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  1. #1
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    Stopping Power with 160mm Rotors

    I'm curious is I need to upgrade to larger rotors to get better stopping power. For example, will I have stronger brakes if I go from a Juicy Three to a Juicy Five or Seven, but use the same size rotor? Would I be better off just putting larger rotors on? Also my current front fork recommends a 160mm rotor size, what could potentially happen if I was to use a 185mm rotor?

    I ride a Cannondale 29er and am a Clyde sized guy, I feel like I need more stopping power though. Most likely I won't upgrade until next season, it may be a confidence/experience issue.

  2. #2
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    Larger dia rotors give the brake caliper more torque to slow the hub/wheel. Also, being larger, the rotor can dissipate the heat quicker. You can use an adaptor and run a 203 rotor on the Cannondale lefty. I did this for several years. I like the 203 rotor on the front!

  3. #3
    Bicyclochondriac.
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    Quote Originally Posted by ALS650L
    I'm curious is I need to upgrade to larger rotors to get better stopping power. For example, will I have stronger brakes if I go from a Juicy Three to a Juicy Five or Seven, but use the same size rotor? Would I be better off just putting larger rotors on? Also my current front fork recommends a 160mm rotor size, what could potentially happen if I was to use a 185mm rotor?

    I ride a Cannondale 29er and am a Clyde sized guy, I feel like I need more stopping power though. Most likely I won't upgrade until next season, it may be a confidence/experience issue.
    A larger rotor will definitely help, and in your case (big guy on 29" wheels) I would definitely look into a larger rotor in the front.

  4. #4
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    I figured a larger rotor would be the way to go. I have the 29er 4 so I have a standard RockShox fork on it, not a lefty.

    Say I ride a bike with Juicy Three's, then hope on an identical bike equipped with Juicy Fives, all other variables the same, what difference am I going to notice between the two? I'm trying to figure out if I should use 185mm rotors with my Juicy Three's or if upgrading to a "better" brake with 160mm rotor will get me the same benefits.

  5. #5
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    Bigger rotor will give you more of the same. A different brake or even pads will give you a different feel.

  6. #6
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    The three, five, and seven (and BB7 for that matter) all use the same brake pad. The differences as you move up in number are mainly weight and adjustibility, not power. A larger rotor on a three will give you more outright power than a smaller rotor on a seven.

  7. #7
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    I was looking at my bike and it doesn't look like a 185mm rotor will fit on the rear, I think it will hit the chain stay, if that's the correct term. On the front my Dart3 only recommends a 160mm rotor. What could potentially go wrong if I put a bigger rotor on the front?

  8. #8
    Bearded highlighter
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    I put a 203 BB7 on my 2009 Dart 3 29er and had bad flex issues even on the road. I only weigh around 130lbs loaded, so i wouldnt do it.

  9. #9
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    Quote Originally Posted by ALS650L
    On the front my Dart3 only recommends a 160mm rotor. What could potentially go wrong if I put a bigger rotor on the front?
    Correct me if I'm wrong, but I believe you could possibly wrench the hub/wheel out of the fork dropouts under hard braking.

  10. #10
    Meh.
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    I have seen a Dart with broken dropouts. I would not run larger than a 160mm rotor.

    Though the J3, J5 and J7 use the same pads, I doubt the J3 uses the same size piston in the caliper. This means that the hydraulic advantage is different. So it does indeed produce a different amount of power. The general feel and performance of a J5 is far better than that of a J3 anyways.

  11. #11
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    Having my fork rip apart underneath me doesn't sound like fun. I guess I'll stick with what I have for now. I knew that when I purchased the bike the fork wasn't ideal for somebody my size, I weigh about 245lbs. I guess instead of masking my lack of skills with good parts I'll have to learn to ride better Thanks for the info guys.

  12. #12
    AKA Frank N. Bike!!
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    Sounds like you need a Marazoochi DJ 2 or 3...
    My Bike: '03 Specialized HardRock FrankenBike
    My Blog: http://http://kona0197.wordpress.com/

  13. #13
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    Just FYI, I rode a cheap bike today with 140mm Disks front and back and the darn thing almost put me over the handle bars. I didn't expect much as the rotors looked really cute, but whole cow...!

    But after a short ride (less than 5 minutes) the disks where unusually hot, more than mine at least...

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