Shimano freehub bodies.

[blackbike]

I have a few rear wheels and old Shimano rear hubs from the 90s through to about 2006 and I've swapped and changed freehubs between them as necessary to avoid buying a new freehub. They all seem to have the same fitting which looks a bit like this

https://www.winstanleysbikes.co.uk/prod ... Gwod-N8DDA

The hubs are of various types - Alivio, 105, STX, Tiagra, Sora etc, XT.

Now I need a new 8 speed freehub and some of them look different now so I'm a bit cautious about ordering.

Is there a basic freehub which fits all older hubs or have I just been lucky that all the wheels I have take the same freewheel?

Anyone know anything about them?

[Brucey]

https://forum.cyclinguk.org/viewtopic.php?f=5&t=112398

shows what you are up against. There are numerous differences in the RH dustcap and seal arrangements. However provided you are happy to fiddle with those parts many alternative freehub bodies can be made to work OK.

FWIW there are several types of hub that don't use the original interface to the hubshell;

- FH-RMxx use one of two different splines that are not compatible with other hubs.

- recent LX versions use a different hollow bolt and a recessed fitting in the freehub body for the bolt head.

- Dura-Ace freehub bodies have used several different arrangements, few of which are like other shimano models

- Any freehub that uses a larger diameter axle (e.g. current XT, SLX etc) also uses a different pattern freehub body.

https://forum.cyclinguk.org/viewtopic.php?f=5&t=96294 has a photo showing some of the variants.

If you use the wayback machine to access the shimano USA website (as it was about four years ago) there was a page on that which listed some useful generic technical pdfs, including one that listed freehub body part numbers and those which interchanged.

At present SJS appear to stock the widest range of freehub bodies; the photographs show the variety of different RH seal arrangements. The EV techdocs for individual hubs usually show the type of spline interface for any given freehub too.

hth

cheers

[blackbike]

Thanks for the info.

Those previous threads are very short, which makes me suspect that not many people have much knowledge of this subject, and why my new thread hasn't had many replies.

Even Sheldon Brown doesn't have much to say except that that Shimano freehubs are usually interchangeable - except when they aren't.

I might need to make a very rare visit to a local bike shop to make sure I get the right thing as it is impossible to be sure via mal order.

[Brucey]

the LBS will be able to help if they have stock of freehubs. IME this is unusual; they order them in as required.

If you have a particular model of hub that you need a freehub body for, it is easy enough to find out the correct part number and to order that, or just to look at the pictures you will find online for that model.

There is plenty of knowledge out there, but your question is very vague; there are numerous (different) versions of every hub type you mention.

cheers

[recordacefromnew]

Thanks for the info.

Those previous threads are very short, which makes me suspect that not many people have much knowledge of this subject, and why my new thread hasn't had many replies.

Even Sheldon Brown doesn't have much to say except that that Shimano freehubs are usually interchangeable - except when they aren't.

I might need to make a very rare visit to a local bike shop to make sure I get the right thing as it is impossible to be sure via mal order.

Chance is, if you have a somewhat random collection of wheels over the years and they have interchangeable Shimano freehubs, then the freehubs would be the 10 spline ones (i.e. same as the one in your link), and the axles M10.

But as Brucey indicated, the difficult issue is not whether the freehub is compatible at the interface with the hub-shell, but whether you can find one easily that happens to deliver a good weather/dust seal, without clash, with your existing drive side cone/seal/dustcap arrangement on your axle; yet we have not even been given the faintest clue what you have there, when asked to recommend a suitable freehub...

A solution to circumvent that problem, and it is essentially better than free if you are happy with just contact seals*, is once you have established that your freehub / hub shell interface is 10 spline, you can follow Sheldon's advice and just go ahead and buy any one of their hubs with the 10 spline interface, e.g. FH-M475 (135mm OLN). It is free because some of these hubs should only cost pennies more than a new freehub from your LBS, if not cheaper. However now not only do you have a new compatible freehub, you also have new and compatible drive side cone/seal, axle (if you pick a hub with the same OLN), two sets of 9 new bearings, and a new non-drive side cone which might come useful on some hub some day.

* because unfortunately, imho Shimano has downgraded the design of their recent low/mid level hubs, only having simple contact seals at the drive side for nearly all of them if not all of them, while not so long ago most had a labyrinth-like arrangement, as can be seen in the EV of e.g. the Alivio FH-MC18.

[blackbike]

Thanks for the info.

Those previous threads are very short, which makes me suspect that not many people have much knowledge of this subject, and why my new thread hasn't had many replies.

Even Sheldon Brown doesn't have much to say except that that Shimano freehubs are usually interchangeable - except when they aren't.

I might need to make a very rare visit to a local bike shop to make sure I get the right thing as it is impossible to be sure via mal order.

Chance is, if you have a somewhat random collection of wheels over the years and they have interchangeable Shimano freehubs, then the freehubs would be the 10 spline ones (i.e. same as the one in your link), and the axles M10.

But as Brucey indicated, the difficult issue is not whether the freehub is compatible at the interface with the hub-shell, but whether you can find one easily that happens to deliver a good weather/dust seal, without clash, with your existing drive side cone/seal/dustcap arrangement on your axle; yet we have not even been given the faintest clue what you have there, when asked to recommend a suitable freehub...

A solution to circumvent that problem, and it is essentially better than free if you are happy with just contact seals*, is once you have established that your freehub / hub shell interface is 10 spline, you can follow Sheldon's advice and just go ahead and buy any one of their hubs with the 10 spline interface, e.g. FH-M475 (135mm OLN). It is free because some of these hubs should only cost pennies more than a new freehub from your LBS, if not cheaper. However now not only do you have a new compatible freehub, you also have new and compatible drive side cone/seal, axle (if you pick a hub with the same OLN), two sets of 9 new bearings, and a new non-drive side cone which might come useful on some hub some day.

* because unfortunately, imho Shimano has downgraded the design of their recent low/mid level hubs, only having simple contact seals at the drive side for nearly all of them if not all of them, while not so long ago most had a labyrinth-like arrangement, as can be seen in the EV of e.g. the Alivio FH-MC18.

Your reply is helpful because I am now getting the impression from you, Sheldon Brown and Brucey that until a few years ago most Shimano freehubs were of the same basic design and that they only differ in minor detail such as the dust cover, and that a bodge is usually possible to keep the wheel on the road for another year or two. That is what I have already found when swapping freehubs around.

I asked the question because I was recently given three buckled and useless back wheels by my nephew as I said I'd be able to use the Shimano freehubs, but when I took them off they were a completely different design at the interface with the hub. It seems that more recent low-end Shimano hubs have been redesigned and are not compatible with older ones.

The idea of buying hubs rather than freehubs did occur to me, and that's what I'll probably do. Freehubs seem overpriced to me when hubs only cost a bit more, but I suppose only a small minority of cyclists ever buy them so demand is low.

[Brucey]

..... It seems that more recent low-end Shimano hubs have been redesigned and are not compatible with older ones...

I would expect that to be because the hubs in question are FH-RM** ones as indicated in my earlier post.

cheers

[mattsccm]

May not be totally helpful but look in skips. I break up every wheel I find and have never found a Shimano free hub that won't fit my selection of wheels. Of, course Durace and new stuff never appears in the places I find wheels so that isn't an issue. A big box of all the discarded seals etc will provide all you need.

[Brucey]

FWIW looking at this page

https://www.sjscycles.co.uk/shimano-freehub-bodies/?page=2

will give you an insight into how many different shimano freehub bodies there really are.

BTW I thought all the FH-RM** series had a different interface design (one of two types) but it seems that there may be an exception; FH-RM40 freehub body appears to have the same 'old type' interface design.

cheers