I seem to have a problem with the aforementioned item. The problem is with the front hub. It is new, maybe a dozen rides old. It was fine at first, then I noticed the rotor rubbing on the pads. I thought the disc was bent, so changed it, but he problem seems to be with the hub.
The new rotor has the same “warp” so does another known good one when fitted to this hub.
It is a DT Swiss 240.
Are these known for problems? Am I missing something? How could that happen?

Dumb question. You ruled out the pad / caliber alignment?

Yep, spent ages trying to align the caliper, tried bleeding them (Sram Guide). Taken the rotor off and carefully inspected the flange and cleaned it, can’t see or feel any burs or high spots on the hub or the discs.
I think I have proved the problem by putting another wheel in, spin the wheel, disc runs true. Swap the rotor and put it on the dt 240s hub. Spin the wheel….disc appears bent, too out of true to adjust the caliper so that it doesn’t rub.

Just put some new 240’s on my bike a month back and they’re spot on, I’d ask the shop you bought them from to have a look.

Got a few 240s – both centre lock and 6 bolt and all are bang on.

As above, I’d return to retailer for inspection.

Ahh yes.. that might be a problem. I bought a set of complete wheels from a certain well known supplier of carbon rims. Based in China.
They have been a disaster. The back wheel fell apart after a week. The dt swiss alloy nipples had their heads pulled off.
Now the hubs appear to be made of lead.

Fakes???

That’s what I am starting to think, they seem very good quality. The finish is very good. They look real enough. I have another set of wheels from the same place and they have been faultless over a couple of years, they have Hope hubs though.
I cant imagine what force could cause a hub to deform enough to make the bolt holes out of true, but I cant see any other cause for it.
I will have another look tomorrow.

Definitely sounds fishy, there are plenty of fake 240’s about being sold from the Far East or Eastern Europe.

Sorry to say but it sounds like you may have been had.

I wonder if there is some way of identifying the genuine item. I want to be careful not go slandering a companies good name without being sure of the facts.
I would be very surprised if they are not the real thing.

Ask DT or Madison (the UK importer)?

Good idea, I will give that a try.

Does it always rub in the same place, or does it seem to move around? If the latter, then it could be a collapsed / faulty bearing.

there are plenty of fake 240’s about being sold from the Far East or Eastern Europe.

Are there?

The bearing runs smooth as silk, there is no play laterally at the rim, and the rim runs completely true.
Its a mystery.

TBH with all the metal and flex between the hub and the braking surface I’d be pretty surprised if a warp on the face unless it was massive would translate to a warp in the braking surface. So I guess you’d be looking at it being squint rather than uneven. Though, even if were a fake hub (haven’t heard of fake DTs, but maybe) it’d probably be harder to machine it uneven or squint than it would be to do it right.

Simpler solution is- rotors bend easily, truing them is normal. New rotors are bent more often than not. Its the more likely culprit imo.

You can easily check the for runout though- put the hub in the frame with no disc in, get something (allen key or similiar), spin wheel, put allen key on fork leg, move it closer to the disc face til it touches. Same idea as truing a wheel. You’ll soon see if it has high or low spots

Thanks for that, will try it tomorrow, I can’t really see LB using snide hubs. The rotor would need a lot of trueing though. I can usually straighten them by hand, but this is a really pronounced “kink”

Place the rotor on a glass mirror to check for trueness and also make 100% sure that the hub is fully seated in the dropouts when you tighten the skewer

Do you have a second bike to drop the wheel in and try out? Very odd to have been okay and then not be and everything is the same. Rotor would warp before the hub.

Only other things I can think of are possibly a threaded bolt so it isn’t holding the disk flat or something up with the dropout / hub interface. Maybe the adaptor isn’t completely flush against the bearing or the bearing is failing.

I’d try a few more of the above suggestions then take it to my lbs….

Thanks all, I will try the mirror and other ideas and report back.

What forks are you running?
A mate of mine has bent two sets of qr sids, one eventually snapped at the crown.
The first sign was the wheel alignment and rotor rubbing.

Dont need to do all that much to prove hub or rotor. Mark on the rotor where the wobble is (on the arm nearest with a marker) Take your rotor off, turn it round so the outside face is inwards now AND rotate it 180 degrees so you are bolting it to the opposite holes too (so its technically on the wrong way and opposite bolt holes). Repeat. If the wobble is now the other way and at the same place on the rotor, its the rotor. If its still wobbling the same way, and the wobble is now on the opposite side of the rotor, its the hub.

Maybe one of the rotor mount’s on the hub is thicker\thinner than the others.

I am still none the wiser, I have tried all above suggestions. The forks are new Pikes by the way. The bike is only a few weeks old, but I didn’t like the OEM wheels, hence the “upgrade”.
I cannot identify one specific wobble. The disc just seems to gyrate when on that hub. Reversing it doesn’t seem to make it clearer. I have tried the problem wheel in another bike, the problem is in that wheel.
I have checked that the bolts are not bottoming out in the holes.
The flange for the hub looks completely true when spun in bike and checked using the allen key test. No high or low spots that I can see.
I have ordered a new sram centreline rotor, I have been using KCNC and I don’t think they work very well with Guide calipers.
Maybe I just have a pile of bent rotors….but they work ok on the original wheel….