Do you regularly run out of power on your chain powered bike though? I get the feeling this system requires a battery (it even mentions battery in the article), and most of the actual power comes from that. The question is, will the generator make enough power to get you moving if the battery is totally flat? I kinda feel like no, you'd have to sit there and pedal it just to charge it up, and then it would move you a few feet. Or you're going to be pedaling really fast, and moving nowhere.

They claim to be 5% less efficient than a chain. So with a dead battery, you'd be limited to a speed of 95% of what you could do on a normal bicycle. That's if you're already moving. If you were at a dead stop I imagine you'd need to pedal a few strokes to get enough charge to get enough torque to overcome the stiction.

Where do they claim that efficiency? I'm pretty skeptical... Chain+Derailleurs can be 98% efficient IIRC

Electric motors/generators are in the same range. Also I doubt they need to target the best possible chain bikes in order to be a viable solution.

Since it has a battery and the battery is (most likely) chargeable, a little loss of efficiency is inconsequential. On the other hand, having an actual physical chain on an electric bike seems indeed unnecessary - at least for less sporty applications, where things like "feel" or precise power delivery are not important. The end result will be a simpler, more reliable bike. Not to mention better looking.

I googled Schaeffer Free Drive efficiency.

A Tesla motor is 98.5% efficient, so a generator and motor combo being 93% efficient does not sound like a stretch.

You need to get your derailleurs adjusted. I bike almost every day and it never happens to me, even when I do inadvisable hard shifts.

Been there. If you're riding a 1x drivetrain, a narrow-wide chainring will greatly reduce chain drops. A conventional chainring is designed for the chain to be thrown off easily, and the front derailer keeps it there. On a 1x system, the ring can be designed differently.

Hey thanks for this. I realized one of my bikes has been built wrong since I got it 15 years ago due to this comment.

Not really a normal thing;tTake your bicycle to a bicycle shop for diagnosis and repair. It make take a follow-up visit. Sometimes issues around dropping chains can be a bit complex to diagnose.

It only happens once a season or less for me and is almost always due to adjustment problems. And 90% of the time I can get it back on without touching the chain by using the front or rear derailleur.

If you're riding a single speed bike and the chain regularly derails, then that definitely sounds like a chain tension or alignment problem.

If your chain isn't too badly fallen off, you can usually just shift in the opposite direction of where it fell off and the derailleur will usually get the chain back on without having to get your fingers greasy.

Be careful when you do this so as to not apply too much power when you're trying to do this. If you're in a really high gear and it happens, you can get off, hold your rear tire off the ground and turn the pedals. Works 90% of the time unless you got your rear chain jammed between the cassette and the spoke.

Edit: You can very often see this if you watch professional bike racing. When the mechanics change a rear tire it will almost always knock the chain off of the front chainring. They'll just shift into the proper direct (low if it's off the high side and high if it's off the low side) and then spin the cranks and the chain will come back on.

I've gone entire seasons of hard mountain biking and touring without having my chain come off. I think your bike might need an adjustment or maybe you have a worn chainring.

1. Check your limit screws. Park Tool has nice Youtube videos for adjusting these.

2. If it's the rear derailleur, it may be bent (especially if your limit screws from step 1 are maxed out). You need a derailleur alignment gauge (or just take it to a shop) to verify.

If it bothers you that much the solution is a belt drive, which is still more efficient than a generator.

Wait until your chain gets ransomware

It's really catastrophic when the drive chain's watchdog timer has to reset it because some function went awry.

Not a normal thing. My chain never goes out. Only on janky beater bikes it did. To the bike shop you go.

Tuck a pair of nitrile gloves under the saddle or into your toolkit. No greasy fingers.