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  1. #1
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    new guardian has brake rub

    The brake is rubbing for just over half a revolution. Do I need to have the wheel and/or rotor trued or do I just need to loosen the caliper slightly. I haven't checked to see which side of the rotor is rubbing. Someone sent my a utube about rotor truing where the guy manually bent the rotor slightly. This doesn't seem quite right to me.

    Advice? I'm so ready to hit the road and break it in.

  2. #2
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    I had the same issue and it seems to be common, but an easy adjustment. Try loosening the caliper enough where you can wiggle it around just a bit. Then pull the brake lever several times and then hold the brake lever firmly while you tighten the caliper. If I remember correctly it took me a couple of tries before all of the rub was gone, but still easier than bleeding the brakes. Bending the rotor does not sound like a good idea to me either.

  3. #3
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    Thanks Doc, I'll give that a try. We LC guys are going to have to pay a visit up north soon.

  4. #4
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    You CAN bend the rotor slightly to true it. They make an official tool just for rotor trueing, but an adjustable end (Cresent) wrench works also.

    Make sure your trueing tool is clean to avoid getting contaminates on the rotor.

  5. #5
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    Come on up! I want to check out Jack Brooks park sometime.

  6. #6
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    Here's my procedure for getting rid of brake rub:
    1) Get a rubber band and loop it around the affected brake's lever. This basically actuates the brake.
    2) Loosen the two caliper mounting bolts slightly. It doesn't take much turning.
    3) Tighten the two bolts back up a quarter to a half turn at a time. Alternate bolts to avoid tweaking the caliper.
    4) Remove rubber band and spin the wheel to check your work.

    I pop the front wheel off pretty often when I have to transport the bike, so the front brake gets this adjustment pretty frequently. I have not had to bend my rotor to correct the rubbing.

    HTH

  7. #7
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    Quote Originally Posted by 3axap View Post
    Here's my procedure for getting rid of brake rub:
    1) Get a rubber band and loop it around the affected brake's lever. This basically actuates the brake.
    2) Loosen the two caliper mounting bolts slightly. It doesn't take much turning.
    3) Tighten the two bolts back up a quarter to a half turn at a time. Alternate bolts to avoid tweaking the caliper.
    4) Remove rubber band and spin the wheel to check your work.

    I pop the front wheel off pretty often when I have to transport the bike, so the front brake gets this adjustment pretty frequently. I have not had to bend my rotor to correct the rubbing.

    HTH
    I tried Doc's method last night, and almost got it. You know I"m going to poke you to come over if I can't get it to work.

  8. #8
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    Quote Originally Posted by bhlass View Post
    I tried Doc's method last night, and almost got it. You know I"m going to poke you to come over if I can't get it to work.
    What 3axap is suggesting is essentially the same thing. I like the rubber band idea, why didn't I think of that! He mentioned another thing that is important that I left out...tighten the caliper bolts alternately a little at a time.

    Another quick thing you can try if that doesn't work is flip the bike over and loosen the skewer. Then wiggle the wheel just a bit to make sure it is seated in the dropout. That may sound silly but I take the front wheel off every time I haul my bike and this has worked like a charm.

  9. #9
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    Almost got it. There's just this one teensy little spot, but it's a good rub. Wiggle the wheel, with brake released I presume. That almost seems like I'd be starting from scratch. I"m pretty confident about the seating, but I will double-check. Presuming the wheel is good, and the caliper is as adjusted as I can get and there's still rub, what do you recommend next?

    I've run across other posts elsewhere that suggest backing off on the pads then compress the handle and readjust. (maybe I just read that wrong.) I could always run the bike to the LBS tomorrow during work, but I'd hate to spend extra $ considering I'm replacing an alternator this weekend.

  10. #10
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    I received my Gaurdian today and am having the same problem.

    Followed the same steps as stated in previous posts. Almost got it but it still rubs. I can see a slight wobble in the rotor.

    I'll try playing with it some more before I attemp the crescent wrench approach.

    Bike looks great and I can't wait to hit the trails.

  11. #11
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    Wheel wiggle worked!!! My roadie was never this difficult. Last minor problem is chain rub against the front derailleur when I'm on the big chainring and small cluster, the rub is less when I'm on the middle ring, all clear on the lower ring. I noticed that the cable seems to be a little slack when on the lower ring, also the derailleur seems to move slightly back towards center ring after I release the gear switch.

  12. #12
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    whoops spoke to soon. Flipped the bike rightside up and wheeled it out, and heard rubbing. crud!!! It looks like the exterior brake pad is angled, but that could be my eyes playing tricks on me due to the viewing angle.

  13. #13
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    Have you ridden the bike yet? You may want to try bedding in the brakes before readjusting them further. That might provide a little more clearance as the pads smooth out. What also helps, sometimes, is to shine a light through the gap between the pads and rotor and check the gap. If the pads aren't parallel to the rotor, you have a higher probability of them rubbing. My rear caliper did this a bit when I first got the bike and the pads weren't parallel to the rotor. As for the front derailleur, mine rubbed a little bit when the big ring was selected and the smallest sprocket in the back. Step 1 to fix this is to properly adjust the cable. I usually use the following order of operations:
    1) Select the smallest chain ring on the front
    2) Wind in the adjuster on the shifter until it bottoms out
    3) Loosen the cable clamp on the derailleur
    4) Pull on the cable until there is no slack
    5) Tighten cable clamp and check shifter operation.
    6) If you're not happy with the derailleur position, go back to the smallest ring and either add slack or tighten up the cable a bit to shift the cage over.

    I also found that bending the rear portion of the cage outward a few millimeters resolved the remaining issue of rubbing only in the largest ring and smallest sprocket combination. That last part I could not cure with cable adjustments.

  14. #14
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    Quote Originally Posted by bhlass View Post
    whoops spoke to soon. Flipped the bike rightside up and wheeled it out, and heard rubbing. crud!!! It looks like the exterior brake pad is angled, but that could be my eyes playing tricks on me due to the viewing angle.
    Again, what 3axap said. Go put a few miles on her and use those brakes a bit.

  15. #15
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    My hobgoblin had terrible rubbing on the rear brake. I did all of the adjustments that others suggested but could not quite get it gone. The rotor appeared to be nearly perfect, about as good as the front. The front brake was silent and performing perfectly so I figured that the rear rotor was 'true enough' and something else must be the problem.

    I noticed how well my front brake felt, good feel with the lever, not too tight but not loose while in comparison the rear lever was tight.

    I compared the front and rear caliper pistons and noticed that the rear was not all the way retracted (I previously thought it was, it was not until comparing that i noticed the difference).

    I tried to push the piston back using various methods found via the interwebs but it would not budge.

    I kept the brake block that was stuck in the front brake when the bike was shipped. I tried to insert it into the rear caliper and could only get it partially in. That combined with the fact that I could not push the caliper back anymore lead me to believe that the rear brake was not bled properly.

    What I ended up doing was very carefully opening the bleed screw on the rear brake lever while I had the brake block in the caliper. I opened it only just enough to get a drop of fluid out and then close it again**. Tried to push the block in some more and repeated the process until I could insert the block into the rear caliper as easily as I could the front.

    This took 3 drops of fluid before it felt right.

    Put everything back together and voilą no more rubbing or squeal and perfect feel on the brake lever.

    About 300 miles later and everything is still perfect.


    ** If you do this note that the avid brakes have D.O.T. brake fluid in them and that is some nasty stuff, do not get it on your skin and make sure to avoid it contacting your bike's paint. If it does, clean it off immediately with isopropyl alcohol. Also there is a possibility you will introduce air into your system this way, if you do you'll have to do a proper bleed.

  16. #16
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    I went and rode it for just over 30 min. I definitely need to make some gearing adjustments. It takes a good deep push to switch the front ring from low to large ring. Too bad it's raining this weekend, otherwise I'd be calling another local Guardian owner to help me setup and ride at Brooks.

  17. #17
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    I had the same brake issues both front and rear rubbing. I was able to fix the rear easily but the front rotor keeps on rubbing slightly. Weird thing is it only rubs slightly when I'm sitting on the saddle riding. When I stand up the rubbing goes away. When I spin the wheel freely there is no rubbing as well.

  18. #18
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    I wear headphones while riding, problem solved . It also drowns out the chain slap on the stays... bonus!!

  19. #19
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    Quote Originally Posted by rod.d View Post
    I wear headphones while riding, problem solved . It also drowns out the chain slap on the stays... bonus!!
    Chain stay protector helps with the noise

  20. #20
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    Quote Originally Posted by mr2turbo200 View Post
    I had the same brake issues both front and rear rubbing. I was able to fix the rear easily but the front rotor keeps on rubbing slightly. Weird thing is it only rubs slightly when I'm sitting on the saddle riding. When I stand up the rubbing goes away. When I spin the wheel freely there is no rubbing as well.
    Make your front skewer really tight (like tighter than you think you should) and I bet the noise will go away. With 9mm QR front wheels on 29ers, the wheel is such a big lever arm that it can flex the front axle slightly in the fork drop-outs if the skewer isn't super tight.


    Jeremy
    Airborne Dude.

  21. #21
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    I tried that and unfortunately it was still rubbing. I had to true the rotor a little bit and now its all good!

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