My new YT Decoy came with a DT SWISS H 1700 SPLINE Hybrid wheelset. Less than 150km in, the microspline freehub started spinning in both direction ancc D.C. making a horrible noise!

The freehub is a star ratchet-type, the same level as the 350 series hubs. I have rear hubs with 350 intervals and a 240 and have never had this issue.

I am familiar with the internals and servicing of DT’s ratchet hubs, however when I have taken it apart – it looks completely normal…

I have no clue what’s causing the issue. So has anyone else got any ideas?

Springs in the wrong way round? They should be conical with the narrower ends up against the ratches.

Too much grease? Stopping the ratchets from meshing fully?

They were installed correctly (First thing I checked 😉) and the hub had the light greasing it should have had.

Never had or heard of this issue without damaged ratchets or incorrect assembly.

Is the washer/spacer that goes over the axle and sis inside the ractchets there?

It’s often missed out in services and can lead to you ending up with a geared fixie but oin rare occasioms it can produce the effect you’re describing.

Tricky to speculate more without having the wheel in front of me unfortunately.

Yep it’s there. Thanks for responding – much appreciated! 👍🏼👍🏼👍🏼

Not damaged the recess grooves the ratchets locate into the hub and freehub ?

Not damaged the recess grooves the ratchets locate into the hub and freehub

Looks fine to my visual inspection. Hopefully that couldn’t happen within 150km from new…

I’ve never had this issue before – using DT hubs and DT hub internals for 13+ years.

Strip it and rebuild it, the only things that could cause this issue is that spacer being incorrectly inserted or missing, the springs being missing or wrong way round, or that the ratchet outer rings inside the hub or freehub is damaged.

Have you tried another of your freehubs to see if it’s a problem there, can’t see it being the one inside the hub, that’s left hand thread and a nightmare to get out at the best of times, let alone slipping without it!

My guess is that if you try another freehub it’ll work, may require a strip down of the freehub?

I am going to try another freehub to see if that’s the issue. The current hub is definitely all present and assembled correctly though. I did wonder if there was something specific about the Shimano microspline-type freehub that had some additional component.

So, I replaced the freehub ratchets and springs with one from a 13 year old DT Swiss 240 hub. Kept the spacer from the new hub however.

Guess what?

It works! Faultlessly – in the stand and fully installed on the bike and ridden.

Result! Email to YT to raise the issue now!

Have you shredded the teeth profiles on the Yt supplied set?

Have you shredded the teeth profiles on the Yt supplied set?

I looked into the sump of my previously clean degreasing tray and it looks very much like tiny bits of swarf…

The freehub ratchets or factory assembly must have been faulty. I can’t have caused this issue in less than 150km of pretty tame and dry riding.

Is your rear axle a stealth type?

Is your rear axle a stealth type

I don’t think so, it’s a DT thru-axle with the normal DT spin-type lever.

I have an idea, did you buy the microspline conversion kit with an end cap or just the freewheel body?

If you’ve used a non-microspline end cap it may not be pushing the freehub firmly enough into the hub and that could explain the lack on engagement.

The proper microspline end caps will have text etched on them, no text means its almost certanly for Shimano HG and that could be your problem.

In 16 years of riding DT hubs, I’ve only ever damaged star ratchet teeth twice (36t). Once was riding with a rather loose axle, under my “immense power” cassette must’ve shifted outboard and I ate the tip of the teeth off. Even when fully tightened again it would still skip under power.
The other time was by neglecting to use a chainwhip when tightening a garbaruk cassette… Stars skipped and chewed the edge off a couple. Removed the tiny pieces and deburred, cleaned and regreased and that set has been fine ever since.
I pickup used hubs when I see them cheap and every now and again there’ll be an abused set with rounded teeth on just one half of a star set.
If you’ve sheared the mating faces, you’ve essentially created a star ratchet set that disengages in both directions.

I have an idea, did you buy the microspline conversion kit with an end cap or just the freewheel body?

If you’ve used a non-microspline end cap it may not be pushing the freehub firmly enough into the hub and that could explain the lack on engagement.

Wheelset came as standard on my new bike about 3 weeks ago. Was always microspline 12 spd.

In 16 years of riding DT hubs, I’ve only ever damaged star ratchet teeth twice (36t). Once was riding with a rather loose axle, under my “immense power” cassette must’ve shifted outboard and I ate the tip of the teeth off. Even when fully tightened again it would still skip under power.
The other time was by neglecting to use a chainwhip when tightening a garbaruk cassette… Stars skipped and chewed the edge off a couple. Removed the tiny pieces and deburred, cleaned and regreased and that set has been fine ever since.
I pickup used hubs when I see them cheap and every now and again there’ll be an abused set with rounded teeth on just one half of a star set.
If you’ve sheared the mating faces, you’ve essentially created a star ratchet set that disengages in both directions.

I can see how that could happen. I have only taken my rear wheel off twice for car transport and I am really careful about axle tightness – a bit anal about it really… In this case, I don’t think it’s user error.