Free hub body problems - Help.

Can anyone tell me the difference between these two free hub bodies ?
Can anyone confirm that the 9 bearings are placed in the (apparent) race in the in the notched body on the right?

I’m having a spot of bother
1) the free hub on the left was the original - I bought the one in the right to replace it

2) tightening the cone sends it too far in so that I can’t use the cone wrench

3) Simply turning the axle from the non drive side tightens or loosens the cone without me even touching the cone -

4) there weren’t any spacers - initially the locknut was secured fast - probably locktite’d away from the cone -

5) setting cone just right (as explained in every video and guide) and then tightening the lock nut against the cone is a pointless Exercise as the axle turning then tightens it even more - and then point 3. Above comes into force and they both make their way in-wards to tighten horribly jamming the wheel

Admittedly the bearings in the non drive side are rough as a ninja and I’ve ordered a replacement 61901RS cartridge bearing. So it may be friction which is doing this - or it may be that I’ve erred and am using the wrong grease - thick blue parktool stuff rather than the butter scotch type.
Would spacers help? Or the apparent original locktite locknut method?
Or Is the hub is basically screwed?

Loving them carbon frm hubs!!!

I’m not! Nothing but grief!
They were rough when I got them - the free hub body was making clicking sounds And the off side cartridge bearing sounds rough -
Rideable but as I’ve serviced/replaced hubs before I didn’t think it would be this difficult and irritating -

Sorry I can't offer any real help. I'm terrible with wheels, hubs and bearings

when rebuilding rear hubs you should always lock the drive side cone/spacer/cone lock nut before you put the axle in the hub, then do all adjustment on the non drive side.

those are 2 slightly different freehub bodies though, this means that the cones/spacing may differ.

if you have the part codes of the freehub bodies then i may be able to work out the correct spacing for you by using the SI.Shimano website

and yes 9 x 1/4 inch bearings.

Thanks for this
I bought this one (the notched one)
M750/756...


So I’d set the drive side first on the axle - then insert axle - then adjust the off side?

that is an odd description, i'm sure the RM30 design is quite different so to see that part code mixed in is surprising, i'll have a look though tomorrow when i'm back at work

Hmm I have come across almost the same woes on a mixed bearing hub like this. Firstly you asked the difference between the two freehubs. They are indeed different, with the replacement having a deeper race, which requires a different axle cone. You need to get the non-drive side with the replaceable race sorted, with the right spacing, and then work on the drive side.

The original freehub is the standard Deore-level HG50 freehub - nice unit, still relatively easy to get. To use the original cone you really do need the original pattern freehub.

Once you have got the non-drive side sorted, if you have a soft-jaw vice, or make up so wooden clamps, you clamp the axle on the non-drive side, so the wheel is facing upwards, and then you can set the cone and lock nut on the drive side, you can adjust very precisely when you clamp it this way.

Thanks guys and thanks for the advice and the model number of the original which I think I shall get now - as too much flaffing - I assume I’ll need 9 bearings too

Oh....should have said that sometimes you can JUST get a campag thin cone spanner and a normal spanner onto the drive side cone and nut but sometimes you can’t, and you need to have that access on this kind of hub, since if I have read it right, and this one is the same kind of PITA hub that I have, the non-drive side is just set, you need to replace the cartridge bearing and then knock the cartridge onto the axle, then knock the bearing containing the bearing in. That means all adjustment has to be done at the drive side. Which is a pain.