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  1. #1
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    140mm Rear better for what weight rider?

    I'm 175 lbs, XC riding, some racing. At what weight do you think there is no advantage to 140mm rear rotors? Thinking of just making a switch.
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  2. #2
    Always Learning
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    Quote Originally Posted by bbgobie
    I'm 175 lbs, XC riding, some racing. At what weight do you think there is no advantage to 140mm rear rotors? Thinking of just making a switch.
    I'm 180 - 182 and switched from a 180 f/r [Alligator Windcutters] to a 160f/140r setup [Alligator Windcutters] this season. So far in the training and three races I have been in it has been plenty of rear brake. 180 on the rear was way too much for my needs. But I live in the Midwest, so no long mountains to descend.

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  3. #3
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    I'm over 200 and I rode a hardtail with a 140mm rear rotor for 2 hours before realizing it.

  4. #4
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    Depends a lot on your riding style. I wouldn't think it's so much a power issue (easy to lock up rear wheel on almost any brake) as it is a heat dissapation issue. If you're the kind to drag the rear down long descents then I wouldn't, but at your weight and riding style I would guess that you'd be fine with 140 in the rear.

  5. #5
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    Considering the front brake typically takes about 2x the braking force of the rear, a smaller rotor should be fine. Around here in Michigan we don't have sustained hills to really heat up rotors, but when I did some riding in Montana with 160 rotors front and rear, the front would start to turn blue and the rear would not. I have thought about trying a 140 rotor on the back but so far have not gone for it.

  6. #6
    AKA Frank N. Bike!!
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    How do you fit a caliper to bite a 140mm rotor?
    My Bike: '03 Specialized HardRock FrankenBike
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  7. #7
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    You would use a front 160mm IS-PM rotor for the rear. The front IS mount is 20mm farther from hub than the rear IS mount.

  8. #8
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    The 140mm rotors are best for only breaking uphill

  9. #9
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    THanks guys

    I'm gonna try it out.

    Yes, as mentioned use a front IS adapter on the rear.
    www.mtbiker.ca

    My Rides:
    FSR XC -R7 Platinum - SRAM X7 (26.5lbs)
    Cervelo SLC - SRAM Rival - Reynolds DV46T (16.25 lbs)

  10. #10
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    I had to trim the tabs on the pad off on mine, you might too.

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