heygregor

I have a Shimano 600 Tri-Color (6400) group on my 1989 Fuso. It's 7-speed Uniglide. Hyperglide would seem to be a desirable upgrade. Between RJ's uniglide-hyperglide freehub conversion video and Sheldon's pages, it looks like this will work. I'm not sure about the shifter and the chain, though. Will my uniglide chain work on the hyperglide cogs and do the two cassettes have the same cog spacing (necessary for matcing to the shifter)? Thanks in advance for any personal experience or reference links.

JohnDThompson 

In principle, your current 7-speed chain will work with a 7-speed Hyperglide cluster. In practice, a worn chain may not mesh smoothly with a new cluster, particularly on the smaller sprockets. You have little to lose by trying your current chain on the new cluster, but be prepared to have to purchase a new chain in the event it does not work with the old chain.

rccardr 

Shifter will work just fine, spacing is the same. Good point about the possibly worn chain, John.
If you do need to replace, any brand of 6-7-8 speed chain will work, my preference is SRAM but KMC is OK too.

70sSanO

Are you planning on swapping out the UG freehub body with a UG/HG or modifying the HG splines?

I am running a UG 13t threaded cog with a HG cassette. I don’t think it is quite as good as all HG, but it works fine for me.

Using new chains are of no concern with UG cogs. I use the nickel KMC chains, but any good chain is fine. There is no magic with a old UG chain.

John

thook

I have three uniglide 7spd hubs that are hyperglide comatible. All three have the one wide spline, but also have accommodation for the UG thread on locking cog and/or HG the lock ring. You sure you hub is not like this?

70sSanO

I have been swapping older freehub bodies on a few bikes lately. I watched RJ's conversion video, and while I admire his disassembly process, someone just shoot me if I am ever so inclined to to disassemble a freehub body unless it is absolutely the very last resort.

Here is the way I would approach your situation...

I believe the FH-6400 freehub body is a shallow flange (I recently installed a 6401), so you need to find a hub that has a 7 speed Uniglide/Hyperglide freehub body from an FH-MT62, FH-DX-650, FH-1055. The Shimano Part# is Y32E98020. The only caveat is that I have not installed a UG/HG or HG of a FH6400, but I believe the freehub body attach splines are the same.

The one I am talking about is the lower left. The lower right is an 8 speed 6401. Note: The bottom row is shallow flange and the top is a deep flange.



If you get a complete hub, NOS will cost a bit more, you can use the DS cone and it will match the freehub body. Best part of this approach is not having to corral a thousand freehub body ball bearings.

John

KCT1986

I second most of what John says in his post.

Would really not want to totally disassemble a freehub body and deal with the bearings and spacers needed to get a good preload on the bearings. Although, finding a 7 speed freehub body with the correct attachment method is tough now, so this may be the only way.

Many of the older 7 speed freehubs, in addition to those mentioned above, would work, but finding one in good condition is getting difficult. Note that some of the later 7 speeds are Hyperglide only, they no longer had the external threads to use a Uniglide lockring, if that matters.

One correction to John's description of his picture, I believe that the lower right body is from an 8 speed FH-6402 (or similar). The FH-6401 was a 7 speed version that was similar to the bottom left body shown, with threads on both the outside for Uniglide and inside for a Hyperglide lockring.

Swapping in an 8 speed freehub body is possible but note the following:
1. For a 7 speed cassette, a spacer will be needed behind the cassette to move it out enough to get tension on the lockring.
2. The 8 speed freehub body will probably have the position of the bearings further out, so the overlocknut distance will be greater. This will mean that the hub will no longer be 126, more in the 128-129mm range.

70sSanO

You are absolutely correct. The older I get the more difficult is becomes to tell my right hand from my left… lol!

I used the 6402 freehub body, lower right, on an FH-DX650, to run an 8 speed cassette.

Ebay is most likely the only source for older 7 speed UG/HG freehubs. It is hit or miss, but try to find one that appears to be well kept and little wear marks. Every now and then an NOS pops up, pretty expensive.

I’ll soak an older freehub body in citrus cleaner, blow out the excess, let it dry thoroughly, and then let Phil’s oil soak into it until it quiets down.

John

icemilkcoffee 

Ebay always has some new 7 speed freehub bodies listed, BUT note that these bodies do not have the dust shields. You are supposed to somehow yank out your existing dustshield and press them into the new freehub body.

wrk101

Those aren't Uniglide hubs. Those are first generation hyper glide. When Shimano first came out with hyper glide, they made it compatible with Uniglide cassettes. Later, they eliminated the Uniglide threading.


https://www.sheldonbrown.com/k7.html