I had a warped rotor that I finally got around to replacing. But the new one I’ve put on is still warped…

So I’m assuming that this new rotor isn’t actually warped, but that something else is going on. I’m not sure what though – could the hub (6-bolt fitting) somehow be the problem? Or could it even be the forks?

I’m a bit confused as the hub bearings seem good and the forks are straight, undamaged etc.

either or both could be bent. stick it on a kitchen work surface and see if there are any high spots. straighten by tweaking it with an adjustable.
‘warped’ rotors usually refer to the idea that they can change shape after heavy breaking due to heat, BTW. typically what happens is you get a lump of hot pad deposited on to the surface. the disc doesn’t alter shape at all.

calliper on straight?

Rotors are so easily bent at they will deform with the smallest knock that could be picked up anywhere. Consequently they can be bent back with a finger. Just spin the wheel, watch for where it rubs then move that bit away from the calliper and tweak it.

As del says – take them off and put on flat surface to see if bend is ‘in’ the rotor.

If not, could you have a bolt hole out of line or wonky? Flaky paint or six mounting surfaces not flat to each other.

I had a similar problem. When I check the rotor it was flat so I clocked the hub face and it was reading as warped there were burs so it must of been on the limit of tolerance. At the time the most cost effective solution was a new wheel. I think there are hub facing tools that could sort it.

So is the brake rubbing which makes you think it’s warped? First up, align the calliper and see if you can get it to spin free. I’ve seen a number of people end up replacing pads and rotors when simply the calliper was misaligned. Also, there’s a chance the rotor is the wrong size or the calliper has the wrong adapter or needs one.

If all else fails, pliers are your friend 😉

How are you tightening the bolts down. What order?

I was gonna say bolt order too. Opposites, not one after another….

Yeah, guy in our club always had warped rotors until we realised what he was doing. Turning the first couple of threads on each bolt into the hub, then tightening up to torque. Amazing how much wobble you can put in doing that.

Check flatness on a mirror or other glass surface.
I have managed to bend a disc removing it from packaging, but I am an idiot.

Thanks for all the replies everyone.

So, it’s definitely not a caliper misalignment or an incorrect mount – the rotor is a few mm out of true so it’s just not possible to stop the pads rubbing. I’m also fairly certain the rotor can’t have been bent before I installed it as it arrived in an oversized ChainReaction box.

I reckon the bolt hole surfaces could be a problem, though I did clean and inspect them and they seemed OK.

But, I may well have tightened the bolts in the wrong order… That is some advice I’ve never come across before so thanks 🙂

Is the rotor rubbing all the way round?
Is the rotor ‘catchimg’ once or more on its way round?

Don not assume a new rotor is flat and true…

Brake pistons imbalanced?

http://www.pinkbike.com/news/tech-spotlight-brake-caliper-piston-service-assessment-2014.html

Pushed pistons back at least? Or maybe pistons need a service.

New rotors are frequently bent, regardless of packaging, it’s pretty normal to spent a little time tweaking them true. As long as they’re not creased, rotors can usually be straightened easily.

With IS brakes there’s an easy trick you can use. Undo a bolt at one end of the brake adaptor, then swing the adaptor round so that the other bolt hole is over the brake track. Then, thread the bolt back through til it’s almost touching the disc (over the most solid bit you can find). Spin wheel, tighten bolt, you have a very accurate runout gauge.

I haven’t read all the above.

I had something similar yonks ago, the mechanic had cocked up fitting the disk. The steel edge by the bolt had cut and pushed a thing curl of ally swarf into the inside corner of the mounting thingy. So the rotor curved out at that point. Fifteen seconds with a needle file sorted it. YMMV.