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Comment by rapsacnz | Hacker News Reader

Pretty sure that this is not going to work very well - Time taken to heat a wire is probably slower than a servo motor. Energy taken to heat the wire is also likely to be more than that required by an electric motor. Also, this seems to be for a front 2 ring derailleur - which noone even uses anymore. If you tried to make this work for a modern rear derailleur, you'd need a lot of wire.

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On the contrary, 2x10 bike setups are getting more common these days even for MTB, all the manufacturers offer 2x10 setups.

One big advantage is that all combinations on a 2x10 are usable, whereas with a classic 3x9 you have to avoid being at high gear up front and low gear at the back, or you will be crossing the chain and damaging components / dropping chain.

I think they were referencing mountain bikes. They are nearly all 1x now.

.. and i still don't understand how we're all just supposed to ignore the monster chain crossing that this setup implies.

It doesn't seem to be much of a problem on my 1x mountain bike.

It's less crossing than 2x at the extremes

I run a 1x10, and there is no problem with chain crossing. The 10/11/12 speed cassettes are basically not any wider than the regular 9 speed ones, so there is no more chain crossing than what you get for the middle ring on a 3x9. The optimization is all in narrower chains and sprockets.

That being said, I do run an upper chain guide to reduce probability of the chain falling off the chainring when the rear derailleur gets clogged with mud etc.

The vast majority of road bikes sold today still have a front 2 ring derailleur. A few manufacturers do offer 1x drivetrain options but they aren't very popular because even with 12-speed sprockets there is a more limited range of gear ratios and a bigger jump between gears.

I wouldn't dismiss the idea so quickly. This appears to be a stepping stone to automatic gear shifting. Memory alloy would be cheaper and more reliable than step motors.

Electronic shifting is already a thing, and they make it work pretty well with servos.

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