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  1. #1
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    Slight rotor rub on pads.

    Hello,

    I just got an iron Horse warrior 4.0 and I realized on the front and back brakes when i hit the brakes the rotor flexes because the rotor is not centered in the middle of the pads. It actually rubs on one of the pads. What can i do to fix this problem?


    Thanks

  2. #2
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    What brakes are they? A bike model name is only so much help generally...most of us are way too lazy to figure out how that bike might be equipped....
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  3. #3
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    Okay, first off...

    the Tektro Iox brakes that the 4.0 comes stock with are mechanical disc brakes. The rotor most likely won't be centered in the caliper exactly when they are properly set up. And even if the rotor is centered exactly in in the caliper the rotor will still deflect when you apply the brakes. This is because only ONE (the outboard) pad moves when you squeeze the lever. The outboard pad moves inward and forces the rotor into the inboard pad. This is the way they are supposed to work. If I remember correctly, a company by the name of Gusset offers the only dual action (i.e. both pads move when the lever is squeezed) mechanical disc brake on the market. They aren't particularly popular as there isn't enough advantage over other mech disc brakes to make them worth the extra weight. So the rotor deflecting is not part of the problem, nor is it a problem, it's normal.

    As for the rotor rubbing on one of the pads, which pad, the inboard (closest to the hub) or the outboard pad. What you should do about it will depend on which pad it is, and what adjustments the Tektro Ioxs have. Also how bad is the rub. A very slight rub that isn't making a bunch of noise or isn't creating a lot of drag isn't really a problem and with some brakes is more or less normal. Like I said, just depends on the brakes.

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    Last edited by Squash; 12-27-2008 at 03:08 PM.
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  4. #4
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    Interloc's Dual Banger mechanical disc brake also does the dual pad movement, those the same as Gusset? Also, if the OP is just getting intermittent rub it could just be an out of true rotor...
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  5. #5
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    The on pad that moves when you apply the brakes is the one that is rubbing. The wheels don't spin very well but there is not much of a difference unless I am going to do some long XC with the bike.

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    Quote Originally Posted by Bikinfoolferlife
    Interloc's Dual Banger mechanical disc brake also does the dual pad movement, those the same as Gusset? Also, if the OP is just getting intermittent rub it could just be an out of true rotor...

    Your right! Forgot about the dual banger, and nope not the same as the Gussets. Thanks.

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  7. #7
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    Quote Originally Posted by drain bamage
    The on pad that moves when you apply the brakes is the one that is rubbing. The wheels don't spin very well but there is not much of a difference unless I am going to do some long XC with the bike.

    Go to the Tektro website and download the set up manual for your brakes. I believe that both pads on the Io series of brakes are adjustable. Follow the set up/adjustment instructions and you should be able to work it out.

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  8. #8
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    I just tried to adjust them in almost every way i can still they rub.

  9. #9
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    Quote Originally Posted by drain bamage
    I just tried to adjust them in almost every way i can still they rub.
    Exactly what have you tried, though?
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    Lets see I of course twisted in both directions a lot of times the knob the connects the line brakes cord to the caliper and have not noticed anything that changes the pads idle place. I have loosend the bolt that pinches the cable in place and moves when you hit the brakes and still they rub. The rotor is only rubbing on the non stationary pad. i can adjust the stationary one just fine. it is like the rotor needs to be centered itself in the middle of the two pads.

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    Can you recenter the caliper?
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  12. #12
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    Quote Originally Posted by drain bamage
    Lets see I of course twisted in both directions a lot of times the knob the connects the line brakes cord to the caliper and have not noticed anything that changes the pads idle place. I have loosend the bolt that pinches the cable in place and moves when you hit the brakes and still they rub. The rotor is only rubbing on the non stationary pad. i can adjust the stationary one just fine. it is like the rotor needs to be centered itself in the middle of the two pads.
    Are you following the manual instructions for setup? If the calipers need centering, have you done that?
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  13. #13
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    If your calipers have elongated mounting holes then use them to center the caliper properly. If they don't then use shims to move the caliper the direction you need to.

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    I got rid of the problem for the most part. I think it is fine now. One more Q: What do you guys do to maintain your brakes and how often do you do it?

  15. #15
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    I use mechanical discs, Avid BB7s (and older BBDB's, basically same thing), and once I set the calipers and levers up it's basically dial the pad in for wear occasionally, an occasional fresh housing and/or cable, and change pads when needed (it all depends on the conditions and amount of use, it's not a firm time schedule). Pretty much same thing for my bikes with rim brakes.
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  16. #16
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    Is there anything else I can do to increase braking strength?

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    I just cant get the braking strength I want even when plaing with the knobs on the levers and where the cable meets the brake. I tried everything and still am not getting the strength I want from my brakes. Even when both of the pads are slightely rubbing on the disc!

  18. #18
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    Quote Originally Posted by drain bamage
    I just cant get the braking strength I want even when plaing with the knobs on the levers and where the cable meets the brake. I tried everything and still am not getting the strength I want from my brakes. Even when both of the pads are slightely rubbing on the disc!
    Avid mech brakes are extremely 'grabby' and should have plenty of stopping power. I think you have contaminated pads and or rotors, or maybe your pads are just old and worn out.

    Clean the rotors with 100% IPA (or as close to it as you can find). Replace the pads if they are old or if you think there is a chace you got finger oil or some grease on them you can put the pads in the toaster oven on 500 degrees for about a 1/2 hour. I've done this several times. It drives out the oil. YMMV of course depending....

    Another thing...brand new pads also perform poorly. The need to 'bed' before maximum performance can be had.

  19. #19
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    The OP doesn't have the BB7s, I do.

    OP--What have you done to bed the pads in? You might try reading the Disc Brake FAQ in the upper right corner of this page, too....
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  20. #20
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    I have just used them and tried to go down a steep long hill a couple times to get them hot. I have touched the rotors unmerous times. I have never touched the pads. The bike is 1 week old and I ride about average of 10 miles a day just from either riding places or just riding around the neighborhood.

    Just curious what does OP mean?

  21. #21
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    If you touched the rotor with your fingers (the actual outer edge where the pads make contact) then the natural oils on your fingertips have been deposited onto the surface. When the pads closed to slow you down they picked up the oils on the rotor and those slippery oils now form part of your braking surface.

  22. #22
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    OP: OP means original poster.

    I was thinking you had Avid brakes, I know nothing about Tektro brakes, maybe they just don't perform very well, ever. Still, you really need to stop touching the rotor braking surface. Like jmapes said, you have now transfered oil from your hand to your rotors AND pads. This may or may not be the problem but unless you clean the rotors and install clean or new pads ( and bed them in properly) it will be very hard to determine.

    Here's what I would do if I were you:

    1) removed pads
    2) clean rotors with IPA
    3) clean pads with brake cleaner or IPA
    4) put pads in toaster oven for 15 minutes or so at high heat
    5) re-install pads
    6) bring bike up to speed quickly, then brake very hard.
    7) repeat step 6 about 25 times (or more if you are up to it)
    8) see if performance gets better

  23. #23
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    Well thanks for the replies. Today I finally put the brakes up to a little bit more stuff than usual. I took them up the canyon and rode back down using the brakes as much as possible. At the bottom I put a small peice of snow on the disc and it started bubling away in less than 1 second. I have no idea why but for some odd reason it fasinates me to get the brakes very hot.

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    So as you know my final ride weight is 130 lbs (that is my weight plus the weight of the bike) and I saw on the tektro web site you shouldn't go downhilling with these brakes. I assume they test that with probably 200 lbs? Because I plan on in the summer going down a long steep mountain of pure DH (wasatch mountains) You need to take a tram to get to the top because you just cant walk. I have only seen the place to ride down once like 3 years ago when one guy rode the trom up with his mtb. I am wondering if since I am such light weight that I could just use the brakes I currently have to do that run or if that would be just too much for the little brakes to handle. What could possibly happen IF the brakes get too hot going down?

  25. #25
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    I'm sure you'll be fine

    Quote Originally Posted by drain bamage
    So as you know my final ride weight is 130 lbs (that is my weight plus the weight of the bike) and I saw on the tektro web site you shouldn't go downhilling with these brakes. I assume they test that with probably 200 lbs? Because I plan on in the summer going down a long steep mountain of pure DH (wasatch mountains) You need to take a tram to get to the top because you just cant walk. I have only seen the place to ride down once like 3 years ago when one guy rode the trom up with his mtb. I am wondering if since I am such light weight that I could just use the brakes I currently have to do that run or if that would be just too much for the little brakes to handle. What could possibly happen IF the brakes get too hot going down?
    I'm 200 pounds and ride on 6 inch rotors, and only rarely overheat my brakes.

    What happens when you overheat your brakes is they loose their grab. They still work, but they will take much more lever pull for the same stopping power. Eventually, if you push them way too hard is that you'll pull the levers to the bar and there won't be enough to slow the bike down. You'll pretty much know when this starts to happen.

    That said, anybody can overheat brakes. If you put your brakes on and just hold them long enough, they will overheat. The trick is to pulse your brakes. Apply them, let them off for a second, apply them again as you descend. What happens is that the face of the brake pad doesn't get any cooling air rushing by. The holes in the rotors help a bit, but pulsing them works really well. When you let the brakes off for a second, it lets the face of the pad cool off a bit.

    Also, overheating your brakes can glaze them, making them suck.

    Also also... most cable brakes don't do well with adjusting the inline barrel cable adjusters. Usually, this just pulls the brake arm in and can potentially cause the arm to bottom out on the caliper body. Don't use the barrel adjusters to adjust the grab point. To adjust the 'grab' point of the brake, use the pad adjusters. The barrel adjusters should only be used to take up the overall slack in the cable and housing.

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