FFS - front freewheel system

Jacobe Hazzard

I am rebuilding an old panasonic road bike I found, and it
is equipped with shimano FFS, that's where the BB spindle
freewheels.

This is bizarre, the chain moves when I'm coasting!
What's the purpose of such a system? When I found the
bike it had a 5 speed freewheel on the rear wheel, and
the wheel + derailer look pretty old, not like they were
added on late in the life of the bike, so that makes the
FFS pretty useless.

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

Thanks guys!

Adam

Dave Thompson

"Jacobe Hazzard" <spamsink@ATeudoramail.DOTcom> wrote in message
news:0gx3c.226115$Qg7.94774@news04.bloor.is.net.cable.rogers.com...
> I am rebuilding an old panasonic road bike I found, and it
> is equipped
with
> shimano FFS, that's where the BB spindle freewheels.
>
> This is bizarre, the chain moves when I'm coasting! What's
> the purpose of such a system? When I found the bike it had
> a 5 speed freewheel on the
rear
> wheel, and the wheel + derailer look pretty old, not like
> they were added
on
> late in the life of the bike, so that makes the FFS pretty
> useless.
>
> Also, where is the front freewheel exactly? Is the BB
> shell the standard size, or is there something special
> about it?
>
> Thanks guys!
>
> Adam
>
>
According to Sheldon Brown's web-site: FFS ® Front Freewheel
System. The freewheel was built into the bottom bracket, so
that the chain would turn even when the rider was coasting.
This was to allow shifting while coasting--a solution in
search of a problem.

Apparently it wasn't terribly popular and didn't last long.
I don't know anything about it other than what I found doing
a quick goodle search. Maybe ol' Sheldon will drop
by................

Sheldon Brown

Jacobe Hazzard wrote:

> I am rebuilding an old panasonic road bike I found, and it
> is equipped with shimano FFS, that's where the BB spindle
> freewheels.
>
> This is bizarre, the chain moves when I'm coasting! What's
> the purpose of such a system?

Beginner cyclists don't always realize that you need to be
pedaling to shift a derailer. This was especially true of
folks who started out on internal-gear 3-speeds.

> When I found the bike it had a 5 speed freewheel on the
> rear wheel, and the wheel + derailer look pretty old, not
> like they were added on late in the life of the bike, so
> that makes the FFS pretty useless.

See: http://sheldonbrown.com/shimano1982/pages/35.html

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

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.

There was also a variant that used a one-piece crank,
fitting into a standard American-type bottom bracket shell.
I used these to make coastable kidback tandem cranks when my
kids were little.

Sheldon "An Idea Whose Time Has Gone" Brown +------------------------------------------------
+
| What was the real cause of the 1861-65 war? |
| http://sheldonbrown.net/slaverywar.html |
+------------------------------------------------+ Harris
Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX
617-244-1041 http://harriscyclery.com Hard-to-find parts
shipped Worldwide http://captainbike.com
http://sheldonbrown.com

Eric H

In article <0gx3c.226115$Qg7.94774@news04.bloor.is.net.cable.rogers.com>,
Jacobe Hazzard <spamsink@ATeudoramail.DOTcom> wrote:

>This is bizarre, the chain moves when I'm coasting! What's
>the purpose of such a system?

The idea was that the chain keeps moving, so that you can
shift when you coast, in case you find shifting while you
pedal too difficult.

Somebody must have thought it was a good one, at some
point...

--
---
"I never had to pretend I felt the lyrics. I could always
relate to the words."
-- Teddy Pendergrass

Carl Fogel

"Jacobe Hazzard" <spamsink@ATeudoramail.DOTcom> wrote in message news:<0gx3c.226115$Qg7.94774@news04.bloor.is.net.cable.rogers.com>...
> I am rebuilding an old panasonic road bike I found, and it
> is equipped with shimano FFS, that's where the BB spindle
> freewheels.
>
> This is bizarre, the chain moves when I'm coasting! What's
> the purpose of such a system? When I found the bike it had
> a 5 speed freewheel on the rear wheel, and the wheel +
> derailer look pretty old, not like they were added on late
> in the life of the bike, so that makes the FFS pretty
> useless.
>
> Also, where is the front freewheel exactly? Is the BB
> shell the standard size, or is there something special
> about it?
>
> Thanks guys!
>
> Adam

Dear Adam,

A friend's father bought a bike equipped with this odd
system when I was in high school. We all marvelled at the
strange way that the chain kept moving, but none of us had
any idea of the purpose. Apparently, they were sold without
dealers having a clear notion, either.

Thanks for raising a long-forgotten question and getting the
others here to provide the answer.

Carl Fogel

meb

Not a longforgotten question since you can mount Powercranks with a fixie rear with similar results.

Several electric bikes, including a couple of my Currie's, use a left side electric chain drive with the freewheel attached to motor side of the chain drive. Unfortunately, another problem with these implementations are that you are still turning the second chain even when not running the electric drive so you are introducing extra frictional losses-about 1%. The analagous situation would exist on the FFS or Powercranks-fixie combinations during coasting.

Christini and Spicer AWD mountainbikes probably have similar issues with the front drive.

Robert Brown

Carl Fogel wrote:

> "Jacobe Hazzard" <spamsink@ATeudoramail.DOTcom> wrote in
> message news:<0gx3c.226115$Qg7.94774@news04.bloor.is.net.-
> cable.rogers.com>...
> > I am rebuilding an old panasonic road bike I found, and
> > it is equipped with shimano FFS, that's where the BB
> > spindle freewheels.
> >
> > This is bizarre, the chain moves when I'm coasting!
> > What's the purpose of such a system?

----8<---cutting

>
>
> Dear Adam,
>
> A friend's father bought a bike equipped with this odd
> system when I was in high school. We all marvelled at the
> strange way that the chain kept moving, but none of us had
> any idea of the purpose. Apparently, they were sold
> without dealers having a clear notion, either.
>
> Thanks for raising a long-forgotten question and getting
> the others here to provide the answer.

I heard about this one years ago. The only advantage I
could see with this system is that it allows the rider to
shift gears while coasting, i.e. without turning the
pedals. Now why on earth someone would . . . aw, forget it
. . . ROTFL . . .

/Robert

Dan Burkhart

A few years ago, the "auto bike"made use of this concept. It used a 5 speed rear cassette and there were weights on the wheel which moved toward the outer part of the wheel by centrifugal force as the speed of the bike increased. These weights were linked to the derrailuer so that as the speed increased, and the weights moved out, the chain automatically moved to a smaller cog. The reverse happened as the bike slowed down. The freewheeling chainwheel was necessary so the shifts would happen even if the rider was not pedalling. I don't know whatever became of the Autobike.
It occurs to me it might be useful on a tandem for those who prefer indepedent pedalling

__________________
Dan Burkhart
Oakville Ont
www.boomerbicycle.ca

Jeff Wills

Sheldon Brown <CaptBike@sheldonbrown.com> wrote in message news:<404EA36B.8030906@sheldonbrown.com>...
> > Also, where is the front freewheel exactly? Is the BB
> > shell the standard size, or is there something special
> > about it?
>
> 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.
>
> There was also a variant that used a one-piece crank,
> fitting into a standard American-type bottom bracket
> shell. I used these to make coastable kidback tandem
> cranks when my kids were little.

To answer a question Sheldon missed: the BB shell on your
Panasonic should be a standard 68mm width English thread
unit. IIRC, once you get the arms off the spindle, the left
cone unscrews from the spindle and the bearings fall on the
floor. After removing the spindle to the right (and
dropping more bearings), you'll see that the cups threaded
in the frame have internal splines. I *think* the tool that
fits these splines is the standard Shimano freewheel
removal tool.

A note: the rear cogset had a limited freewheel action built
into it. If something jammed the chain, this would allow the
rear wheel to continue to turn. It felt like a conventional
freewheel with *really* tight bearings.

Jeff

meb

Autobike was selling by infomercial last year.

There website is still operational:
http://www.bpc.co.kr/

Jacobe Hazzard

Thanks everyone, you answered all my questions.

I found something else interesting today, a dynohub front
wheel. I know what that's for. There are a lot of
interesting things getting thrown out if you stop and look!

Adam

Jeff Wills

"Jacobe Hazzard" <spamsink@ATeudoramail.DOTcom> wrote in message news:<6hU3c.179294$sl.128521@news01.bloor.is.net.cable.rogers.com>...
> Thanks everyone, you answered all my questions.
>
> I found something else interesting today, a dynohub
> front wheel. I know what that's for. There are a lot
> of interesting things getting thrown out if you stop
> and look!
>
> Adam

A working Dynohub would be neat- but if it's been
dissassembled, the magnets may have been ruined (I think).
Sheldon may be able to help:
http://www.sheldonbrown.com/dynohubs.html

Jeff

Eric St. Mary

Trials riders are using a similar system now. They attach freewheels to the cranks.

http://www.webcyclery.com/.docs/pro...ct_details.html

Be Well,
Eric

meb

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?