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  1. #1
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    How powerful is your front brake?

    I just upgraded my front rotor to a 8" (203mm) and haven't been all that impressed yet. Sure it stops better than the original 160mm, it was toast, but it is not throw me over the handlebars powerful. I have tried breaking in the rotor with several 22+ mph-to-0 stops on the front brake only and although braking performance has increased, it's not great.

    In the end, what should I expect out of the front brake?

  2. #2
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    Using a 180 disc with Formula Oro Bianco I can get all my weight over the back wheel and still, without having to pull overly hard, stop hard enough to raise the back wheel off the ground. If I ever needed instant-superman I'm confident it could provide it.

  3. #3
    Double-metric mtb man
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    When you upgraded, did you re-bed the pads to the new rotor? I found that if you take out the pads, sand them slightly as well as true and sand the rotor, when they get bedded in right, there is usually gobs of power. I have to worry about doing a superman and I'm a Clyde running a V8 front rotor on HFX-9's.
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  4. #4
    3 "fiddy" for short
    Reputation: be350ka's Avatar
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    What pads are you using? If you want pure power look into getting some sintered pads.
    You didnt get any brake fluid on the pads or rotor did you?

  5. #5
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    My mono mini pros will lock both wheels with one finger (6" rotors). Hayes nines, xtr, bb7s all do the same.

  6. #6
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    Quote Originally Posted by Psycho Mike
    When you upgraded, did you re-bed the pads to the new rotor? I found that if you take out the pads, sand them slightly as well as true and sand the rotor, when they get bedded in right, there is usually gobs of power. I have to worry about doing a superman and I'm a Clyde running a V8 front rotor on HFX-9's.
    +1 on sanding the pads before bedding them in.

    Plus, if your pads happened to get dirty or oily, clean (cook) or replace them.

  7. #7
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    Steps to installing 8" rotor:
    1) Pull off front wheel and remove 160mm rotor
    2) Install 203mm rotor and caliper adapter
    3) Center caliper on rotor.
    4) Pads are rubbing slightly, so remove caliper and push pistons out
    5) Reinstall caliper and check pads
    6) Pads are rubbing still, so remove caliper and remove pads
    7) Lub pistons and check piston movement
    8) Reinstall pads and reinstall caliper
    9) Pads are too tight so remove caliper, remove pads, reset pistons
    10) Uh oh. Air slipped past the piston and is now in the line.
    11) Bleed brakes
    12) Filler bottle falls off and spreads brake fluid all over caliper, rotor, and fork.
    13) Start again and bleed brakes
    14) Filler bottle falls off and spreads brake fluid all over caliper, rotor, and fork.
    15) Curse repeatedly and go get a beer
    16) Repeat actions 4 times

    I finally bleed the brakes and remove the air in the lines. Pads contact rotor correctly. Most of the brake fluid is cleaned up. The pads have been cooked twice now (literally set on fire). Rotor has been cleaned several times. A hard pull only yields a quick slow down. There certainly isn't throw-you-over-the-handlebars performance.

  8. #8
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    Quote Originally Posted by Lumbee1
    Steps to installing 8" rotor:
    1) Pull off front wheel and remove 160mm rotor
    2) Install 203mm rotor and caliper adapter
    3) Center caliper on rotor.
    4) Pads are rubbing slightly, so remove caliper and push pistons out
    5) Reinstall caliper and check pads
    6) Pads are rubbing still, so remove caliper and remove pads
    7) Lub pistons and check piston movement
    8) Reinstall pads and reinstall caliper
    9) Pads are too tight so remove caliper, remove pads, reset pistons
    10) Uh oh. Air slipped past the piston and is now in the line.
    11) Bleed brakes
    12) Filler bottle falls off and spreads brake fluid all over caliper, rotor, and fork.
    13) Start again and bleed brakes
    14) Filler bottle falls off and spreads brake fluid all over caliper, rotor, and fork.
    15) Curse repeatedly and go get a beer
    16) Repeat actions 4 times

    I finally bleed the brakes and remove the air in the lines. Pads contact rotor correctly. Most of the brake fluid is cleaned up. The pads have been cooked twice now (literally set on fire). Rotor has been cleaned several times. A hard pull only yields a quick slow down. There certainly isn't throw-you-over-the-handlebars performance.
    after all that were they bedded in again?
    And you cleaned the rotors with rubbing alcohol? (FYI - Brake Kleen seems to leave a coating on the rotors, alcohol doesn't)

  9. #9
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    Quote Originally Posted by fsrxc
    after all that were they bedded in again?
    And you cleaned the rotors with rubbing alcohol? (FYI - Brake Kleen seems to leave a coating on the rotors, alcohol doesn't)
    The rotors were cleaned as least three times with denatured alcohol. The pads were cleaned three times as well (last time with denatured alcohol and fire).

  10. #10
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    I weigh 230lbs, and have the stock Avid Juicy 7 with 203/185 rotors on a my 07 Stumpy FSR. I only use my middle fingers when braking during descents, and I can lock up the wheels if needed.
    1997 Specialized Stumpy Pro
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  11. #11
    Look at the time!
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    Quote Originally Posted by Lumbee1
    The rotors were cleaned as least three times with denatured alcohol. The pads were cleaned three times as well (last time with denatured alcohol and fire).
    get new pads. This will either solve the issue, in which case you can throw away the old pads. or it won't, in which case you still haven't wasted any money because everybody needs replacement pads at some point anyway.
    wanted: Cannondale Lefty w/ V-brake studs

  12. #12
    3 "fiddy" for short
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    Quote Originally Posted by Lumbee1
    The rotors were cleaned as least three times with denatured alcohol. The pads were cleaned three times as well (last time with denatured alcohol and fire).
    I agree with the "get new pads" statements. Go with sintered for better stopping power.

  13. #13
    The plough
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    I get so much power from my front brake on a 203 mm rotor that I have to be really careful during fast ROAD descents, while using just my index finger for braking. The stopping power is immense and in some ways disconcerting as I lose speed so fast that it unbalances the bike (fast = stable, slow = less stable) so I have to be really careful to rebalance my weight when slowing down.

    On dirt I just lose the front wheel traction if I am too eager.

    I weigh 210lb + bike.

    V.

  14. #14
    Spring! Spring! Spring!
    Reputation: bear's Avatar
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    I went 203 this year (Magura Louise not Hope though).

    Seated stoppies on hardpack, one finger action. I can't imagine your calipers would yield any less performance (I could be wrong, and while I love my Maggies I can't quite be that much of an equipment snob).

    Something gotta be wrong with the pads or rotors, +2 on just replacing the known-contaminated pads.

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