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  1. #1
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    New question here. Hydraulic brake oil cooler

    Am looking form some kind of device that fits in to the brake line system and provides cooling for the brake fluid on long desents / lots of hard braking.

    A2Z have one but the website does mention Avid brakes, only Shimano and another brand.

    does any body know of anything for Avid brakes?

    may sound extreme but I some times ride an area with some long STEEP hills and no escape options and on coming traffic

    thanks

    Hay Ewe

  2. #2
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    I saw your other post and the bad advice you were given.

    First, analyze your braking style and if you're constantly on the brakes and/or need something bigger, designed for more heat, or simply bigger rotors. Additionally, LX brakes use mineral oil, which doesn't have the highest temp range of hydraulic fluids. Those brakes are for more XC usage than anything else, and not for the most demanding usage.

    This brake cooler probably never caught on, if it even exists, due to the fact that you want your brakes as simple as possible, and you also want to make sure you select the right ones for the task, not adapting or bandaiding your brakes for an application they weren't designed for. I've seen what you're talking about and it's a way to add more fluid capacity. However, I would never use it because it will never replace the proper brakes for the application.

    Your best option is to source brakes up for this task of high heat and continuous usage, but even the top brake for continuous usage, the Hope V2 vented needs to be used with skill if you're basically being a knucklehead and heating the brakes up that much. You're going to have to get brakes, up rotor size, or look at other factors to match your weight and riding style.
    Last edited by junktrunk; 09-19-2010 at 05:20 AM.

  3. #3
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    i would try using a high quality fluid first.

  4. #4
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    +1 for analyzing technique and +1 for a better fluid. My partner used 183mm/160mm Hope X2s (the XC brakes) in the Alps this year and she had absolutely no problem with pump-up, on either the fast (30mph+), hard-braking high trails or the swoops and switchbacks on lower trails. I used a V2 and an M4 and had no issues either. We have Motul 5.1 fluid in all our brakes.
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  5. #5
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    I thinks the proper tool for the job is required - and the proper tool is not a "brake cooler" but possibly a set of brakes that are more heavy duty (providing the new fluid and alternate braking styles do not fix your issues)

  6. #6
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    The new XTR has a heatsink built into the pads. Just something to think about.

  7. #7
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    It's probably hard to get much more heat dissipation from bicycle disk brakes bolted to an alu frame. Just thinking out loud.

  8. #8
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    The problem with brake fluid cooling is the lack of circulation. How 'bout a loop with a return line from caliper to mastercylinder?

  9. #9
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    Quote Originally Posted by Hay Ewe
    Am looking form some kind of device that fits in to the brake line system and provides cooling for the brake fluid on long desents / lots of hard braking.

    A2Z have one but the website does mention Avid brakes, only Shimano and another brand.

    does any body know of anything for Avid brakes?

    may sound extreme but I some times ride an area with some long STEEP hills and no escape options and on coming traffic

    thanks

    Hay Ewe
    I just bought one to see what really the hell it was, since it costed next to nothing. I haven't tried it because it needs brakes with a banjo type connection to integrate with. Before getting this, I would check if your brake fluid (and line) is actually getting very very hot. If it is, then it might be worth a try.

  10. #10
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    The place that brake fluid boils is in the caliper where the pads are, so Shimano is on the right track with heat sinks at the point where the heat is highest. How about rigging up a water cooler for the brakes using a pressurized water bottle, with hoses rigged to spray directly on the front and rear pads/calipers, the same way they cool the brakes on those big Euro racing trucks.
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  11. #11
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    Spraying water on hot brakes will warp rotors and crack brake pads. Reason they use in race applications is that parts are replaced after every race. So unless you have lots of disposable income to replace rotors and pads after every ride, its not a feasable solution.

  12. #12
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    Shimano brakes...

    Quote Originally Posted by reptilezs
    i would try using a high quality fluid first.
    ... don't really have any options. There is the Shimano mineral oil, or Finish Line mineral oil... and I'll bet they come from the same bottling machine.

    Did you see the new XTR Trail brakes with the heat sink fin on the brake pad? Maybe somebody will do something like this for aftermarket pads. I can't imagine Shimano owns the patent on this, and I'll bet its been thought of before.

    Like others have said.... if you're really smoking your brakes, it is either:

    A) your braking technique. Pulse your brakes to let some air shoot across the friction surface of the pad, and/or go slower down the hill (as in less to dissipate for a given amount of time to get rid of it)

    B) Your brakes aren't up to the task
    1) wrong brake pads. Sintered can make more friction and get rid of more heat
    2) Brakes not maintained (air in lines, old brake fluid, contaminated pads, etc)
    3) Not enough thermal Capacity in your brakes
    a) Rotors too small, or are of a poor design
    b) brake calipers too small

  13. #13
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    Use Motul RBF 600 (Racing Brake Fluid, 600 degree boiling point) available at many motorcycle shops. If that's not enough, switch to larger rotors and organic pads. If that's still not enough, switch to stainless steel brake lines.

  14. #14
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    Quote Originally Posted by watermoccasin
    Use Motul RBF 600 (Racing Brake Fluid, 600 degree boiling point) available at many motorcycle shops. If that's not enough, switch to larger rotors and organic pads. If that's still not enough, switch to stainless steel brake lines.


    Not going to work. You can't use Dot 3/4 brake fluid in a system that requires mineral oil. It damages the seals.

  15. #15
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    Quote Originally Posted by frdfandc
    Not going to work. You can't use Dot 3/4 brake fluid in a system that requires mineral oil. It damages the seals.
    The OP's brakes aren't Shimano, they are Avid. The thread got sidetracked by the discussion of the new Shimano pads and people's short attention spans starting kicking in

  16. #16
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    Quote Originally Posted by boomn
    The OP's brakes aren't Shimano, they are Avid. The thread got sidetracked by the discussion of the new Shimano pads and people's short attention spans starting kicking in
    Avid brakes with the 600.............where's my shoe? I'm going bik......damn I'm hungry.....hey the Simpsons are on.........wha......what are we talkin' bout again?

  17. #17
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    Quote Originally Posted by boomn
    The OP's brakes aren't Shimano, they are Avid. The thread got sidetracked by the discussion of the new Shimano pads and people's short attention spans starting kicking in


    Damn short term attention.

  18. #18
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    Quote Originally Posted by pimpbot

    B) Your brakes aren't up to the task
    1) wrong brake pads. Sintered can make more friction and get rid of more heat
    2) Brakes not maintained (air in lines, old brake fluid, contaminated pads, etc)
    3) Not enough thermal Capacity in your brakes
    a) Rotors too small, or are of a poor design
    b) brake calipers too small

    Sintered pads would actually transfer more heat to the brake fluid because of the metal in it. Orgramic/ceramic pads would help insulate the brake fluid from the heat. Organic pads have a higher friction coefficient in the dry. The advantage of sintered pads is longer life and better braking in wet conditions which didn't seem to be a concern for the OP.

    Of course the heat has to go somewhere so the pads themselves and rotor would be hotter with organics which the OP didn't seem to realize. Heat affecting just the brake fluid isn't the only part of the equation. In fact I would be more worried about heat glazing the pads, warping the rotor before brake fluid. Brake fluid should be able to stand up to the heat created by our MTB brakes IF the fluid is not contaminated with water. Once water enters into the mix then it will play havoc because it will lower the boiling point of dot fluid. It won't mix with mineral oil but it will still be present and can boil.

    My suggestion is bigger, beefier rotors. A relatively cheap solution that works. Same principle as adding heat sinks onto the calliper. More material to absorb the heat and more surface area to dissipate it into the surrounding air.
    Last edited by NonHands; 09-20-2010 at 06:16 PM.

  19. #19
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    We talking about them saints loosing the football game ahahaha
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  20. #20
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    I dunno...

    Quote Originally Posted by NonHands
    Sintered pads would actually transfer more heat to the brake fluid because of the metal in it. Orgramic/ceramic pads would help insulate the brake fluid from the heat. Organic pads have a higher friction coefficient in the dry. The advantage of sintered pads is longer life and better braking in wet conditions which didn't seem to be a concern for the OP.

    Of course the heat has to go somewhere so the pads themselves and rotor would be hotter with organics which the OP didn't seem to realize. Heat affecting just the brake fluid isn't the only part of the equation. In fact I would be more worried about heat glazing the pads, warping the rotor before brake fluid. Brake fluid should be able to stand up to the heat created by our MTB brakes IF the fluid is not contaminated with water. Once water enters into the mix then it will play havoc because it will lower the boiling point of dot fluid. It won't mix with mineral oil but it will still be present and can boil.

    My suggestion is bigger, beefier rotors. A relatively cheap solution that works. Same principle as adding heat sinks onto the calliper. More material to absorb the heat and more surface area to dissipate it into the surrounding air.
    Insulation works both ways. They can heat up faster, but they will cool off faster, too. Shimano and Avid use copper and aluminum brake back plates. My Mono Minis use Phenol pistons, which is a pretty good insulator. Metal pistons would transfer the heat to the fluid. I rode for years on Sintered pads for my Hope Mono Minis (I'm 200-215 pounds depending on my level of fitness) and I hardly ever overheated my brakes, only when I hit them really hard and fast on the crazy long steeps.

    The second I switched to organic pads (all I could find were Hope Organics and my sintered were fried) I started overheating at the drop of a hat. Switched back to Hope Sintered, problem went away. Sintered had way more bite too, in all conditions.

    And standing up to heat... well yeah, but they don't MTB brakes can get way hotter way faster than car brakes (which are not generally designed to be lightweight). While DOT brake fluid is hygroscopic, it shouldn't ever be a problem in MTB brakes because they are sealed from the atmosphere. Car brakes are vented through the reservoir cap, which is now the water vapor gets in there. Still, good to change the brake fluid from time to time to get rid of wear particles.

    We're also assuming that the issue is with the brake fluid is the weak point here. I've only really boiled the brake fluid a couple times... that is, you can feel it expanding in the brake lever to the point of the pressure backing up and putting the caliper into vapor lock. It's more common for me to overheat the rotor and brake pads, glazing them.
    Last edited by pimpbot; 09-20-2010 at 09:18 PM.

  21. #21
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    Use CPU thermal goo from caliper->adapter and adapter->frame ... I did it just for fun on my 160mm rotor on my DH bike's rear and the frame of the bike now gets warm. Not sure how much it helps, because I never got fade before, but without the thermal goo, the frame was always cold, no matter how long a descent.

  22. #22
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    just get bigger rotors and improve your braking technique. no need to invent something crazy. keep it simple.

  23. #23
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    Quote Originally Posted by ettore
    Use CPU thermal goo from caliper->adapter and adapter->frame ... I did it just for fun on my 160mm rotor on my DH bike's rear and the frame of the bike now gets warm. Not sure how much it helps, because I never got fade before, but without the thermal goo, the frame was always cold, no matter how long a descent.

    Given the high thermal mass of your frame relative to the brake components and that fact that you can feel a temperature increase I'd say the thermal goo is removing a fair amount of heat.

    Has anyone else tried this?

  24. #24
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    Quote Originally Posted by watermoccasin
    Use Motul RBF 600 (Racing Brake Fluid, 600 degree boiling point) available at many motorcycle shops. If that's not enough, switch to larger rotors and organic pads. If that's still not enough, switch to stainless steel brake lines.
    Stainless brake lines will not help matters. I love how many like to attribute ungodly improvements to stainless lines, from better feel, to MOAR POWER, and now for heat shedding.

  25. #25
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    Quote Originally Posted by pimpbot
    Insulation works both ways. They can heat up faster, but they will cool off faster, too. Shimano and Avid use copper and aluminum brake back plates. My Mono Minis use Phenol pistons, which is a pretty good insulator. Metal pistons would transfer the heat to the fluid. I rode for years on Sintered pads for my Hope Mono Minis (I'm 200-215 pounds depending on my level of fitness) and I hardly ever overheated my brakes, only when I hit them really hard and fast on the crazy long steeps.

    The second I switched to organic pads (all I could find were Hope Organics and my sintered were fried) I started overheating at the drop of a hat. Switched back to Hope Sintered, problem went away. Sintered had way more bite too, in all conditions.

    And standing up to heat... well yeah, but they don't MTB brakes can get way hotter way faster than car brakes (which are not generally designed to be lightweight). While DOT brake fluid is hygroscopic, it shouldn't ever be a problem in MTB brakes because they are sealed from the atmosphere. Car brakes are vented through the reservoir cap, which is now the water vapor gets in there. Still, good to change the brake fluid from time to time to get rid of wear particles.
    Don't get me wrong, I'm not trying to troll or on a mission to smite down all that disagree with me. I'm just trying to add my 2 cents to this discussion.

    I won't argue with your observations. If this is what you tried and observed then who am I to say it didn't happen. I started with sintered and then went to organics. My observations were that organics performed better at least in the dry. But you know what, that was years ago. You've got me interested in trying sintered again. I have a set that I will slap on, bed in, and test. That being said, your comment about insulation working both ways doesn't make sense to me. I understand what you are saying in the sense that if it would transfer heat to the fluid easily then it would transfer heat away from the fluid easily also.

    Thing is that there is one critical difference between heat being added and heat taken away. In a nutshell, you brake, pads hit the rotor causing friction, friction causes heat, heat spreads around the system.

    Now for the reverse to happen you would need the pads to be touching the rotor for the heat to go from the fluid, to the pad, back to the rotor. Problem is that pads touching rotor = heat. If you're not braking then the pads don't touch the rotor. There is only air in between the pad and rotor and air is a great insulator. The pad itself is not going to do much in terms of transferring the heat from the fluid to the air, sintered or ceramic. The caliper will do a much better job of that.

    The best solution is to mitigate the amount of heat in the first place. So like what was mentioned here before by a few posters, bigger, beefier rotors.

    One last thing. I'm only discussing heat characteristics here which is what the OP was originally talking about. I don't want to get into the sintered vs organic/ceramic performance debate which has been done to death in these forums.

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