FFS - front freewheel system

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

"Jacobe Hazzard" wrote in message
ble.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................

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

In article . rogers.com,
Jacobe Hazzard 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

"Jacobe Hazzard" wrote in message able.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

Carl Fogel wrote:
"Jacobe Hazzard" wrote in message
able.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

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

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

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


-

Carl Fogel wrote:

"Jacobe Hazzard" wrote in message able.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

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? 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


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


-

Sheldon Brown wrote in message ...
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

Dan Burkhart wrote:
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


Autobike was selling by infomercial last year

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


-