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  1. #1
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    Tektro 720 canti brake adjustment question

    Help! My Salsa Casseroll came with a front rack but I left it off to keep the weight down. I have a temporary need for the rack, so I bolted it on the frame tonight. It mounts on the cantilever brake fork studs and the top of the fork. However, when I reconnected the bolts that hold the canti brakes to the fork it caused my Tektro 720 brake pads to close up tightly on the rim. The only way I can get the brakes to work is to back the bolts out so far that I am afraid that they will work loose while riding. As soon as I try to tighten the bolts, it pushes the pads closed. Any suggestions?
    Attached Thumbnails Attached Thumbnails Tektro 720 canti brake adjustment question-salsa-2.jpg  

  2. #2
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    could you loosen the straddle cable on the brakes a little?

  3. #3
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    lengthen the straddle cable and recenter or loosen the brake cable at the hanger.
    I'm assuming the rack moved the calipers further forward, requiring more brake cable.


    Hard to tell from the picture. The salsa is blocking the view of the cyclocross bike.

  4. #4
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    You may be right, but nothing I did while installing the rack should have changed the straddle cable.

    Here's what I did to make it work for now. I noticed that the canti brake bolt had a decent dab of blue Loctite on the threads, so maybe the bolt just doesn't need to be tightened much. If I turned it more than hand-tight, it would cause the brakes pads to bind. So I added more Loctite to the bolt, and just hand-tightened it. Seems to work fine now, but it just doesn't seem right not tightening a bolt any more than that.

  5. #5
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    Lengthen the straddle cable and torque the bolts to spec before you get hurt.

    Follwing the assumption put forth above, putting the rack behind the arms pushed the arms farther away from the brake cable, effectively shortening the cable and pulling the pads closer to the rim even when the lever isn't being pulled. So you need the staddle cable a little longer or, if you don't have enough extra straddle cable, lower the carrier a little - it looks like you should be able to do that in the pic.
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  6. #6
    wim
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    Quote Originally Posted by helios View Post
    putting the rack behind the arms pushed the arms farther away from the brake cable,
    Difficult to see how you could put the rack behind the arms. The rack bracket is almost certainly designed to go in front of the arms, and in such a way so it preserves the small gap between bracket (formerly bolt head) and stud end needed for non-binding operation of the brake arms. If the bracket was indeed mounted behind the arms: there's your problem. BTW, "Components and Wrenching" has more on this.

  7. #7
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    I think wim is correct, also putting the rack behind the arms would also make it so you couldn't use some of the canti brakes that need the spring to go into one of the spring pin holes on the brake boss.

  8. #8
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    As noted, you can't mount the rack behind the brake arms because the springs need to fit in the holes on the brake boss.

    I'm waiting to bring my bike by the LBS, but my current theory is that the mounting bolts are too short with the rack attached. The rack attachment is about 2.5 mm thick. By adding the rack, that makes the bolt effectively 2.5 mm shorter, so when I tightened the bolt, it compressed the spring. Without the rack, perhaps the bolt bottoms out before it reaches the point of compressing the spring.

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