Originally Posted by
fietsbob
Only freewheel threading that would be left hand thread would be on a rear hub made to have the drive on the left end.
Read again. I didn't say "freewheel threading" I said the freewheel outer race, the ring that the outer bearings run on. Like most of the other LH threads on a bike, it's LH thread to prevent loosening due to epicyclic forces from the bearings. The fixed cog lock ring is the only one that's different in that regard.
But I have made a "lefty", a LH drive bike. Takes people a second to figure out what's different. Pino Morroni did one many years ago, and then Felt recently resurrected the idea for the USA track pursuit bikes. Pino's theory being that the extra weight is lower on the track and travels a shorter distance than a regular RH drive bike, using less energy. Felt also claimed an aero advantage IIRC
Originally Posted by
fietsbob
tandem hubs has left ends threaded but that was for a brake, so was made tighter when the brake was applied
(near-trivia) old Regina Freewheels had the 2 largest cogs LH thread against the shoulder in the freewheel body.
Yes, that's right, good catches both. I'd suspect some antique hubs had LH threads on one side of the axle too.