Crossover tandem drive would be left hand drive, but with proper pedal threading. I don’t know if there were any tooth count limits, though.

I picked up a left hand freewheel with a matching right hand freewheel from ebay, I got a double-sided rear hub from Amazon, found a set of Tandem cranks here and I am planning to build a double cranked, double chained freewheeled bike someday. Just need to build a wheel and find a suitable frame.

Older thread, my apologies - couldn't see any reason to start anew.

I saw my first left hand drive bike at the pump track today. Obviously BMX. Not only was the drive side odd, but the brakes were odd - there were none. No way to slow the bike. Not even a coaster brake or a fixie. The rider put his heel on the rear tire and did a controlled fishtail slide to stop.

I know this is an old thread, but it just popped up, so hear me out - on a regular track, wouldn't the outer side of the bike (the RHS) be traveling marginally faster than the inner side of the bike (the LHS), and therefore anything you could do to minimize drag on the RHS (eg. by moving the drivetrain to the LHS) would reduce the overall drag of the bike. Now let's discuss angels dancing on heads of pins

Clearly I'm bored - the 2012 London Olympic track was 250m with 85m "curves" - this equates to a 27.06m radius. Assuming a bike cleaving to this radius, and assuming a 10cm difference between the RHS drivetrain and a putative LHS drivetrain (I'm assuming 10 cm across the BB), the LHS drivetrain would describe a 26.96m radius (84.69m curve distance) in the time the RHS chainring travelled 85m - 99.6% of the RHS drivetrain speed through the air. Given that drag is a cube function of speed, this would mean that drag on the LHS drivetrain would be 98.9% that of the RHS drivetrain. A potentially significant marginal gain?

Drag force is a squared function of speed, not cubed.

And that little glitch really is a significant difference.

There was also a LHD Chinese (maybe?) bike at the Olympic track. It was pointed out by the commentators.

Team Japan used left side drivetrains in Paris 2024. Team USA and Team UK have used them in the past. Their lack of widespread adoption suggests that they haven't had the impact expected.

But drag power is a cube function of speed, and power is what we are normally talking about

Yeah, fair point.

https://cyclingmagazine.ca/spotlight...ally-olympics/

Dan

That’s interesting. Looks like the aero advantage is from the yawed airflow striking the drive side first.

The article also mentions more weight on the inboard side, which I would call a marginal marginal gain. Perhaps a micro-gain!

Only the Japanese team bike had a left-side drivetrain at the 2024 Olympics, which suggests that any advantage is very small. Otherwise they would all be doing it as standard.

https://www.bikeradar.com/news/paris...ope-lotus-bike

They claim it a huge gain.

[QUOTE​=CanadianCycling] ​From a rider’s perspective, you’re not losing anything by having the crank on the opposite side. But again, aerodynamically, that makes a huge difference. [/QUOTE]

Dan

Yeah I read that and immediately thought that if it really did make a “huge difference” then why is it not standard practice by now?

In that world of microseconds I would suspect that they had no impact at all.

Can't have been that good, they came second to the British ladies. :-)

You could also maybe make an argument from weight distribution like an oval racing car.

They did make that argument, but it isn’t very convincing on a 7 kg bicycle!

Neither is the aero but every little bit helps