around the pistons causing them to bind

  15. #15
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    Quote Originally Posted by dan0
    wouldnt the fluid shrink throughout creating a vacuum?
    and if the lever pumps more fluid into the caliper it takes it away from the master cylinder, releasing the lever allows it to flow back into the master, cold weather shrinkage would cause less binding not more, as the volume of fluid decreases.
    freezing water increases volume, mineral oil will not freeze at those temps.
    I would say either
    1, water in the fluid or
    2 water freezing around the pistons causing them to bind
    Gets cold put the brake on it thinks there as been pad wear, pumps a bit more fluid in, warm it up reduces the clearance gap.

    Simple, take a bike set your brakes up perfect in the garage 15 C, go for a ride at -20 C.

    Bring it back into the garage, bingo brake drag, no mud no roost, no nothing try it.

  16. #16
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    Quote Originally Posted by jeffscott
    Gets cold put the brake on it thinks there as been pad wear, pumps a bit more fluid in, warm it up reduces the clearance gap.

    Simple, take a bike set your brakes up perfect in the garage 15 C, go for a ride at -20 C.

    Bring it back into the garage, bingo brake drag, no mud no roost, no nothing try it.
    set my brakes up on new fork last night (basement temp 20c) rode today 5c
    back in basement, no drag,
    not much for below zero riding, but down to zero and never had any issues
    but if your scenario is right, it should be fine with a couple of squeezes on the lever as that will allow the fluid to return to the master

  17. #17
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    Quote Originally Posted by dan0
    right
    but, this is an American web site isn't it?
    and secondly, what was the title of this thread? cold weather woes? does 22-34 c fall in that category, not bloody likely
    22 c = 71 f so I think its safe to assume that the op was talking Fahrenheit not Celsius
    but dont worry, if you guys ever get a web site in your own country we'll be sure and convert for you
    I think you've missed the point - I'll be more clear for you: America is the laughing stock of the world stage when it comes to scientific measurements. You're the only ones still stuck in the dark ages using imperial measurements.
    As much as the site might be run out of the US, there's a lot of non-US readers hanging around. The international assumption is that things are measured in metric standards, so if we go giving you a wrong answer because you've been too lazy to specify you're using some other measurement, that's hardly our problem
    Quote Originally Posted by tom2304
    Yep farkin.net is mostly immature kids asking how to put dual crown forks on hardtails and such.

  18. #18
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    Quote Originally Posted by akashra
    I think you've missed the point - I'll be more clear for you: America is the laughing stock of the world stage when it comes to scientific measurements. You're the only ones still stuck in the dark ages using imperial measurements.
    As much as the site might be run out of the US, there's a lot of non-US readers hanging around. The international assumption is that things are measured in metric standards, so if we go giving you a wrong answer because you've been too lazy to specify you're using some other measurement, that's hardly our problem
    no, I think you're missing the point
    If I am in your country, I expect to use your measurments, your customs, etc.
    when I go to a UK web site I know the currency will not be us dollars, the temps will be Celsius, etc.
    You cant have it both ways, on the one hand everyone else says we're a laughingstock because of our standards, yet no one expects our standards when on an American site?
    be real
    and tell me who is more of a laughingstock, a country that has become, and still is, the most powerful country on earth, or someone who cant tell that when someone complains about cold weather problems, and lists a range of 24 to 34 degrees? that is is Fahrenheit
    tell me, is 24 Celsius cold? how about 34?

  19. #19
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    Nope you don't get it yet, I have never had the problem above 0 C...

    Try the test it described 15 C to -20 C, problems starts to occur at about -10 C.

    Wiggling the lever to open the port does not work, because there is only the little spring to force the calipers out and this just isn't enough to do it.

    Get a knife stick in between the pad and the caliper and pry, then do the other side, keeps the pisitons from sticking and the the rotors nice and free.

  20. #20
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    Quote Originally Posted by dan0
    no, I think you're missing the point
    If I am in your country, I expect to use your measurments, your customs, etc.
    when I go to a UK web site I know the currency will not be us dollars, the temps will be Celsius, etc.
    You cant have it both ways, on the one hand everyone else says we're a laughingstock because of our standards, yet no one expects our standards when on an American site?
    be real
    and tell me who is more of a laughingstock, a country that has become, and still is, the most powerful country on earth, or someone who cant tell that when someone complains about cold weather problems, and lists a range of 24 to 34 degrees? that is is Fahrenheit
    tell me, is 24 Celsius cold? how about 34?
    A very large proportion of american science and engineering is done in metric...BTW all of the standards of measurement are actually SI, even in the US, hard conversions are applied to English units, in the US like 1 inch equals 25.4mm exactly.

    It is a curtesy to attach units to measurements.

  21. #21
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    Quote Originally Posted by jeffscott
    A very large proportion of american science and engineering is done in metric...BTW all of the standards of measurement are actually SI, even in the US, hard conversions are applied to English units, in the US like 1 inch equals 25.4mm exactly.

    It is a curtesy to attach units to measurements.
    no one was disputing who uses what,
    Akashra was complaining that the op didn't say whether it was Celsius or Fahrenheit, and commenting that America is a laughingstock because we still use Fahrenheit. I was replying to him and I stated that the OP said he was having cold weather problems and the temp was 24-34 , in Celsius that is not cold, so by elimination the temp is Fahrenheit, not hard to figure out

    Originally Posted by akashra
    Might be useful if you guys actually used temperatures that people internationally understand or at least specify the temperature scale - the difference between 22 and 34 when you reasonably assume Celsius (which everyone but you Americans would) is pretty bloody big - and I wouldn't expect any issues at 22, whereas you would at 34, but with them overheating, not contracting.

  22. #22
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    Nothing new, but for the record. My old XTRs(965) work fine at 15 to 20 deg F. They were setup in a ~40 deg F garage.

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