G1800 rear hub movement

I noticed a bit of a knock when sat on my gravel bike and rocking the bike which I occasionally do to check that the  headset hasn’t loosened off  I checked & re-tensioned the headset but the knock still remained – but only, it turns out, when actually seated. It turns out it’s the rear hub of the G1800 wheels (370, 3 pawl).

If I put the bike in the rack and apply the rear brake, I can hold the tyre and rotate the wheel back and forth very slightly. It’s only about 1mm of movement but accounts for the odd knocking. I can see the hub move slightly between the cassette & brake mount (the rotor & cassette don’t seem to move).

I’m not sure if this is meant to happen (is it related to the hub’s pick up which I gather is slower than the ratchet hubs DT Swiss do) or do I have any issue. If it is a problem do you have any suggestions.

The cassette, rotor & thru-axel were all correctly torqued.

I’ve emailed DT Swiss support at Madison but I thought I’d ask here too.

It’s not the pads moving in the caliper? That’s pretty common and not sure how the freehub would be the root cause of what you described.

Sounds like pads moving to me all. Watch the top of the caliper, you may be able to see them move back and forth.

or a centre lock disc moving on the splines?  there is always some play in a cerntrelock setup usually disguised by the tightness of the fixings

Not when torqued to spec.

I’ll have a look, thanks.

It sounds like this though – https://www.reddit.com/r/bikewrench/comments/syqshp/playmovement_between_rotor_and_hub_dt_g1800/

Although mine are Centerlock rotors. I’ll double check the rotor lockring too.

Not when torqued to spec.

the freeplay is still there – its just the tightness of the lockring makes it less likely to be noticed / an issue.  centrelock has to have that freeplay as its a sliding fit on splines.

Not when tightened to 40Nm – same as a cassette on a splined free hub – movement is there until preload is applied with locking.

By the same argument a 6-bolt rotor has movement on the 6 mounting bolts – until preload is applied by torquing the bolts to spec.

Which cassette are you running?

The G 1800’s come with a road spaced freehub, if you’re running a MTB spaced cassette you need to put a 1.85mm spacer behind it.

Without the spacer the cassette will ‘clunk’ even if it’s torqued up.

Thanks. It’s a 10 speed Deore on a road HG freehub but I have DT Swiss’s own spacer in place; all up to torque & no play.

When I’m back home I’ll double check the rotor lockring and go from there

The Fulcrum RacingSport77DB rear that came with my Cube Attain GTC periodically loosens the endcaps, allowing the hub/cassette to move a bit side to side, gets obvious when it needs tightening urgently as sprocket changes don’t shift nicely.

All resolved 👍

It was a rather loose lockring on the rotor. I’m not sure how it happened as I’m pretty sure I did the front & rear rotors at the same time with the same torque wrench.