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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.

  26. #26
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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.
    Dude - that is a freakin' excellent idea. If you can make your frame warm to the touch then that's very significant. Not to mention that the goo (Thermal Interface Material - TIM) might well benefit the vibration/noise characteristics of the caliper/pad. I can't believe I've never heard of that before. Good one.

  27. #27
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    Quote Originally Posted by junktrunk
    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.
    Stainless brake lines absolutely DO help with heat management. Look into their widespread use in motorsports. The physics is really simple - the metal acts as a heat sink and radiator, especially at the larger-than-stock metal banjo connector. I've never felt the need for one on my downhill mountain bikes, but I felt a significant reduction in heat fade on the front brake of my motocross bike when I switched to a stainless line.

  28. #28
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    Good points...

    Quote Originally Posted by NonHands
    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.
    ... but if the point of failure is the boiling brake fluid then yes, you are right. If the point of failure is the pad overheating and glazing (basically, burning off the epoxy that holds it together, reducing brake friction) then a pad that cools off faster is better. Shimano and Avid both use copper backed pads, and copper is an excellent conductor of heat. Wonder why?

    And I'll say it again: Hope uses Phenol (which is sort of a plastic-like material) pistons which act like heat insulators, so the heat doesn't transfer into the caliper as much. I had my Hope Mono Minis for a 18 months when they developed badly sticking pistons. I called Hope about it, asking how this is fixed. They just said 'send them in, we'll take care of it for you' even thought I was six months out of warranty. They replaced the original pistons with Phenol pistons... so they upgraded at some point in 2005 or so.

    Hmmmm interesting read:

    http://en.wikipedia.org/wiki/Phenol

    Heh... never tried ceramic pads. How well do those work? I think I heard somewhere that they have very little bite, but last forever. Is this true? Might be good for a touring bike, where crazy brake performance isn't so important, but lasting 1000 miles might be.

  29. #29
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    thanks for the replies, some interesting ones there.

    I am running organic pads and the conditions were dry at the time. Ambeint air tempreture woudl have been around 30deg Celcius.

    I run two sets of wheels on my bike, a racing pair and a training pair. My wife also has the same wheels and so to upgrade to larger rotors would be a new bracket and larger disk, three times (just for front wheel) we like to keep things similar for compatability and ease of use. Whilst I understand that this would assist in solving things, the cost doesnt fit my financial way of thinking.

    I had seen the shimano brakes with the extra fins for heat sink, but I wont be upgrading to them just for the sake of upgrading, that doesn't work with my financial logic.

    I had already analysed a number of factors, larger brake rotors, the type of pads being used, and the weak point was the fluid, it was about 6 months old and when I changed it it had a very burnt color. the pistons are plastic type (do Avid use phenol?)

    After considering the above and changing the brake fluid for new (using the SRAM brake fluid), which I had already done, I actually consider the installation of an additional reservoir / radiator / cooling device to be the easiest solution.

    I shall take time to research proper braking techniqe as well.

    thanks

    Hay Ewe

  30. #30
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    Quote Originally Posted by the-one1
    The new XTR has a heatsink built into the pads. Just something to think about.

    Why does that heat sink look like cheap plastic?

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    Heat sinks don't need to be out of metal. They just need to conduct heat and have that surface area.

    However, I don't know if that is out of plastic. If not, then rough cast and paint it, and you have metal that looks like plastic to some dude on the internet.

  32. #32
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    Quote Originally Posted by pimpbot
    Heh... never tried ceramic pads. How well do those work? I think I heard somewhere that they have very little bite, but last forever. Is this true? Might be good for a touring bike, where crazy brake performance isn't so important, but lasting 1000 miles might be.
    The ceramic pads were from Discobrakes which unfortunately didn't perform well. Possibly could have gotten a bad set but I'm not willing to spend more money to test out that possibility. I wrote a review here, just do a search for Discobrakes. So I'm going to say I don't know how ceramic pads perform. I'm interested in trying out the downhill ceramic pads from EBC but it's getting cold up here where I live so I think that is going to be for next season.

    I did have time to test out my Avid OEM sintered pads vs my Koolstop organic pads (they might be ceramic organic pads but Koolstop doesn't really state anywhere what they are exactly).

    In a nutshell I would say this. The organics give the most powerful stopping with one caveat. They need to be warmed up to work at full potential. From cold they stop worse than sintered. If your biking on a relatively flat and straight path then you might not use the brakes enough to keep the organics warm. Keep in mind when cold they weren't crap, just not as good as sintered. The sintered always gave my the same level of braking power whether it was right from the get go or after a long stint on the brakes. It's just the braking power wasn't as high as the organics at full potential. I wasn't able to test but I would assume that sintered still work better in the wet.

    The ceramics are supposed to last the least longest vs sintered. Can't really tell because I have yet to go through a set of organics and sintered (I like to play around with different pads) but I did try sanding my pads using a random orbital sander and 800 grit sand paper and it took off quite a bit of the organic pad material with just a little touch while the sintered one I could hold down a little bit longer before it took the layer of glazing. Not conclusive but interesting nevertheless.

    By the way, sorry for sidetracking this thread.

  33. #33
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    If the problem is boiling fluid and not overheating pads, then heatsink grease between the pad and piston will transfer more heat into the fluid and make things worse. Grease between the caliper body and frame will help, but only if you sand off the paint and only if the caliper body actually gets hot.

    Instead of making a cooler, what you really need is a recirculating fluid system with a series of check valves. Fluid goes into the caliper via the main hole, and comes out the bleed hole and gets dumped or recirculated somewhere else. The check valves prevent the hot fluid from going back into the caliper.

  34. #34
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    lol @ whomever said bicycle brakes get hotter than car brakes.

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    No, you don't need all this bull****e. You just need airflow through the pads and disc, surface area, and ways to allow the heat to shed once it gets into the fluid beyond the resistance of the materials, like hope does, using composite pistons, but inevitably, the fluid will heat up, which is shed through the caliper's design and airflow through it. It's not that hard, actually, but in bike brakes, seems to be missed.

  36. #36
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    Quote Originally Posted by the-one1
    The new XTR has a heatsink built into the pads. Just something to think about.
    My guess is the XTR heatsink is cast aluminum. Apparently black anodizing sheds the most heat. Have a close look at the rotors.... You should be able to see that the rotor is an alloy core with stainless laminate. I think I read somewhere that these stay 5 times cooler than ordinary stainless rotors. I think shedding heat at the rotor is the smartest way to keep things cool and grippy.

    Maybe just buy some XTR rotors?

    b.
    Posting on the basis that ignorance shared is ignorance doubled.

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    Keep in mind a few things

    The rotor sheds the heat. Bigger sheds more heat. Surface area and mass are good things but heavy. I need to look at the vented rotor from Hope. Looks promising.

    The caliper just applies the clamping pressure needed to generate the friction between the pad and the rotor. The rotor carries away and dissipates the heat.

    Sintered metal pads HH rated can operate at higher temps which you should use if you can but can only be used safely in calipers designed for them which have heat insulating pistons. I can boil the fluid in my Hope's in 10 seconds using sintered pads as I have stainless steel pistons. Use organic (not semi-metalic) pads to help insulate regular calipers from heat.

    Example: Sintered pads will boil your fluid fast, semi-metalic kind of fast, organic maybe not at all especially when thick and new. Many folks don't use their brakes anywhere near the limits so they can get away with anything. That is why I expect lots of replies like "I use these and I never boil fluid, everything works fine". The above is for a system being pushed hard.

    Use high temp quality fluid. Motul is good but will not cure a physics problem.

    Once you heat up "boil" the fluid in the caliper you are screwed. You can put any kind of heatsink you want on them. All it does is shorten the recovery time. It still does not stop the problem and boiled fluid is waaaay bad. No stop, run off cliff. I tested big heatsinks bonded directly to the caliper with thermally conductive epoxy and they did really well in reducing the recovery time. Problem is that you have to stop with boiled fluid (not fun!) and then let the fluid cool. The bubbles still form they just go away faster while you are parked at the side of the trail. Ride, stop, recover, repeat. Sintered metal pads are great for this kind of testing as they transfer the heat to the caliper fluid really fast and well.

    The Shimano heatsinks look promissing as they are hopefully preventing the heat from getting to and soaking the caliper.

    I am still looking for bigger more powerful brakes with better heat capacity. Aside from using real brakes off a motorcycle has anyone had any luck with the newer lines of brakes from hope? I am talking real hard use like two people on a bike going down really big long hills again and again. The Laws of Physics are a tough thing and teeny tiny lightweight bike brakes are fighting an uphill battle. :-)

  38. #38
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    Thank you for the replies, interesting to read others thoughts on the subject

    Hay Ewe

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    Hay Ewe, don't you mean thaynk ewe?

    ...reminds me of the joke about the scottish stones cover band. Instead of of Hey you get of a ma cloud...they sand "Hey Mcleod, get off of ma ewe".

  40. #40
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    Quote Originally Posted by watermoccasin
    Stainless brake lines absolutely DO help with heat management. Look into their widespread use in motorsports. The physics is really simple - the metal acts as a heat sink and radiator, especially at the larger-than-stock metal banjo connector. I've never felt the need for one on my downhill mountain bikes, but I felt a significant reduction in heat fade on the front brake of my motocross bike when I switched to a stainless line.
    I ride motorbikes for quite some time now and this is the first time I heard
    that people are putting SS lines on motorbikes to cool down the brake fluid.
    But I could be wrong thinking they they are used to prevent the expansion of the brake line under hard braking.

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    Quote Originally Posted by watermoccasin
    Stainless brake lines absolutely DO help with heat management. Look into their widespread use in motorsports. The physics is really simple - the metal acts as a heat sink and radiator, especially at the larger-than-stock metal banjo connector. I've never felt the need for one on my downhill mountain bikes, but I felt a significant reduction in heat fade on the front brake of my motocross bike when I switched to a stainless line.

    SS lines are not used for heat management in motorsport, there are used because they don't deform like rubber at high temperature.
    If I disagree with you, it's because you are wrong.

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    while on the subject...

    one more thing to add to this since heatsinks and oil coolers have been mentioned.
    What about an air deflector for the front rotor? They are useful in auto applications and I would assume they would have some effect on those downhills.
    Easy to rig up and test. I am surprised it has not been mentioned.


    more metal -> longer to heat up
    Up size those rotors and be done with it. Fiddling with all these exotic solutions and patches is not something that should be done with components as critical as brakes. Keep the testing in the lab!

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    Cooked the brake fluid last night. 8 inch rotors already being used. The rotor cooled really quickly. The calipers contained the heat for quite some time. Took a shot from the water bottle to get the bubbles to go away and everything was good for the next downhill. Yes the system has new Motul fluid. Yes it is bled very well. Nice solid lever until you boil the fluid. Just fighting some basic physics here. Still waiting for the bike market to learn from the motorcycle market on this one. Not new stuff really. Just that the bike industry always errors on the side of uber light and just barely works in this realm.

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    Stevoo, I'd get the Hayes V9 (9 inch) rotor and a quad piston brake (Saint or Stroker Ace) with organic pads. The larger rotor and pads run cooler, plus you have twice as many pistons (and a larger fluid volume) to heat up. If you're running Motul RBF600 (600 deg F boiling point!), I seriously doubt you are boiling the fluid, but other parts of the brake could get hot enough to fade, such as glazing the organic pads.

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    I have a quad or 4 live piston Hope caliper. Yes the fluid boils. I am using Motul fluid but had not seen the new 600 degree stuff. I am definately changing to that. Thanks for the info on the newer fluid. It certainly will help.

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    can you use the new synthetics automotive fluids? There is even a silicone fluid that doesn't eat paint. cheap also.

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    if your system uses mineral oil, can you use the silicone auto fluids? this may have been already answered.

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