Are Shimano freehubs compatible with Formula hubs?



C

Chalo

Guest
Tom Sherman wrote:
>
> Andrew Muzi wrote:
>
> > Tom Sherman wrote:
> >>
> >> Why would anyone prefer a freewheel over a cassette? Particularly a
> >> Chalo sized person?


Freewheels are more robust and far cheaper than equivalent cassettes.
And when you replace the sprockets, you get a new ratchet in the
deal.

> > Strong riders break off the little underdesigned Shimano cassette pawls.

>
> >

> Do not heavy riders break freewheels axles more often compared to free
> hub axles? Or even Jobst Brandt mass riders who spend a lot of time out
> of the saddle?


When the axle in question is a hollow piece of 10mm allthread-- yes,
it's a problem. But a freewheel hub axle need not be so flimsy-- up
to a 19mm round can fit within the void on a Shimano-style freewheel
remover. A 6902 cartridge bearing (15mm ID) fits nicely inside the
thread of a freewheel hub shell, and has plenty of load capacity for
the job. A cassette hub's axle generally is limited to 10mm with a
threaded surface, unless the ratchet body's integrity is compromised
to accommodate something larger.

> I can also imagine a Chalo sized rider would get a freewheel rather
> tight on the hub just through normal riding.


That is a serious issue for two-prong Suntour freewheels, and even for
four-prong versions of the same. It is not a problem for Shimano and
Sachs freewheels, which use a splined remover tool.

> The Shimano complaint would seen to indicate a problem with a specific
> implementation, and not a general condemnation of the general design.


In principle, the axle of a cassette hub can grow slightly in diameter
and be unthreaded on its surface. In practice, that means the ratchet
mechanism must reside in an even thinner space between the cassette
splines and the axle. Shimano's freehub represents an optimum balance
between the strength of the ratchet and the strength of the axle.
Neither one is as strong as easily possible with a freewheel hub.

A cassette hub could be made stronger, with more room for a strong
axle, but the minimum sprocket size would have to increase.

The problem of overtightening of the freewheel thread could be
addressed by use of a multi-start helical spline like Maillard
Helicomatic, but in practice the 1-3/8x24 freewheel thread works well
enough to justify its simplicity and low production cost.

Shimano's real coup in bringing cassette freehubs to the mass market
was that they circumvented the worst design liability of freewheel
hubs while keeping the 10mm threaded axle. To me that looks like
figuring out how to add a bead hook to single-walled steel rims--
missing the point and the opportunity for real improvement. The drive
side overhang is not the basic problem; it's the skinny threaded
axle. With the cassette freehub, Shimano kept the fundamental problem
component and made it more difficult to use a better alternative.

Chalo
 
L

landotter

Guest
On Feb 13, 9:53 pm, Brian Huntley <[email protected]> wrote:
> On Feb 13, 9:56 pm, landotter <[email protected]> wrote:
>
>
>
> > On Feb 13, 8:20 pm, Brian Huntley <[email protected]> wrote:

>
> > > On Feb 13, 2:02 pm, landotter <[email protected]> wrote:

>
> > > > I'll be sure to update everybody on the minutia of my dog food
> > > > fetcher! LOL The stories I could tell about the mounting of the bell,
> > > > the kickstand, and the operatta that was the upgrading of the mud
> > > > flaps! Steven Sondheim should hear my inspiring tale!

>
> > > When you're a Dew,
> > > You're a Dew all the time
> > > From your eight-speed cassette
> > > To your bell's double chime!

>
> > > When you're a Dew,
> > > If the spit hits the street,
> > > You got brothers around,
> > > You're a part of the fleet!

>
> > > You're never alone,
> > > Your chain's not disconnected!
> > > You've a lane of own:
> > > When traffic is expected,
> > > You're well protected!

>
> > > Then you are set
> > > With a capital D,
> > > Which you'll never forget
> > > Till they saw your lock free!
> > > When you're a Dew,
> > > You stay
> > > A Dew!

>
> > BRAVO!

>
> > > (I'd do something more up to date, but can't hum Sweeney Todd.)

>
> > These are my friends!

>
> >http://www.youtube.com/watch?v=rLQCMj-GGIA

>
> Without the video, I'd have thought that song was about Campy downtube
> shifters.


Sounds like a hilarious P-shop project...