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  1. #1
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    bb7 brake advice?

    Hello - I was about to buy the Avid BB7 brakes online for my mtb:

    Universal Cycles -- Avid Mountain BB7 Disc Brakes 2012

    It looks like there are 3 options:

    * 160mm rotor
    * 180mm rotor
    * 200mm rotor

    I was wondering why there are 3 different options? Do different bikes require different rotor sizes? Do these options allow the buyer to make a tradeoff decision between stopping power and weight? Or is there another reason for the different rotor size options?

  2. #2
    Elitest thrill junkie
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    If you are riding an XC bike on XC trails, a 160mm rotor is usually fine. If you have bigger wheels with more inertia or a trail/all mountain bike, a 180mm front rotor is usually a good idea. If it's a more agressive all-mountain to freeride/downhill bike, a 200mm rotor is usually a good idea, and the rear kind of varies. On most DH bikes it goes to 200mm, but the front does the majority of the braking so you can get away with a smaller rear rotor, especially for riding that isn't full on DH.

    No matter what, you have to make sure you have the correct brake adapter for the rotor size you intend to use.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

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  3. #3
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    Thanks for the info jayem!

    I have a Titus Racer X which is XC but I'm a larger rider at 225 pounds so it seems like 180mm might be a better option than 160mm.

    Of course, is there any disadvantage to going with 200mm? It costs slightly more but is there any disadvantage besides possibly a few extra ounces?

  4. #4
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    Quote Originally Posted by titus View Post
    Thanks for the info jayem!

    I have a Titus Racer X which is XC but I'm a larger rider at 225 pounds so it seems like 180mm might be a better option than 160mm.

    Of course, is there any disadvantage to going with 200mm? It costs slightly more but is there any disadvantage besides possibly a few extra ounces?
    Yep, putting that effective of a stopper on the bike can cause quite a bending moment on the fork, enough that it can "drag" the wheel to one side and the fork backwards a good deal. On many XC forks 200mm is too big and not authorized by the manufactuer, brake mounts and other items may fail. Usually if one is a larger rider and really needs that bigger brake, they need the bigger stronger fork too, like a fox 34 or at least a RS revelation. Even if the fork can take it, the frame may not be able to over time.

    Your thinking is spot on for the most part though, being a heavier rider it's not a bad idea to go to a 180mm rotor. It depends on how effective your current brakes or a 160 is for you. Some pad materials are more "grippy" than others, which is good for stopping, but extended downhills can build up lots of heat, glaze over the rotor, and leave you with reduced braking effectiveness. If this is the case, the bigger rotor will help dissipate heat better, in addition to stopping better. Is it necessary? Just depeneds on your trails, what you ride, how you ride, possibly how heavy you are, etc...
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  5. #5
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    @jayem - thanks for that good info.

    Sounds like 200mm is a bad idea for XC bikes.

    However, it sounds like 180mm is a more robust option than 160mm without any real downside. Do you agree?

  6. #6
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    Quote Originally Posted by titus View Post
    @jayem - thanks for that good info.

    Sounds like 200mm is a bad idea for XC bikes.

    However, it sounds like 180mm is a more robust option than 160mm without any real downside. Do you agree?
    Yep.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  7. #7
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    Quote Originally Posted by titus View Post
    @jayem - thanks for that good info.

    Sounds like 200mm is a bad idea for XC bikes.

    However, it sounds like 180mm is a more robust option than 160mm without any real downside. Do you agree?
    with the bb7's you loose a little bit of modulation as the rotor gets bigger.

  8. #8
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    A bit of modulation is lost with any brakes when you use a larger rotor, because the stopping power is greater for the same lever input. Using just one finger with powerful brakes is a good practice, and getting used to them.

    Other than weight and a steeper modulation curve there are no real downsides to larger rotors that I can think of, and neither of them are major issues.

  9. #9
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    I'm 280 pounds and never had an issue stopping with BB7's and a 180/160 combo.

  10. #10
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    i know you asked about rotors specifically but in case you didnt know... be sure to not buy cheap housing. my experience is alot of (if not all) the difference in power between a 160 and 180mm rotor will be eaten up by housing compression if you arent using good compressionless housing.

  11. #11
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    As someone who has used BB7s for years, if they are set up correctly, 160 rotors will give you plenty of braking power and great modulation for everything except long steep descents.

    Shimano's new Hydraulic brakes (slx, xt, xtr) have even more power and better modulation and the slx can be picked up for about the same price as bb7s.

  12. #12
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    I'm 220# riding XC.
    During the last years I have been running BB7's in my bikes -180F/160R.
    I always use Jagwire stuff in my setups: Stainless Steel teflon coated inners & kevlar-L3 lined housing...real smooth actuation.
    Install them with Avid Speed Dial Ti levers and you will be able to adjust to your preferences, reach & modulation.
    For me its one of the most cost effective alternatives in the market, without cost of good hydraulic brakes.
    my 0.02

  13. #13
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    Yes, I've found 180 front and 160 rear is a good BB7 setup. The 180 reduces the hand effort just enough to be comfortable. I found with 160 up front my hand would start to cramp after a couple hours of up and down riding.

  14. #14
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    Quote Originally Posted by moefosho View Post
    As someone who has used BB7s for years, if they are set up correctly, 160 rotors will give you plenty of braking power and great modulation for everything except long steep descents.

    Shimano's new Hydraulic brakes (slx, xt, xtr) have even more power and better modulation and the slx can be picked up for about the same price as bb7s.
    +1, BB7s are good, but they are almost as expensive as shimano hydros (which are around $200 for a set) once you factor in upgraded levers and fancy cables to make them run really well.

    1) levers are at least $20 for a set
    2) calipers (which do include rotors) are about $130 for a set
    3) jagwire or other higher end cables (not sure if there are two to set, but I think so) $30

    For that price, I would just go shimano SLX or XT which will be about $80 more once you factor in rotors.

  15. #15
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    Quote Originally Posted by goodmojo View Post
    +1, BB7s are good, but they are almost as expensive as shimano hydros (which are around $200 for a set) once you factor in upgraded levers and fancy cables to make them run really well.

    1) levers are at least $20 for a set
    2) calipers (which do include rotors) are about $130 for a set
    3) jagwire or other higher end cables (not sure if there are two to set, but I think so) $30

    For that price, I would just go shimano SLX or XT which will be about $80 more once you factor in rotors.
    I'd say your caliper cost is $20-$30 too high. Not too hard to find calipers for $50-$55 per wheel.

  16. #16
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    The Ebay BB7's are great - about $80 for the set.

  17. #17
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    I go at about 210# and I have 160mm rotors on front and rear of my Heckler and the only time I wanted for larger rotors is on a very long decent and the get heated up and I get some fading/loss of power. I'm going to build up A Blur next year and I will probably go with 180 front, maybe rear as well. BTW, the BB7's I have on my Heckler have been in service since 2002 and are still going strong.

  18. #18
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    I'm 220# now on 180/180 but even at 250# 180/160 served me well. And slx/xt brakes are excelant for the price and it makes sense to me that a Clyde needs the extra braking power hydro provides.

  19. #19
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    Complete Avid BB7 set (includes EVERYTHING):
    BlueSkyCycling.com - 2012 Avid BB7 Disc Brake Combo Kit

    Killer-ass deal!!!
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