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  1. #1
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    Road disc brakes 140 or 160 or mix for CX

    I want to add Avid BB7 road disc brakes to a Lemond Poprad disc cyclocross frameset that I bought as a frame only. I hear that some of you guys are running 140 rotors on the rear and 160 rotors on the front. This is my 1st foray into disc brakes; how do you decide on the rotor size? What are the pros and cons? Will the hardware take either 140 or 160s? I am a big guy 220 lbs, so I was assuming 160s (the bigger the better).

  2. #2
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    I'm at 185lbs and I have no problems with running 140's in the rear. BB5's will lock up the tire just fine, don't really need any more leverage from a larger rear rotor.

  3. #3
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    Would Avid BB5s or Tektro Lyra disc brakes be just as effective as BB7s for cross?

    Quote Originally Posted by wrcRS View Post
    I'm at 185lbs and I have no problems with running 140's in the rear. BB5's will lock up the tire just fine, don't really need any more leverage from a larger rear rotor.

  4. #4
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    I'm running the 160/140 setup I'm 170# and using Hayes CX-5s no problems here.

  5. #5
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    Quote Originally Posted by Erik_A View Post
    I want to add Avid BB7 road disc brakes to a Lemond Poprad disc cyclocross frameset that I bought as a frame only. I hear that some of you guys are running 140 rotors on the rear and 160 rotors on the front. This is my 1st foray into disc brakes; how do you decide on the rotor size?
    I briefly ran 160/140 -- Avid BB7s -- on the El Mariachi I built up this spring. I took that approach as an experiment because I was curious to see how it played out. The smaller rotor made it pretty much impossible to inadvertently lock up the rear wheel in a hard stop. I see that as a benefit. However, I really noticed the lack of braking umph in those cases when I purposely tried to stop using just the rear brake. Of course, that's pretty much true of any rotor size, and I really never use the rear brake that way except to experiment.

  6. #6
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    I think for the smaller tires in cross a 140 rotor is fine. I can't speak to Tektro but I have BB5's on my cross bike and they work fine for me. Initial setup was a bit of a pain, nothing I couldn't work through.

  7. #7
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    I read somewhere that the thinner tires for road and cx don't mean jack **** regarding smaller discs and brake power, you want juice you need bigger discs thats it. Something to do with your weight not changing and zero sum game and all that crap. Taking corners is whole nother thing though. Supposedly. I have never had too much brake.
    Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.

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    Specialized sucks ass.

  8. #8
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    Rotor size is more about fade. Decent brakes will lock up 160's with big mountain tires. A typical CX course shouldnt be fading brakes. 140/160 should be fine for nearly all riders. If you find the rear fading, its not expensive or anything to switch up.

  9. #9
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    Quote Originally Posted by Erik_A View Post
    Would Avid BB5s or Tektro Lyra disc brakes be just as effective as BB7s for cross?
    I rode BB5s for about 8 months and once a month they would self adjust so I couldn't stop at all. I think the constant braking torqued the adjustment dial and they became loose. It was really dangerous, so I upgraded to BB7s and haven't had a problem since.

  10. #10
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    Thanks guys

  11. #11
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    I'm 240lbs and the 140/160 work great for me.
    The LPG

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