Results 1 to 18 of 18
  1. #1
    mtbr member
    Reputation: awai04's Avatar
    Join Date
    Jul 2004
    Posts
    931

    Recommended rotors for XT m785 brakes

    I just ordered a set of m785 brakes, and am now shopping for lightweight but effective compatible 6-bolt rotors in the 160mm and 180mm sizes. Any favored ones? My default is the standard XT RT-76 or the "Ice Tec" RT-86. I'm also wondering which between the two (RT-76 or RT-86) is preferred and why.

    The standard for me is the Hope X2/M4 brakes with the Hope "floating" rotors. I'm trying the newer XT brakes on a newer bike build, simply because they seem like a great deal for the $.
    It's not dirt in my apartment --it's Earth.

  2. #2
    mtbr member
    Reputation: Kiwiplague's Avatar
    Join Date
    Jul 2011
    Posts
    1,090
    If the brakes came with the finned pads, definately get the Ice-tech rotors, as they are designed to compliment each other. Together they will run cooler than if you used solid steel rotors.

  3. #3
    mtbr member
    Reputation: awai04's Avatar
    Join Date
    Jul 2004
    Posts
    931
    Yeah, finned pads. Interesting about the heat dissipation technology. What's so different about the Ice Tec again? From a pure aesthetic POV, I also should have mentioned that I like the Formula rotors as well, which come in exactly the same diameter. That said, they look to be solid steel.
    Attached Images Attached Images  
    It's not dirt in my apartment --it's Earth.

  4. #4
    mtbr member
    Reputation: Kiwiplague's Avatar
    Join Date
    Jul 2011
    Posts
    1,090
    Ice-tech rotors have an aluminium core that helps dissipate heat better than a solid steel rotor. The finned part of the pads are aluminium as well, so also shed heat better. Together, they can help the system run up to 50 degrees (celcius) under heavy use, thereby helping combat brake fade through overheating.
    The calipers themselves have ceramic pistons to help stop heat transfer through to the brake fluid as well.

  5. #5
    mtbr member
    Reputation: awai04's Avatar
    Join Date
    Jul 2004
    Posts
    931
    Ah cool, thanks!
    It's not dirt in my apartment --it's Earth.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Jun 2009
    Posts
    489
    Although the Ice Tec rotors will probably stay cooler under prolonged light to moderate loads with the occaisional heavy load supposedly they melt. A German magazine claimed that they were able to get Ice Tec rotors to melt after 15 or 25 high speed downhill runs in the alps. Interestingly enough another German magazine claimed that XT brakes with icetec rotors and brake pads were able to withstand higher maximum braking forces than Shimano's Saints. There have been a few reports of Ice Tec rotors changing colors and experiencing accelerated wear. However considering how many Ice Tec rotors Shimano has sold the complaints have been minimal. To my knowledge I am not aware of a single report of a retail consumer melting their Ice Tec rotors,although I have seen one or perhaps two reports of accelerated wear on Ice Tec rotors.

  7. #7
    mtbr member
    Reputation: Kiwiplague's Avatar
    Join Date
    Jul 2011
    Posts
    1,090
    Pure aluminium melts at approx 660 celcius/1220 farenheit, and I'm pretty sure it would be an alloy with a slightly higher melting point. I've heard that rotors can hit 300 - 400 celcius and that's at the upper end of the scale. I think if there was a real chance of melting the aluminium part of the rotor we would have heard about it by now from some rather irate riders.

    How would you be able to do 15 - 25 high speed downhill runs in quick enough succession to reach the theoretical melting/failure point of the Ice-tech rotor?

  8. #8
    staike
    Reputation: staikeinthahood's Avatar
    Join Date
    Oct 2008
    Posts
    217
    The boiling point of the mineral oil is 270 degrees celsius if I remember correctly. Most likely they would boil over before the rotor would melt. Would be nice with some kind of proof that they actually melted, sounds a bit weird.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Jul 2010
    Posts
    2,231
    hard to think that an alu core would dissipate heat any better than a steel rotor bolted to an alu hub finned with spokes.

    they do look cool.

  10. #10
    mtbr member
    Reputation:
    Join Date
    Apr 2010
    Posts
    296
    I just got the new XTs and Ice rotors - they are fantastic. Glad I dropped the extra coin over the standard rotors

  11. #11
    rider
    Reputation:
    Join Date
    Jan 2005
    Posts
    2,336
    Quote Originally Posted by bing! View Post
    hard to think that an alu core would dissipate heat any better than a steel rotor bolted to an alu hub finned with spokes.

    they do look cool.
    Bike rotors are stainless steel. Stainless steel transfers & dissipates heat less efficiently than steel or cast iron.
    Abandoned the 26" wheel in May '03

  12. #12
    mtbr member
    Reputation:
    Join Date
    Jul 2010
    Posts
    2,231
    Im skeptical of temp claims with the ICE tech rotors. I bought them as the cost have gone down dramatically, and it made sense to stick to the whole system for almost little added cost.

    The Avid rotors are thicker and will drag without fiddling with freestroke. I tried and actually had to bleed the system of oil a bit. An advantage is that the Shimano rotors are lighter than Avids. You can feel it by hand.

    That said, it a personal choice.

  13. #13
    West Chester, PA
    Reputation:
    Join Date
    Sep 2006
    Posts
    3,174
    What avid rotor and which ice tech are you comparing ? Xt ice tech rotors are heavier than avid g3 and xx.

  14. #14
    mtbr member
    Reputation:
    Join Date
    Jul 2010
    Posts
    2,231
    my opinion on weight is subjective. i didnt weigh them. i did hold them together as i installed the new rotors.

    i had the 185 avid g2cs and just bought the new rt86s in 180.

  15. #15
    mtbr member
    Reputation:
    Join Date
    Jul 2004
    Posts
    895
    I'm using the Formula R1 rotrs as another poster mentioned with my M785's. Its an awesome combination.
    OB1 Kielbasa

    One is good!

  16. #16
    FriendlyNeighborhoodMTBer
    Reputation: kabayan's Avatar
    Join Date
    Oct 2004
    Posts
    181
    Anyone using these brakes with Magura Marta SL rotors or Alligator Windcutter rotors or have insight on whether these rotors would work?
    If you can't play, display.

  17. #17
    mtbr member
    Reputation:
    Join Date
    Oct 2010
    Posts
    641
    ive been using the xt ice tech rotors 203 front and rear on my enduro with avid elixir 7 brakes and have not had any issues due to heat. i will continue to use ice tech rotors until i actually do encounter a problem.
    Juice

  18. #18
    mtbr member
    Reputation:
    Join Date
    Sep 2011
    Posts
    95
    I just purchased the XT brakes and 160/180 Ice Tech rotors for my recent Blur LTC build and have been extremely happy with them. Good deal on the rotors here: BlueSkyCycling.com - Shimano Deore XT RT86 IceTech Disc Brake Rotor 6-Bolt

Posting Permissions

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