bike assembly — front wheel rub

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    • #105566

      I got a new bike this week. I’ll be posting a pic in the "post your rigs" thread, but I’m having one issue I need help with. The bike required some assembly. The problem I am having is my front wheel / brake assembly. After installing the brake caliper and mounting the front wheel, I noticed the tire was not spinning very freely. I removed the caliper because I wanted to run the cable in a different spot. While I had the caliper off, the wheel spun very freely. After re-installing the caliper, the wheel spins more freely, but I can still hear rubbing. Any suggestions?

    • #105567

      Cable or hydraulic? 😄 Later,

    • #105568

      hydraulic — Avid Elixir 5’s w/ 160mm rotors

    • #105569

      Sounds like a bent or out of line rotor. Pry the pads away from the disc and see if the wheel spins freely. Watch the disc as the wheel turns for being off center. This will cause the wheel not to spin freely. Disc braker do drag on the wheel since the pads are in contact with the dics but it shouldn’t be a heavy drag. On hydraulic brakes the piston should retract when the lever is released slightly to prevent too much drag. Confused? I stay that way! 😄 Later,

    • #105570

      If it’s not a bent rotor… are you sure you have the caliper adjusted properly?

    • #105571

      Everything is brand new. Should I have to adjust new calipers? If so, what is involved?

    • #105572

      The clearance on disc brake calipers is really tight and having a rub like that isn’t uncommon when you first set them up. The instructions that come with the Elixirs are great but here’s the jist of what you need to do:

      1. Loosen the CPS bolts just enough so the caliper is free to move side to side relative to the rotor (these are the long bolts with stacks of several washers).

      2. Spin the wheel and while it’s spinning, apply the brakes. Keeping the brake lever locked down, tighten the CPS bolts. You may need a helper but if you have long arms like me, it’s easy enough to reach.

      3. Let go of the brake lever and give the wheel a spin. In theory this will work the first time but if not, start over. If you can see which side of the caliper is dragging, nudge it in the right direction a bit while you’re tightening the bolts down.

      The process usually takes me about 3 tries to whenever I install new brakes but I’m sure it won’t take you that many attempts. 😀

      If you do suspect the rotor is bent or warped it’s easy enough to check – just take it off the wheel and lay it down on a flat surface (a table).

    • #105573

      Have you tried, to push back the pistons?

    • #105574
      "trek7k" wrote

      The clearance on disc brake calipers is really tight and having a rub like that isn’t uncommon when you first set them up. The instructions that come with the Elixirs are great but here’s the jist of what you need to do:

      1. Loosen the CPS bolts just enough so the caliper is free to move side to side relative to the rotor (these are the long bolts with stacks of several washers).

      2. Spin the wheel and while it’s spinning, apply the brakes. Keeping the brake lever locked down, tighten the CPS bolts. You may need a helper but if you have long arms like me, it’s easy enough to reach.

      3. Let go of the brake lever and give the wheel a spin. In theory this will work the first time but if not, start over. If you can see which side of the caliper is dragging, nudge it in the right direction a bit while you’re tightening the bolts down.

      The process usually takes me about 3 tries to whenever I install new brakes but I’m sure it won’t take you that many attempts. 😀

      If you do suspect the rotor is bent or warped it’s easy enough to check – just take it off the wheel and lay it down on a flat surface (a table).

      ^^^^ +1 (Great instructions Trek. You pretty much took the words right out of my mouth…. 😆 )

      I seriously doubt it is a warped rotor, though it may be possible. It does happen!

      On-On!

    • #105575
      "trek7k" wrote

      The clearance on disc brake calipers is really tight and having a rub like that isn’t uncommon when you first set them up. The instructions that come with the Elixirs are great but here’s the jist of what you need to do:

      1. Loosen the CPS bolts just enough so the caliper is free to move side to side relative to the rotor (these are the long bolts with stacks of several washers).

      2. Spin the wheel and while it’s spinning, apply the brakes. Keeping the brake lever locked down, tighten the CPS bolts. You may need a helper but if you have long arms like me, it’s easy enough to reach.

      3. Let go of the brake lever and give the wheel a spin. In theory this will work the first time but if not, start over. If you can see which side of the caliper is dragging, nudge it in the right direction a bit while you’re tightening the bolts down.

      The process usually takes me about 3 tries to whenever I install new brakes but I’m sure it won’t take you that many attempts. 😀

      If you do suspect the rotor is bent or warped it’s easy enough to check – just take it off the wheel and lay it down on a flat surface (a table).

      I’ll give this a try tonight and let you know. Thanks!

    • #105576
      "ollysj" wrote

      Have you tried, to push back the pistons?

      +1

      In addition to everything trek7k said, you may need to reset the pistons too.

    • #105577

      ollysi and mtbgreg are right – if you (accidentally) pulled the brake lever while the wheel was off, the calipers can get locked down. Avid usually includes a couple of red plastic wedges with the brakes – use one of these to pry the calipers apart to reset the pistons.

    • #105578
      "trek7k" wrote

      ollysi and mtbgreg are right – if you (accidentally) pulled the brake lever while the wheel was off, the calipers can get locked down. Avid usually includes a couple of red plastic wedges with the brakes – use one of these to pry the calipers apart to reset the pistons.

      Hmmm, well, even though I know NOT to, I did apply one of the brakes before installation and immediately cringed. When I unpacked it all though, I found the red plastic wedges you describe and assumed that saved me. I’ll keep it in mind if your first suggestion doesn’t work. Thanks again.

    • #105579

      Yeah, if you pull the lever with the wedges in you should be ok. The calipers only get locked down when you apply the lever with nothing in between the pads.

    • #105580

      At the trailhead, while you’re getting ready to put the front wheel back on (if you have fork mount racks) some moron always walks up and says, "Hey, how do you like your hydraulic disc brakes?" <squeeze> 😏

      For this reason, I keep one of those plastic slider thingies in my camelbak toolkit.

    • #105581
      "maddslacker" wrote

      At the trailhead, while you’re getting ready to put the front wheel back on (if you have fork mount racks) some moron always walks up and says, "Hey, how do you like your hydraulic disc brakes?" <squeeze> 😏

      Ha! 😆

    • #105582
      "fleetwood" wrote

      [quote="trek7k":lm5sf42h]The clearance on disc brake calipers is really tight and having a rub like that isn’t uncommon when you first set them up. The instructions that come with the Elixirs are great but here’s the jist of what you need to do:

      1. Loosen the CPS bolts just enough so the caliper is free to move side to side relative to the rotor (these are the long bolts with stacks of several washers).

      2. Spin the wheel and while it’s spinning, apply the brakes. Keeping the brake lever locked down, tighten the CPS bolts. You may need a helper but if you have long arms like me, it’s easy enough to reach.

      3. Let go of the brake lever and give the wheel a spin. In theory this will work the first time but if not, start over. If you can see which side of the caliper is dragging, nudge it in the right direction a bit while you’re tightening the bolts down.

      The process usually takes me about 3 tries to whenever I install new brakes but I’m sure it won’t take you that many attempts. 😀

      If you do suspect the rotor is bent or warped it’s easy enough to check – just take it off the wheel and lay it down on a flat surface (a table).

      I’ll give this a try tonight and let you know. Thanks![/quote:lm5sf42h]

      I went through this process several times last night. It’s better, but still rubbing enough that I am not satisfied. I’m going to work on it some more tonight…

    • #105583

      Also… It is very important NOT to tighten those bolts too much, as you could crush the aluminum "wobblers" that help align the caliper.

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