Need some help with Trek Valencia Disc Brakes (Shimano 416)
 

Trek Valencia Disc Brakes

I recently noticed that the disc brake rotors on my 2009 Valencia bend when I apply the brakes/calipers. I have a feeling the rotor will gradually warp as I continue to use the brakes and rubbing will occur eventually. I was wondering if anybody else had the same problem with these disc brakes: according to Trek's website they are Shimano M416. Veteran LBS mechanic fiddled around with it and told me that there's nothing he can do; Shimano just makes crap disc brakes at this price point. He recommended I upgrade to Avid BB7's. I know the Valencia is by no means a high end bike w/ high end components, but I think it's a little ridiculous that a major component requires replacement within less than a year of purchase and with less than 1000 miles on it. I am waiting on Trek Customer Support to see what they can do for me, but in the meantime I would appreciate any feedback from other owners of this disc brake as well any general disc brake adjustment tips you can offer. Thanks!

The rotor should not be bending. I ran a commuter for a year with Hayes MX-2's,which are equal to or lower than those Shimanos with no issues.

Two ideas. First,maybe the rotor is warped. The wheel could've taken a shot when the bike was shipped,or something could've happened during assembly. Look straight down into the caliper and spin the wheel. If you see the rotor move from side to side,it's warped. A pair of pliers with the jaws protected by a rag or summat can be used to tweak the disc straight,just be gentle. If this isn't the issue,I'm betting the caliper was mounted wrong. It could be mounted crooked or off-center. When looking down at the caliper,the rotor should be dead center in the middle of the caliper. If closer to one side than the other,the caliper needs to be moved over.

I've amazed that some shops just don't seem to understand disc brakes. I've purchased brand new bikes from established shops that had all of the above issues. I'm betting that your issue has something to do with improper assembly or shipping.

Actually, this is incorrect. While Shimano doesn't spell it out well, SRAM does in the BB7 instructions. It's basically a 1/3-2/3 rule. If you look at step 5 here it's spelled out..

http://files.dahon.com/support/manua...es_bb5_bb7.pdf

^^^That's for the BB7,which has dual pad adjustment. If you look at the next page under BB5 adjustment,it calls for center placement. The OP's calipers are single adjust,like the BB5.

Thanks for the tip dynaryder. I am going to try to adjust them this weekend. I'm sure I'll end up making them worse and end up back here asking for help :)

I have a Valencia and the brakes rubbed when the bike was first delivered. Turns out it was inproper shop work, and I got it all fixed up and it's been working fine for quite some time now. If I have any problems I'll upgrade to a higher end brake setup.

If you look at the Shimano instructions, they expect/instruct you to adjust the outside clearance via the cable adjuster, so effectively they're adjusted both sides, similar to a BB7.

I've only had three bikes with them on, I don't know anything, that's ok :P

I wrestled with the brakes all day to no avail. One problem I found was that the inner pad on the front brake is not parallel to the rotor: the top edge of the pad (edge closest to the center of the rotor) is angled toward the rotor such that it touches the rotor before the bottom edge. To a certain extent, I think this is how the M416 is designed. The spring is on the bottom edge, so the pad clamps down like a V shaped trap instead of coming down evenly. Because the "slanted" inner pad takes up extra space, this leaves less room to adjust the outer pad, and as a result, the only way I can keep the outer pad from rubbing is to slacken the cable so much that it takes a full squeeze to apply any kind of meaningful pressure to the rotors - which, btw, still flex when the pads touch. I think at this point, I will bring it into a different shop to see if they can adjust it better than me or the first shop. Thanks again for all your help.

That doesn't sound right. Disc pads don't need to be toed in like rim pads. Could be the pad wasn't installed right. Might want to pull the pads,check inside the caliper,then reinstall.

I took the brake pad out and confirmed that this was not due to the pad not being seated correctly or some type of obstruction, but the inner caliper itself appears to be set at an angle. When I turn the small hex bolt to adjust the distance of the caliper, it is apparent that the caliper comes down at an almost 15 degree angle. I would like to find a way to adjust the inner caliper so that the inner pad is parallel to the rotor and the other pad, but it doesn't look like the caliper comes apart easily. Does anyone have experience with an issue like this? Thanks for all your help.

That just doesn't sound right. I'd take the bike back to the shop and compare it to another bike with the same brake. I can't imagine why a caliper would be designed so as to not have the pad contact the rotor flat. Maybe you just got a bad one?