Help: Can I swap freehubs between M900 and 7400?

[TwigJumper]

Greetings,

I noticed that the 8 speed freehub on a Shimano Dura Ace 7400 hub has many engagement points, around 36, and the one on my XTR M900 is about half of that. Does anyone know if these freehubs are interchangeable? I suppose I can have a crack at it, but maybe someone can save me the effort.

 

[scottproonly]

Re:

I have swapped freehubs between xtr non disc and xt disc and I found that they swapped over fine as long as I swapped the cones over as well.hope this helps

 

[scottproonly]

Re:

In case you are wondering I did this to create a lighter disc hub so I swapped the Ti axle as well.

 

[TwigJumper]

Re:

Right on. What # series hubs were they? I also thought about putting a new Shimano SLX M629 freehub (with 36pt micro ratchet engagement ) on the m900 hub but I wasn't sure if they were compatible. The new XT line of hubs with the micro ratchet engagement don't have the typical cup and cone with axle spacers like the SLX so I doubt those would work.

 

[legrandefromage]

Some of the older hubs have a raised edge on the hub body that prevents universal interchangeability

But, so do a lot of later hubs!

So that means that a lot of freewheels from the last 25 years can be swapped over. Its more common that the whole hub is cheaper to buy than just a freewheel too.

 

[one-eyed_jim]

The Dura Ace 7400 series hubs used a unique interface between the hub shell and freehub body that isn't compatible with any other hubs. See the diagram here:

http://dt6110.web.fc2.com/parts/7400/FH-7403GT.jpg

Newer XT hubs use a fat aluminium axle that requires a larger diameter freehub body interface, so those aren't compatible with steel-axled hubs either.

The FH-M629 seems to use a standard steel axle and the conventional splined freehub body interface, so I'd say there's a good chance it would fit an M900 hub.

 

[TwigJumper]

Re:

Thanks for all the input!

I took a freehub off of an SLX M675 hub.

It worked! Although, the bottom of the SLX freehub doesn't sit completely flush on the base of the XTR M900 hub since the design is a bit different. I kept the M900 axle on there. I also had to adjust my rear brake a bit.

Pictures and after-ride report to come.