Mountain Bike Reviews Forum banner

Can an out of true rim cause rotor alignment issues?

16K views 51 replies 12 participants last post by  meltingfeather 
#1 ·
I received a replacement rotor (front wheel) from Avid as it appeared to be warped. I put the new rotor on, which is mounted on an aftermarket set of Stan's Crest ZTR rims/hubs w/ the stock Avid Elixir 3's, and it also appeared warped. I tried adjusting it to no end, and couldn't get it in any position that it wouldn't rub on the pads.

For an experiment, I put the rotor on the stock front wheel and it runs nearly true and the caliper has no rub on the pads.

What is going on here? Is the wheel out of true somehow (or is it the hub) that would cause this? Thanks for any insight.
 
#41 ·
No way in hell I'm warping a brand new, perfectly good (and not cheap) rotor to make it work. That's like treating the symptoms and not the cause.

If this doesn't fix the problem, then I'll sell off what I can of the Stan's wheelset and use the Mavic wheelset off my FS bike since I don't really ride it during the wet winter/spring months and be done with it...
 
#50 · (Edited)
Very few things I've bought were perfect. Most needed something. Fork needs levels checked when new. Brand new replacement electric motors need oil, most are near dry. I even had to "adjust" a brand new toaster..had to cut off some air inlets at the bottom so it would run hotter. Ever bought a new car?

Rotor truing is standard procedure.
You need at least 2 bikes like me. One to make perfect and one to ride.

I do feel your pain AK47..I do.



Just thinking..Hub face has .001in run-out. From my puter bolt circle is about 2"...1" radius..Project that out to a 6" or 8" disk..3-4 radius..quickly is .004 at the caliper. With the close pad clearance ,004 minus pad clearance, leaves little room without rubbing at least some of the time. You probably know .001in is not much. Out of aprox 8 sets of disks and hubs I've owned all needed tweeking for a no rub ride. Have at it..
 
#2 ·
Sounds like the hub is warped. The rim being out of true would not directly affect the rotor. However, if the rim is damaged from a wreck, it is possible the hub was also damaged or bent at the same time. Not the end of the world though. As long as there are no cracks, it is alright.

I would have the wheel spokes tensioned and the rim trued first. Then remount the rotor. Recheck for true. You may have to true the rotor after it is mounted to compensate for the hub. There are tools for this, and some people do it with an adjustable wrench. You should be fine if you can get it relatively true.
 
#3 ·
Nothing to do with the RIM, your HUB flange needs to be faced, it is obviously not square. Check and see if your local shop has the tool, if not it's not cheap sadly, HOPE makes one, but about $150 IIRC.
 
#5 ·
Another thought on this...Did you realign the caliper when you swapped wheels? If you didn't it could just be as simple as your old stock hub being slightly narrower or wider than the Stans and you need to realign the caliper to the new hubs. Hardly any rotors come 100% true, but they definitely shouldn't have a seriously noticeable wobble when new. Try installing the Stans wheels again and centering the caliper or have the shop do it.

Sorry, was thinking of the one for doing the fork tabs when IS was the standard.
 
#10 ·
1niceride

Mark the rotor in relation to the hub or rim. Notice and mark hi or lo point on rotor. Remount rotor 180 deg. If hi or lo mark followed the rotor, its a bent rotor. If mark stayed with the rim, its the hub. Easy peasy.
:thumbsup:

Is the new rotor thickness exact same width as old one ? I had this problem and was going crazy trying to figure it out - the supposed replacement was about 1 or 2 mm thicker so I pitched it ......... made a good frisbee !
 
#14 ·
Perplexed beyond belief...

I really appreciate all the ideas, but after my last attempt at a fix, I am really at my wits end...

I invested $350 on a new set of Shimano SLX brakes (IceTech) w/ the IceTech rotors. And sure enough, the brand new, high end rotor wobbles as well on the ZTR front wheel. I was thinking it also might be a bent skewer (9mm), but after reading above that doesn't sound like the culprit (but I'm going to give it a try tomorrow anyway after a good night sleep just to eliminate that possibility).

Process of elimination would dictate it has to either be the skewer or a warped hub since the rotor runs true on the stock wheelset. I sent a message to Stan's about it but then never responded.

Added to this frustration, I can't get the front caliper to center without rubbing!! I was really hoping the Shimano's would mount up trouble free after all the positive reviews I read about them before buying. I know hydros have a better feel and look way better than mech brakes, but damn I don't have these issues with simple mech's like BB7's.

:confused: :madman: :confused:
 
#15 · (Edited)
I really appreciate all the ideas, but after my last attempt at a fix, I am really at my wits end...

I invested $350 on a new set of Shimano SLX brakes (IceTech) w/ the IceTech rotors. And sure enough, the brand new, high end rotor wobbles as well on the ZTR front wheel. I was thinking it also might be a bent skewer (9mm), but after reading above that doesn't sound like the culprit (but I'm going to give it a try tomorrow anyway after a good night sleep just to eliminate that possibility).

Process of elimination would dictate it has to either be the skewer or a warped hub since the rotor runs true on the stock wheelset. I sent a message to Stan's about it but then never responded.

Added to this frustration, I can't get the front caliper to center without rubbing!! I was really hoping the Shimano's would mount up trouble free after all the positive reviews I read about them before buying. I know hydros have a better feel and look way better than mech brakes, but damn I don't have these issues with simple mech's like BB7's.

:confused: :madman: :confused:
Centering disc brake calipers can be a form of art, especially if the brake you are trying to adjust has cps washers(yes i realize that Shimano doesn't have cps). Its not just you, many others had trouble with adjusting disc brakes.

It may be time to take the hit to your pride and take it to the pro's.

EDIT:

It could even be a problem with the brakes them-selfs... On some avid brakes, I have seen them come with too much fluid in them from the factory, or some other sort of problem many times... In short causing the gap between the rotor and the pads to be too small for proper adjustment. H*ll the mounts on your frame or fork could have been machined at an angle causing the caliper to sit at an angle (in which case they would need to be faced with a special tool).
 
#17 ·
this may be a shot in the dark, but are you using a torque wrench to tighten the rotor bolts? (assuming you are using a 6 bolt design).

If not, you may be tightening one bolt more than the others, which could be causing your 'warping'. as you switch the rotors between hubs, you may feel like you are chasing a warp that isn't really there.

I would recommend torquing the bolts, and then trying to true the rotor in a truing stand using a machinist's dial. If that doesn't fix it, then I'm guessing your hub is somehow warped.
 
#19 ·
Uncle!

Yep, using a torque wrench for sure. I tried a brand new skewer and that wasn't it. It's some issue with the hub flanges or bearings or both. Definitely a bummer as the Crest ZTR wheelset is 2lbs lighter than the stock wheelset. :(

I give up and am heading to the bike medic tomorrow with both front wheels in hand...
 
#20 ·
Yep, using a torque wrench for sure. I tried a brand new skewer and that wasn't it. It's some issue with the hub flanges or bearings or both. Definitely a bummer as the Crest ZTR wheelset is 2lbs lighter than the stock wheelset. :(

I give up and am heading to the bike medic tomorrow with both front wheels in hand...
Hate to sound like a broken record, but why are you ignoring the relatively easy out of truing the rotor? It takes 5 minutes and you'd be done. :eek:ut:
 
#39 ·
Hope you are right. LBS said after pulling apart the front hub, nothing was screaming at them in terms of critical wear. The bearings do indeed show wear, but nothing critical. They are ordering new bearings and end caps to determine if this is the issue, and at only $35 for the investment, I'm willing to experiment. I should know in about 1 week.
 
#40 ·
Has anyone ever checked a new stem for squareness and round holes? Or a crooked frame? Wheel with wrong offset? If you are lookin for perfect, good luck. A lot of this stuff is a do it yourself kit.

Warp the rotor to fit the hub and go riding. You'll change out the hub or wheel only to find the same or worse results. If only it had a batch number..
 
#43 ·
A lot of times truing a rotor is a standard procedure. They are very rarely straight from the factory. Nor do they stay straight under normal riding. If you do decided to go the easy route and true it, you can always true it back when what ever is going on with the hub get's corrected.

Have you tried mounting the rotor in different positioning on the hub to see how it affects the problem? Does the wobble in the rotor stay the same relative to the hub? If the end caps and bearings you've ordered don't fix the problem I would just replace the hub. It's not worth trying to machine or file it down. Especially if it's under warranty. FWIW when you get Stans on the phone they are probably going to just suggest that you true the rotor. Like M-feather said, there really isn't a compromise with this solution.

FWIW, I know the C-dale/CX world team keeps their rotors matted to a specific wheel and keeps them clocked to a specific orientation when they get removed for travel. They do this because even their top end race quality parts still have quirks on setup. On the occasion their system breaks down, they just re-true the rotor to the new position.
 
#44 ·
Curious AK, you haven't mentioned if you've given Stans a call about this, I'd expect these wheels are new and they'd deal with it under warranty or are the wheels 2nd hand? Customs suggestion of rotating the rotor would for sure tell you if it is only the ub or a combination of hub and rotor.

As to 1niceride, yes, most of my stems come square, but I did buy a couple OEM Cdale stems and they were not, casting had more material on one side of the clamping area than the other, faceplate was alright, so I filled/sanded down the high side to square things up. I've also filed down forks tabs to square them up on an old IS tabbed fork, it's actually something that was done a lot, Hope has a sweet tool for it.
 
#45 ·
Curious AK, you haven't mentioned if you've given Stans a call about this, I'd expect these wheels are new and they'd deal with it under warranty or are the wheels 2nd hand?
I purchased the wheelset brand new about 1.5 years ago. Stan's only has a 1 year warranty, but if the new end caps/bearing doesn't solve the problem I will certainly be giving them a call to inquire. Other than this issue, they have been great wheels. If I need to, hopefully an LBS would be willing to remove the ZTR front hub and re-use the rim with a new hub...
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top