Shimano Front Freewheels System '70s tech.

[Retrorockit]

I got my Wide Narrow chain rings form China. I got a few sizes in case the chainlime shifted. Also IDK what I really need at 70yo.
It's together and running. Switching to the square taper BB was easy. The freewheel needed a BB locknut for a spacer, but also needed to be all the way on the crank to clear. It took a couple tries but it actually fit, which doesn't always happen with things like this. Chained it up and went for a ride. Nothing seemed different. Oh yeah I forgot to add the magic zip tie between the cassette and spokes to soft lock out the rear freewheel. Now it's working. The W/N ring and 11s clutch derailleur seem to keep the chain on. I'll add the recumbent Idler chain guide anyway because the freewheel is a single speed part and noy intended to have side loads on it's single ball bearing. I'll get some photos up, but it looks much like the vinatge XT stuff I ttok off.
TBH this might not be worth doing on just a pedal bike. But for mid drive Ebikes, or technical offroading it has a lot to offer. Hub Motor Ebikes are on the menu now too. Not very retro stuff for the most part. But FFS rides again.
One thing is the freewheel clicks at crank speed now instead of wheel speed. If it's too fast or too slow you know you need to shift.

 

[Retrorockit]

I put this together. I went with a 42t chain ring after making sure a 46t would work. I also got rid of the godawful heavy Shimano M5100 11-51 discus cassette ( after making sure it would work). Since I had the Mavic hub that accepts Shimano 11s road cassettes I went to the other extreme with the ultralight Prestacyle monoblock 11-40t cassette ( actually a 2nd alloy block for the 2 largest sprockets). It's offered as a gravel bike part. More in character for the lightweight XC bike. This cassette won't fit regular MTB hubs. I found it discounted quite a bit.

Prestacycle UniBlock HG 11sp Cassettes

Prestacycle UniBlock HG 11sp Cassettes :: From $124.99 :: Prestacycle 11 Speed Cassettes

www.universalcycles.com

So the Thorn tandem stoker freewheel cranks and 73mm BB from SJS Cycles ( nice light alloy parts), the White ENO Ebike flanged BMX racing freewheel, and 110BCD adapter from Sick Bike Parts Ebay closeout. These all bolted right together with a nice close fit in places I added a 15t Terra Cycle recumbent chain idler on their Ebike battery frame clamp. This is to feed the chain straight onto the chain ring like a single speed since the ENO BMX feewheel has just one bearing. I have a 2 bearing freewheel of unknown provenance that might work w/o the chain guide.
I went with 2 small zip ties at the spokes to the cassettte. The small straight pull Mavic hubs, and hollowed out CNC cassette made a friction ring difficult to install there. Since I've lost the triple front derailleur setup going to 1x 11s, and have a lightweigh casette I'm probably breaking even on the weight factor. Shifting matches my Ebike now, and this mod work like a Rapid Rise setup as long as the bike is moving (which the 8 speed Ebike also has) Downshift without pedaling (upshift too). The SRAM NX11 speed gripshifter is very handy for this.

 

[Retrorockit]

Well I've come up with another little twist in this rather convoluted project. I began to suspect that the White ENO Ebike freewheel could accept the inner workings of their Trials freewheel. This adds 3 more pawls for 72 clicks per revolution (up from 36) for a 5* engagement angle. This seems to be a big deal for trials and technical offroad riders. So why not see if that works too. Yes it does. White sells the 6pawl driver separately, and it comes with the pawls ready to install. My LBS works om anything that comes in the door, and they've been at it quite a while. It's not easy to surprise them but I think this will probably do it.

 

[Retrorockit]

It turns out that the SJS/Thorn tandem BB axle is an unusual 134mm width. It fits with the ENO on a 73mm BB shell with 1mm to spare and a normal chainline for a 46t cog. If you need wider that might be tough with those parts. I do have the Ebay square taper and ISIS cranks for the ENO. I'll have to see how those fit up on available bottom bracket widths. The seller used incredibly wide bottom brackets to clear the huge motors they were installing. 200mm +. I bought the set and thought it was just normal sized parts but it seems to be an unusual size.. I'll have to dig out another frame and see what lines up with the other cranks. I've managed to get a lot of mismatched parts working well together on this bike. i'm not going to change a thing on this one.

 

[Retrorockit]

Plan B on this mod. I got all the parts from one Ebay vendor for this 2nd version. Much more modern than the Thorn/ SJS Cotterless Axle setup.
With a sealed cartridge square taper BSA 68x131.5 bottom bracket it made a 60mm chain line, with 10mm between the Freewheeland the RH bearing Cup. I just set this up on a bare frame. I did convert it to 73mm with a Shimano LH bearing retainer. So a lot more chainline options with normal sized BB. And probably a couple mm smaller on a 68mm frame. Much stouter MTB type cranks and BBsetup. This will be shipped off to NYC for beta testing by my little brother.

 

[Retrorockit]

The 68x131.5 square taper BB converted to 73mm (using a Shimano ES71 LH cup) lines up perfectly with the SJS/Thorn cranks, and ENO. So no more 134mm Cotterless Axle nonsense.
I have another trick up my sleeve ( which may or may not work out).
It's a very retro SRAM 9.0 Half Pipe 8 speed gripshifter. I think it will work with an 8speed cassette and a Shimano 11s clutch type derailleur.
This is for an Ebike, but it's a converted 2004 Gary Fisher. So vintage shifter with modern 11s chain and derailleur on an old 8s Bike. Aside from the clutch derailleur this gets me into some wide range cassettes also. Watch out for Linkglide stuff. It's weird even by my standards.