Old Sturmey in modern shell?

Does anyone know (to save me trying it) whether the inner unit from a
Sturmey-Archer AM hub, or even an original AW hub, will fit in the
modern S-RF3 shell? The AM and AW are certainly interchangeable, but it
would be nice to have the medium-gear innards in a lighter shell. I've
already added an oil port.

In article ,
Zog The Undeniable wrote:

Does anyone know (to save me trying it) whether the inner unit from a
Sturmey-Archer AM hub, or even an original AW hub, will fit in the
modern S-RF3 shell? The AM and AW are certainly interchangeable,

So's an SA five speed.

but it would be nice to have the medium-gear innards in a lighter
shell. I've already added an oil port.

I'd be surprised if you could swap an old SA assembly into the new hun
shells, mainly because the new ones use a ball-locking clutch instead of
the old system.

Tim McNamara wrote:
In article ,
Zog The Undeniable wrote:

Does anyone know (to save me trying it) whether the inner unit from a
Sturmey-Archer AM hub, or even an original AW hub, will fit in the
modern S-RF3 shell? The AM and AW are certainly interchangeable,

So's an SA five speed.

but it would be nice to have the medium-gear innards in a lighter
shell. I've already added an oil port.

I'd be surprised if you could swap an old SA assembly into the new hun
shells, mainly because the new ones use a ball-locking clutch instead of
the old system.

I've had both apart and the shells look pretty much identical inside.

The main difference between the new NIG hubs and the old ones is that
the new ones have three sets of pawls. The ticking of the overdriven
pawls is different too - on an AW the low-gear pawls tick identically in
normal and top, on an S-RF3 the ticking is much slower in top. The
driver now has its own pawls and these are locked out by a slightly
crude sheet metal shroud which rotates with the clutch (a much deeper
one-piece affair) and covers them up when they're not meant to engage.

An S-RF3 can still squirm its way out of top under very high torque, as
Jobst is fond of explaining, but it can only slip into "normal", with no
neutral position. It's not as minimalist a design as the old hubs, but
it's more foolproof. The Taiwanese designers also made the ends of the
planet pins, which the clutch engages, the same thickness as the rest.
On the AW the protruding end is the thinnest part of the pin.

The worst thing about the new hubs is the grease lubrication. Fine for
a couple of years, then (unless you like tinkering) it's uneconomic to
have someone strip, clean and rebuild a hub you can buy built into a
wheel for 40 GBP. The old oil-lubricated ones didn't leak appreciably
unless overfilled, and they get better with age as the threads are
gunked up with road dirt. I imagine a bit of PTFE tape during assembly
would eliminate the usual seepage around the RH ball ring threads - I
must try it.