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  1. #1
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    Getting better power out of brakes...

    Avid BB5 again......................

    I changed the pads(bedded in,Semi-Metallic), changed the rotor(Avid G3), changed cable. I still don't get decent power out of the brakes. I can't do a one finger stop and lift the rear wheel, and very hard even with 2 fingers.

    Compared to some old 14inch kids bike, fitted with some new promax v brakes and new pads, they are like 2x better stopping power and feel - I can do a full stop by a quick lever pull and not too hard either.

    Currently using avid FR-5 levers. Would upgrading to the Speed dial levers give me more power and one or two finger braking?

    Might upgrade to BB7 next year if I can't get decent power out of these, and have enough money.

    Thanks in advanced.

  2. #2
    rebmem rbtm
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    The G2 would of been a better choice of rotor then the G3.

  3. #3
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    Well, I just had the roundagon and G3 as spare so put the G3 on front.

  4. #4
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    Quote Originally Posted by bikeman1 View Post
    Avid BB5 again......................

    I changed the pads(bedded in,Semi-Metallic), changed the rotor(Avid G3), changed cable. I still don't get decent power out of the brakes. I can't do a one finger stop and lift the rear wheel, and very hard even with 2 fingers.

    Compared to some old 14inch kids bike, fitted with some new promax v brakes and new pads, they are like 2x better stopping power and feel - I can do a full stop by a quick lever pull and not too hard either.

    Currently using avid FR-5 levers. Would upgrading to the Speed dial levers give me more power and one or two finger braking?

    Might upgrade to BB7 next year if I can't get decent power out of these, and have enough money.

    Thanks in advanced.
    No upgrading the levers is not going to give you an increase in braking power. And going to a different rotor of the same size as the original usually doesn't result in much of an increase either. Increasing rotor size and going with a different pad compound (which you've already done) are usually the best ways to get more bite from the brakes. So, what size rotor are you running. If you're using a 160mm up front, then bump up to a 185. Once bedded a 185 will give you noticeably more bite. If not, then there's something wrong with your set up.

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  5. #5
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    Mechanical disc brake power is directly proportional to the amount of flex the rotor sees while braking. Obviously these are single moving piston systems so there will be an inherent amount of flex needed but minimizing it is the key to power.

    In an Avid system, your rotor can flex in three major ways: bending in toward the fixed pad, twisting through the pads, and what I'll call folding through the pads. Remember, in all of these examples, a millimeter of movement is a very significant amount of movement.

    Bending in toward the pads is the most common and the one that you need to keep constant adjustment of through the life of your pads. To adjust this, keep the fixed pad as close to the rotor as you can without excessive rubbing. Sometimes that means dealing with a little bit of rub to keep the brake running strong.

    Twisting through the pads: let's say you're looking down at the slot in the back of the caliper while you squeeze the brake lever. If the rotor is making an "S" shape while you pull the lever then you're loosing power. Adjust the caliper such that the rotor no longer needs to snake between the pads and instead runs straight through the caliper.

    Folding the rotor: hard to describe, but let's say you're looking at your bike's rear brake from the back of the bike. Let's say the caliper is roughly at the 12 o'clock position. The rotor can also bend like the top of the rotor is being folded over into a little hook. This is actually hard to see when you squeeze the lever so what you want to check is if both brake pads hit square onto the rotor. You don't want the top edge or the bottom edge of the moving pad to contact the rotor, you want the pad to hit the whole surface against the rotor at once.

    The Avid CPS system is the worst thing to happen to bike brakes since... I can't think of anything witty because I think I'd rather run coaster brakes than keep the CPS on an Avid brake. The CPS system is the stack of conical washers that allow the brake to adjust to all the crazy angles of frames out there and get the pads to contact the rotor square. In practice, however, frames are built to much higher tolerances than they used to be and the CPS washers actually cause the caliper to go out of alignment while you tighten down the caliper fixing bolts. You can minimize this by putting a little bit of lube on the concial washers and even sanding their surface smooth if you want to get really crazy. Tighten any Avid brake down very slowly working back and forth from bolt to bolt for the best result.

    Good luck!
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  6. #6
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    New Avid pads can require a very long time to bed in.

  7. #7
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    The rotor still flexes the very slightest, so will move the actuating arm down a bit and screw in the pad adjuster.

  8. #8
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    Don't think of flex as flex, it's the power wasted to continually warp the disk as it passes through the pads, so yeah keep that to a min, check the facing is good to so the pad contacts the disk flat, having the continually warp the disk to allow for this wastes a lot of hand strength.

  9. #9
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    just wanted to point out, that just since you can endo on a kids bike doesn't mean that it has superior braking power. I'm sure the cheapest brake out their could endo you pretty easy on a road bike compared to a nice break on a long travel mountain bike.

    Although, i have the bb5s on my ht and haven't been to satisfied either. its all about getting them dialed in to the least amount of rub and the most braking. IME i have had to sacrifice one or the other, and i usually opt for a little bit of rub for more braking power.

    i am not an experienced bike mechanic or bike expert though, its just what has worked for me

  10. #10
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    Off topic:

    I just thought my rotor might have some oil on it from last time they got contaminated.

    I followed my friends method and squirted Kerosene on the rotor. Went for a ride, and they were stopping slightly worse (SOOOOOOOOOOOO LOUD). You could see black oils on the rotor from kerosene and maybe old contamination. Then put some water on it, slight squeaking and 2X stopping power. Wiped off the rotor, it was squeaking and worse like before. More water, less squeaking heaps more power! Just left it for 20mins without wiping (some grime on there) come back and awesome stopping power! I suggest this method if your pads/rotors are contaminated. Just need to fine a nice long downhill to burn off the rest of oil (very fine oil) from kerosene.


    Back to main topic:

    I'll see if I still get good power when completely dry tomorrow.

    Also readjusted and removed caliper from bike. Then put the torque arm to rest position, screwed in inboard pad adjuster. Then put the caliper on the bike (had to back out pad adjuster just so it fit in). Then hold brake lever and tight CPS. After, tightened, I screwed the pad adjuster so the wheel could spin but it was touching pads heaps (was in a rush, so couldn't do perfect). Used the barrel adjuster a bit so didn't have to pull brake past halfway, and after that, it worked great (Still had to more torque arm up a tiny bit - will readjust later).

    So they are working better but still cant seem to do a 2 finger stop yet, but can with 3 fingers quite easily. Does it matter what way the pads are put in? eg one for outboard side and one for inboard?

  11. #11
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    Just curious - have you thought about moving to hydro's - the new XT brakes are superb with an excellent price point.

  12. #12
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    Don't plan on that at the moment, might in the future.

    How do BB5's compare in stopping power and feel to the Tektro Auriga Comp hyrdo's?

  13. #13
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    Quote Originally Posted by bikeman1 View Post
    ...I just thought my rotor might have some oil on it from last time they got contaminated.

    I followed my friends method and squirted Kerosene on the rotor. Went for a ride, and they were stopping slightly worse (SOOOOOOOOOOOO LOUD). You could see black oils on the rotor from kerosene and maybe old contamination. Then put some water on it, slight squeaking and 2X stopping power. Wiped off the rotor, it was squeaking and worse like before. More water, less squeaking heaps more power! Just left it for 20mins without wiping (some grime on there) come back and awesome stopping power! I suggest this method if your pads/rotors are contaminated. Just need to fine a nice long downhill to burn off the rest of oil (very fine oil) from kerosene...


    I would suggest trying new pads after cleaning the rotor with alcohol or brake cleaner.

  14. #14
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    Its crazy but it works great.

  15. #15
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    Also realized that the pads aren't grabbing on 5mm of the disc. The CPS washers are correct.

  16. #16
    rebmem rbtm
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    Also realized that the pads aren't grabbing on 5mm of the disc.
    What exactly do you mean, are the pads overhanging the outer edge of disc by 5mm ?

  17. #17
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    Quote Originally Posted by zebrahum View Post

    The Avid CPS system is the worst thing to happen to bike brakes since... I can't think of anything witty because I think I'd rather run coaster brakes than keep the CPS on an Avid brake. The CPS system is the stack of conical washers that allow the brake to adjust to all the crazy angles of frames out there and get the pads to contact the rotor square. In practice, however, frames are built to much higher tolerances than they used to be and the CPS washers actually cause the caliper to go out of alignment while you tighten down the caliper fixing bolts. You can minimize this by putting a little bit of lube on the concial washers and even sanding their surface smooth if you want to get really crazy. Tighten any Avid brake down very slowly working back and forth from bolt to bolt for the best result.

    Good luck!
    You are the only one besides myself who seems to see this. I use a piece of poly milk carton between the pad and rotor to let the caliper slip down along the rotor as it is tightened. And i don't squeeze hard on the lever as I tighten.

    I would like to see jack screws to push against the calipar mounting screws. Would make adjustment and repeatability a whole lot easier.

  18. #18
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    Quote Originally Posted by cobba View Post
    What exactly do you mean, are the pads overhanging the outer edge of disc by 5mm ?
    The pads are leaving a 5mm gap on the bottom of the rotor. You can see the pads are grabbing on the bulk of it, but you see there is a gap that shows the pads aren't grabbing fully. The bulk of the rotor is darker which shows the pads aren't grabbing on the bottom as the bottom is much lighter and shows marks from sanding it previously.

    Can post pics if needed.

  19. #19
    rebmem rbtm
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    Quote Originally Posted by bikeman1 View Post
    Can post pics if needed.
    That would be a good way to see what's going on.

  20. #20
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    Sorry for late reply, I don't have my good camera so had to take on my iPod.

    You can't really see it but if you look at the bottom part of the rotor, you see it is not being used and same with the top curves.

    I'm sure this is probably because the rotor is not designed for the disc.



    EDIT: sorry, forgot to attach image
    Attached Thumbnails Attached Thumbnails Getting better power out of brakes...-img_0217.jpg  

    Last edited by bikeman1; 10-01-2011 at 08:14 PM.

  21. #21
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    Quote Originally Posted by bikeman1 View Post
    Avid BB5 again........I still don't get decent power out of the brakes...
    Quote Originally Posted by bikeman1 View Post
    ...I just thought my rotor might have some oil on it from last time they got contaminated.

    I followed my friends method and squirted Kerosene on the rotor. Went for a ride, and they were stopping slightly worse (SOOOOOOOOOOOO LOUD). You could see black oils on the rotor from kerosene and maybe old contamination. Then put some water on it, slight squeaking and 2X stopping power. Wiped off the rotor, it was squeaking and worse like before. More water, less squeaking heaps more power! Just left it for 20mins without wiping (some grime on there) come back and awesome stopping power! I suggest this method if your pads/rotors are contaminated. Just need to fine a nice long downhill to burn off the rest of oil (very fine oil) from kerosene....
    Quote Originally Posted by bikeman1 View Post
    The pads are leaving a 5mm gap on the bottom of the rotor. You can see the pads are grabbing on the bulk of it, but you see there is a gap that shows the pads aren't grabbing fully. The bulk of the rotor is darker which shows the pads aren't grabbing on the bottom as the bottom is much lighter and shows marks from sanding it previously....
    Am I the only one that sees a problem here?

    I still suggest you start off with new pads and a clean rotor.

  22. #22
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    Pic is too grainy and blurry to see the wear pattern so it doesn't help much. BB5s, once adjusted properly, should give you one finger stopping. Mine did while I had a set on one of my bikes.

    Oh, kerosene or any other petroleum based liquid is not good for brake pads and braking effectiveness. It's crazy, but it doesn't work.
    Everything that kills me, makes me feel alive

  23. #23
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    The Kerosene gave my friend better than new stopping power. He soaked his pads in kero, scrubbed rotor with kero, went down quite a huge hill, at the end smoke was coming off and his power was better than new (easy one finger stop).

    I can get good stopping power when water is on it, but when it dries off, its really crap and squeaks like crazy. I'll try the same hill, and if no good, then i'll change the pads.


    When you adjusted your BB5's Malibu412, was the torque arm at rest or did you pull it up with the cable to a higher position (How it's done in the bluecollar guide)?

  24. #24
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    Also in the bluecollar guide, the torque arm is raised so the outboard pad is closer. Should I do the same?

    And also there are no CPS bolts installed in the guide.. Don't you need these or should I do it without?

  25. #25
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    Quote Originally Posted by bikeman1 View Post
    The Kerosene gave my friend better than new stopping power. He soaked his pads in kero, scrubbed rotor with kero, went down quite a huge hill, at the end smoke was coming off and his power was better than new (easy one finger stop).

    I can get good stopping power when water is on it, but when it dries off, its really crap and squeaks like crazy. I'll try the same hill, and if no good, then i'll change the pads.


    When you adjusted your BB5's Malibu412, was the torque arm at rest or did you pull it up with the cable to a higher position (How it's done in the bluecollar guide)?
    I still say any petroleum based material is not good for brakes but that's just me...and millions of others. Also, that Avid rotor and your BB5 calipers/pads should match up fine once you have the correct washers and alignment.

    With my optimum adjustment, I usually had the arm pulled up away from full open just a small amount as part of the outer pad adjustment and to keep the lever pull short enough. The back pad is adjusted with the red knob, of course.
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