TLaurent 

I have a couple tandems and find it difficult to find a willing stoker because most riders prefer to pedal at their own pace. I don’t mind doing most of the work and have been searching for a solution to enable the stoker to coast while the the captain can continue pedaling. I even bought a set of foot rests to install for the stoker but finding a location to install them w/o obstructing the captain’s heals has been a challenge. I recently discovered the Shimano FFS and think that this might be the solution that I’m looking for. One bike is a 70s Gitane tandem with an odd shaped BB so it’s not a good candidate. The other is a Yakota Grizzley that’s likely ISO so the odds of finding an FFS to fit are better. Has anyone used this system?

roytar

I'm in the process of converting my wife's FFS based Schwinn world tourist to single speed coaster brakes. If you find out the world tourist FFS is compatible with your needs, I'll gladly send it to you.

TLaurent 

Thank you for offering! I have an adapter for Schwinn bottom brackets and would like to try. Please let me know what you would like for the FFS. I’m located in Saint Paul, MN. -Trent

roytar

I pulled the cranks off but need the old style tool to remove the bottom bracket caps. Ordered it online should come in a couple of days. I want to make sure a standard BB will fit.
So it may be a few days....

TLaurent 

Sounds good. Some of those older BBs are difficult to remove. Good thing the BF has many knowledgeable members.

roytar

Are you still interested? I finally completed the FFS to coaster brake conversion.
You can have the FFS for the cost of shipping.
I couldn't separate the chainrings from the BB axle. Some photos:

roytar

Are you still interested? I finally completed the FFS to coaster brake conversion.
You can have the FFS for the cost of shipping.
I couldn't separate the chainrings from the BB axle. Some photos:

plumberroy

Ross bikes used these too . I actually think it's a good system for an around town bike. You can shift to a lower gear coasting up to a stop

Leisesturm

I don't know ... IPS has been a thing much more recently than FFS systems which (tmk) have never been offered on the Schwinn tandems of the day. I would like to see the 'math' of obtaining IPS this way vs something like a DaVinci or Santana system. To me, it's problematic that the rings cannot be removed because a standard 'crossover' system is not going to be possible (afaics). Two rings of the same size are going to be necessary on the drivetrain side of the bike. And the captains crank will need to match those sizes.

TLaurent 

@roytar DM sent. Thank you!

Numenor

I am restoring bike for friend of mine, and he have this ffs crankset. But as i see, ball berings inside system are missing. Do you maybe know size and number of them?
Thanks a lot in advance

Numenor

roytar

Do i need 2 different ball bearings size? I can not remember are they suppose to be here (under lock ring) also?

TLaurent 

Yes, bearings appear permanently installed to the crankshaft. The set that roytar sent are in the shop at my other place so it may be a week or so before I can attempt to measure them.

Numenor

Just reminder for ball bearings size 😉

TLaurent 

Numenor , apologies. Death in the family and it might be a few weeks before I get to the location of the FFS. I saw that you posted the question in another thread and promise to post the findings here when I can. Peace & love.

Numenor

Very sorry to hear that!
Do not wory, there are more important things in life than old bike parts.

I hope that you will fond comfort in days ahead!

Best regards!

TLaurent 

Numenor , I appreciate the words. I find comfort in C&V and problem solving these old machines. That said, I measured the bearings with a digital caliper since it doesn’t come out to use a bearing guage. There are 24 that measure 3.94mm. Let me know if you would like additional measurements on these.

rickpaulos

Shimano FFS was mfd in several versions.

1 piece "Astabula" cranks provided on a few million Schwinns bikes like the Caliente and World Tourist. Probably accounts for 95% of all FFS sold.

3 piece cotterless steel arms in single or double ring versions. The single ring version was used on 5 speed bikes. Mostly seen on Panasonic bikes.

3 piece cotterless alloy double ring with the spline axle. (least reliable version). This was one of Shimanos first splined cranks and they tended to fail at the splines. Rather rare, I'd guess less than 1% of FFS cranks sold.

I put two 1-piece FFS cranks on a 1960s Columbia Twosome as an experiment. Yes, you get independent pedaling but both riders still pedal at the same rpm. The Columbia tandem was a 1 speed coaster brake bike so no braking by back pedaling. The Columbia had a feeble front hand brake so that was the only brake. The frame was not drilled or drillable for a rear caliper brake. Lucky the chain tensioner was not needed as the connection chain fit perfectly. The FFS sprockets have inside and outside chain guards so the chain never came off. The FFS cranks came off after a few rides.

DaVinci makes a tandem with a mid drive and independent pedaling that can be reconfigured for different rpms.

I had a Huffy Bicycle Built for Two with different size connecting sprockets. This does allow for the riders to pedal at different rpms. It kinda worked. Funky to watch. Constantly variable phasing. The bike was rather flexible so when the cranks were in phase the bike would bounce up and down, when 90 degrees out of phase, it would snake down the road and this kept repeating. A few pedal strokes in each mode. Other riders would follow us just to watch the show. How quickly this pattern repeats depends on the relative size of the connecting sprockets. Fast cornering can be a problem as the captain never knows where the rear pedals are. Definitely a no-no for tandem criterium racing.

Shimano FFS was usually supplied with Positron but not always. I've seen bikes with one but not the other. FFS was intended for clueless consumers who could not understand the basic rule of you have to be pedaling to shift gears. Positron index shifting went along with trying to simplify 10 speed bikes.