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Rivian's TM-B electric bike

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190 points hasheddan | 5 comments | 22 Oct 25 18:00 UTC | HN request time: 0s | source
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justinator ◴[22 Oct 25 23:08 UTC] No.45676303[source]▶
Pedaling to make energy to store in a battery that then runs an electric motor seems to get around the best thing about bicycles: their efficiency.

No one is going to do that. It's an electric motorcycle in disguise. Don't even play.

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dfltr ◴[22 Oct 25 23:18 UTC] No.45676373[source]▶
If only there were some way to take all that work of pedaling and efficiently translate it into torque on the rear wheel, right?
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justinator ◴[22 Oct 25 23:44 UTC] No.45676570[source]▶
like a... drive train or something?

science fiction my good dude.

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1. _whiteCaps_ ◴[23 Oct 25 02:22 UTC] No.45677486[source]▶
Wouldn't you be able to pedal at your most efficient rate, and go at whatever speed you want? Like how diesel-electric trains don't actually drive the wheels with the diesel engine, they power an electric motor.

(I've never ridden any kind of e-bike so I don't really know how it works)

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2. pandaman ◴[23 Oct 25 03:23 UTC] No.45677846[source]▶
Trains and large trucks use this setup because a mechanical gearbox would need to be enormous to withstand torques they produce. Bikes don't experience even moderate torques so they can be equipped with 10-20 geared transmissions, which weight under 1 kg.
3. justinator ◴[23 Oct 25 03:26 UTC] No.45677862[source]▶
Bikes have very efficient transmission systems, so outside of extremes you can pedal at an efficient amount of torque for the rider regardless of say: hitting a big hill. This is doubly so for e-bikes that assist in the pedaling.

This is more akin to a hybrid car, who's gas engine could generate electricity, but in the case of this e-Bike from Rivian, why would you do that? The electric motor is significantly more powerful than a person's legs, outside of the Pro Peleton.

Watch anyone on a Class 3 ebike: they're not pedaling. The bicycle drivetrain is just there to get around regulations, like having a license.

Rivian isn't known for making hyper-efficient electric vehicles. Rivians are MANLY trucks made to do MANLY truck things, like go fast! and go through tires faster!

4. DangitBobby ◴[23 Oct 25 04:49 UTC] No.45678250[source]▶
This is called a "digital" bike.

https://www.ebike24.com/blog/digital-drive-ebikes

5. aidenn0 ◴[23 Oct 25 05:40 UTC] No.45678497[source]▶
On my e-bike, with just a standard 7-speed transmission I can pedal at my most efficient rate always; since I have an extra 300W of power available I don't need the super-low gears for climbing.