Early Shimano freehub body curiosity



M

Mark Janeba

Guest
I had an interesting experience last week, which I present here as an
RBT curiosity. A friend had a cassette that was slipping under
pressure. Turns out it wasn't the chain.

I suspected gummed-up pawls, and suggested he bring it by for a look. It
was a very old Shimano freehub, and sure enough the cogs turned
clockwise with very little effort, but it didn't feel like munged pawls
either.

When I went to access the pawls (I've done this before with freehubs),
even the inner part of the freehub body was turning clockwise (so I
couldn't unscrew the left-hand-threaded bearing cup.)

As I said, the hub was one of the oldest Shimano freehub designs (no
bulge on the aluminum hub shaft). Rather than mount with the usual 10mm
screw, this body mated to an aluminum spline on the outside of the hub.
The aluminum spline was ripped up beyond recall. Curious, since the
rider is an older recreational rider, though he was geared quite low.
(Of course we had to replace the wheel).

Finally found an image of one of these hubs at (where else):
http://www.sheldonbrown.com/k7.html#advantages
The drawing shows the spline on the right side of the hub body.

Question 1: Anybody seen this failure before? Was it the reason Shimano
dropped this design so quickly?

Question 2: Does anybody want the freehub body? It should be reusable
if you have a hub to match (though I can't imagine a situation where
you'd need it - I'd expect other failure to be like this one.) Available
for the price of shipping.

Mark
 
D

Dave Mayer

Guest
"Mark Janeba" <[email protected]> wrote in message
news:[email protected]
>I had an interesting experience last week, which I present here as an RBT
>curiosity. A friend had a cassette that was slipping under pressure.
>Turns out it wasn't the chain.
>
>
> Question 1: Anybody seen this failure before? Was it the reason Shimano
> dropped this design so quickly?


This was a very early Shimano freehub design. Circa 1980. The freehub body
was press-fit onto the aluminum hub shell. What held the hub and freehub
together was a thin male projection extending out of the hub shell. And the
compression force of the quick release. The next generation of attachment
showed up in Dura-Ace, in which the Dura-Ace specific freehub screwed into
the (female socket) hub shell. This was not a good design, in that the
freehub tightened with pedaling, and it required a special tool (and a lot
of force) to remove it from the hub shell. Finally, the third Shimano
design iteration had the freehub attached to the hub shell with a 10mm
hollow bolt. Mid-80's, and still the current design.
>
> Question 2: Does anybody want the freehub body? It should be reusable if
> you have a hub to match (though I can't imagine a situation where you'd
> need it - I'd expect other failure to be like this one.) Available for the
> price of shipping.
>

The freehub is either a 5 or 6-speed Uniglide. Pretty thin market for
these.

These old hubs are still nice, in that without the 10mm fixing bolt, and the
matching threaded bulge in the hub shell, these are the lightest hub shells
around. The neat trick for a road setup is to pull the old freehubs off of
these hubs, and press-fit on a Shimano titanium 9-speed freehub, and fit it
out with a ti axle and ceramic balls. To bad the aluminum splines on your
hub is stripped. I have been riding on these hubs for '000's of miles. I
have never seen the type of failure you describe, but I can see how it could
happen. Your pal might have been mashing on the pedals when the rear quick
release came loose.
 
N

Nate Knutson

Guest
Dave Mayer wrote:
> These old hubs are still nice, in that without the 10mm fixing bolt, and the
> matching threaded bulge in the hub shell, these are the lightest hub shells
> around. The neat trick for a road setup is to pull the old freehubs off of
> these hubs, and press-fit on a Shimano titanium 9-speed freehub,


Does this work just like that without having to do anything else? Any
other info?

Thanks
 
A

A Muzi

Guest
Mark Janeba wrote:
> I had an interesting experience last week, which I present here as an
> RBT curiosity. A friend had a cassette that was slipping under
> pressure.

-snip-
> As I said, the hub was one of the oldest Shimano freehub designs (no
> bulge on the aluminum hub shaft). Rather than mount with the usual 10mm
> screw, this body mated to an aluminum spline on the outside of the hub.
> The aluminum spline was ripped up beyond recall. Curious, since the
> rider is an older recreational rider, though he was geared quite low.
> (Of course we had to replace the wheel).
>
> Finally found an image of one of these hubs at (where else):
> http://www.sheldonbrown.com/k7.html#advantages
> The drawing shows the spline on the right side of the hub body.
>
> Question 1: Anybody seen this failure before? Was it the reason Shimano
> dropped this design so quickly?


Yes that's the normal failure mode. Notice also that the
hubshell is in two pieces. The seam is under the sticker.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 
C

Chris Z The Wheelman

Guest
I had one of those myself, still do, actually, though it has been
retired to a life of ease in my spare parts box. And being one to remove
the cogset regularly for cleaning, I noticed the same thing happening.
Being a tourist/recreational rider, I don't put much strain on my gears
either.

The problem is as you state. The cogset was held to the hub by the
pressure between the bearings. If they are adjusted correctly, there
should be NO play, as this would cause the interface between the splines
to wear. Which, after 50,000 miles or so, mine had. Though not to the
extent you describe (about 50% of the aluminum spline still remains on
the hub).

This was also the reason for the design change, which is actually a
modification. The hub/cogset interface is basically unchanged, both
parts still have a very similar spline, but now they are held together
tightly by a 10mm bolt, which prevents any movement between the cogset
and the hub.

The swelling in the hub allows for the 10mm threading for this bolt.

- -
These comments compliments of,
Your Friendly Neighborhood Wheelman

My web Site:
http://geocities.com/czcorner

To E-mail me:
ChrisZCorner "at" webtv "dot" net
 
D

Dave Mayer

Guest
"Nate Knutson" <[email protected]> wrote in message
news:[email protected]
>


> Does this work just like that without having to do anything else? Any
> other info?
>

Pull the old freehub off. If it is on tight, you may have to be creative to
make this happen, but do not use a anything to try and wedge it off. I used
a thread-on freewheel body, some washers, a threaded hub axle and a bunch of
axle spacers and spare cones to jerry-rig a tool to pull mine off. Pull
being the operative word.

Once you have the old freehub off, notice the male aluminum protrusion that
will fit on the new freehub. Then look at the holes in the old and new
freehubs. Notice that your new freehub may have a slight lip where the old
one does not. To get around this, you may have to sand off about .1 to .2
mm of aluminum on the hub protrusion. Once there is a tight (but possible)
fit between the two, time to get out some green Loctite, a hammer and a
hockey puck to do a little press-fitting. Once things are connected, time
to put the hub guts back in.
 

Similar threads

E
Replies
7
Views
1K
N