FFS - front freewheel system

A Muzi

> Jeff Wills wrote:
> > > > Also, where is the front freewheel exactly? Is
the BB shell the
> > > > standard size, or is there something special
about it?

> > Sheldon Brown <CaptBike@sheldonbrown.com> wrote in
> > message news:<404EA36B.8030906@sheldonbrown.com>...
> > >
> > > It's attached to the bottom bracket spindle. This
> > > precluded use of a standard square taper BB for
> > > clearance reasons, so they use an early "Octalink"
> > > splined setup that turned out to be rather
> > > unsatisfactory.
-snip informative stuff-

meb wrote:
> Am I correct in assuming this limitted freewheel action
> would preclude the rear cogset from being used for a 5
> speed fixie? Was this limitted freewheel action limitted
> enough to provide significant braking? Was there any
> weight difference on the FF rear 5 speed cogset from a 5
> speed freewheel or were they comparable?

The freewheel for an FFS/PPS has stiffer than normal
resistance and will allow a chain to bunch up when coasting
if you remove the FFS/PPS crank system.

If you set it up as a single speed ( You misuse the term
"fixie") by shortening the chain to one of the five
sprockets, yes, you can ride it effectively. Just don't
include a derailleur or tensioner unless you have the
special crank assembly.

The crank spline is the "Selecta" pattern which started the
early "standard" called "Octa-8" long before "octalink."

No, you will get no noticeable braking effect. Keep your
front caliper.

On a hi-ten frame with steel hubs, cranks and rims the
freewheel weight, while substantial, isn't all that
significant.

You may substitute a normal 5 or 6 freewheel ( or even a
single for that matter) on the hub you have.
--
Andrew Muzi www.yellowjersey.org Open every day since 1
April, 1971

meb

Not sure why the term fixie is missused. Is it because a 5 speed non-freewheeling drive (times any crankset ring quantities) is not a “fixie” if gears can be changed?

Regarding the tensioner issue raised: I was considering constructing a tensioner from the RANS double idler assembly http://www.shoprans.com/DriveLine.asp configured to move to take in tension from sprocket changes as well as allow the return chain side to switch to tension when the crank speeds slow below wheel speed. The double idlers are designed to work on the chain drive side as well as return side. Is there a nonobvious tensioner issue with “fixies” overlooked?

This would be tried on a recumbent.

A Muzi

-snip much-
> > meb wrote:
> > > Am I correct in assuming this limitted freewheel
> > > action would preclude the rear cogset from being
> > > used for a 5 speed fixie? Was this limitted
> > > freewheel action limitted enough to provide
> > > significant braking? Was there any weight difference
> > > on the FF rear 5 speed cogset from a 5 speed
> > > freewheel or were they comparable?

> A Muzi wrote:
> > The freewheel for an FFS/PPS has stiffer than normal
> > resistance and will allow a chain to bunch up when
> > coasting if you remove the FFS/PPS crank system. If
> > you set it up as a single speed ( You misuse the term
> > "fixie") by shortening the chain to one of the five
> > sprockets, yes, you can ride it effectively. Just
> > don't include a derailleur or tensioner unless you
> > have the special crank assembly.
-snip-

meb wrote:
> Not sure why the term fixie is missused. Is it because a 5
> speed non- freewheeling drive (times any crankset ring
> quantities) is not a “fixie” if gears can be changed?
-snip-

The FFS freewheels coasts. It's a freewheel, not fixed.

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

meb

So a Schlumpf BB drive with fixie hub is semantically a fixie even though multi speed.

Adam Rush

> So a Schlumpf BB drive with fixie hub is semantically a
> fixie even though multi speed.

Schlumpf themselves say that is it right out. From
their FAQ:

"9. Can speed-drive be used with a fixed wheel cycle?

"No. In reverse direction, there musn't be full load. It's
o.k. for actuating a coaster brake, but not for high torques
during long operation periods."

If anybody could give me some technical reasons for this FAQ
answer, other than that they are covering their asses, I
would appereciate it.

A Muzi

> > -snip much-
> > > > meb wrote:
> > > > > Am I correct in assuming this limitted
> > > > > freewheel action would preclude the rear
> > > > > cogset from being used for a 5 speed fixie?

note use of "freewheel" and "fixed gear" together.

> > > A Muzi wrote:
> > > > The freewheel for an FFS/PPS has stiffer than
> > > > normal resistance and will allow a chain to
> > > > bunch up when coasting if you remove the FFS/PPS
> > > > crank system. If you set it up as a single speed
> > > > ( You misuse the term "fixie") by shortening the
> > > > chain to one of the five sprockets, yes, you can
> > > > ride it effectively. Just don't include a
> > > > derailleur or tensioner unless you have the
> > > > special crank assembly.
> > -snip-

> > meb wrote:
> > > Not sure why the term fixie is missused. Is it
> > > because a 5 speed non- freewheeling drive (times any
> > > crankset ring quantities) is not a “fixie” if gears
> > > can be changed?
> > -snip-

> A Muzi wrote:
> > The FFS freewheels coasts. It's a freewheel, not
> > fixed.

meb wrote:
> So a Schlumpf BB drive with fixie hub is semantically a
> fixie even though multi speed.

Yes, I think we agree. "Fixed" implies no coasting.
Freewheels, whether one or eight speeds, are not fixed.
--
Andrew Muzi www.yellowjersey.org Open every day since 1
April, 1971

David Damerell

Adam Rush <adamrush@mail.com> wrote:
>Schlumpf themselves say that is it right out. From their
>FAQ: "9. Can speed-drive be used with a fixed wheel cycle?
>"No. In reverse direction, there musn't be full load. It's
>o.k. for actuating a coaster brake, but not for high
>torques during long operation periods." If anybody could
>give me some technical reasons for this FAQ answer, other
>than that they are covering their asses, I would
>appereciate it.

I'm not sure what you mean; manifestly it's harder to design
a planetary gear that must withstand high torque in both
directions.
--
David Damerell <damerell@chiark.greenend.org.uk> flcl?