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It still misses something basic for a commuter bike, a mudguard.

An urban or commuting bike without one makes no sense whatsoever.

It's a $50 add-on on their website.

Mudguards should be default for bikes. It's absurd that when it rains people ride bikes and walk around with a stripe of shite up their back and front b/c manufacturers are too cheap to include fenders (mudguards) on bikes.

The customers aren't much smarter of course - they bought the bike! Anyone fool enough to walk around (twice) looking like that deserves ridicule.

> customers aren't much smarter of course - they bought the bike

You seem to have undermined your argument for selling mid guards as a default.

> Anyone fool enough to walk around (twice) looking like that deserves ridicule

Whatever floats your boat.

Chances are, you can buy a bicycle that is 'made' by whatever your favourite car brand is.

Need a Ferrari bicycle? How about a Ford, a BMW, a Mercedes or anything else?

Chances are that there is a bicycle out there with your favourite car logo slapped on the headtube. And none of them have sold, maybe with the exception of Peugeot, but they got out of bicycles too (albeit to license the brand). Note that Peugeot and scores of other auto companies started with bicycles before adding motors and wheels, so bicycles should be a core competency.

As for Rivian and their bicycle, they will sell a few to people that just want the bed of their truck to have a bicycle in it. Non-Rivian truck owners? They will take a pass.

But as a 'halo product', it should work. They can get the marketing they want from it.

Efficiency here is the NFR that would be like: perfect is the enemy of good.

Think of this an electric bike with optional pedal assist from the human. Efficiency is irrelevant if the range is large enough.

I have a large battery, I ran short of power a couple of times in the past year. These batteries age and if you want to use their range to limit that aging, at some point you'll have to gamble. It's already bad enough to human power those heavy electric bikes, adding more drag doesn't sound fun.

>The whole "pedaling to load the battery" is both inefficient (you'll lose north of 70% of energy on the most efficient bike dynamos) and less reliable than having a direct link between your pedals and the wheel

Can't you still run it downhill and regain energy? A lot of downhills in the city can't utilize the gravity all the way, instead having red lights just at the bottom of the hill

> Can't you still run it downhill and regain energy?

That just means you had stored potential energy, otherwise how are you going to get up the hill?

I'm not sure what you mean? You need to get up the hill to get down the hill, but today when I do that the energy downhill gets wasted through heating of my brakes at the bottom. If I could use that energy for easier time the next hill around that'd be really nice.

On moderate descents a bike reaches equilibrium with the air resistance at a low speed, so there's nothing to recover.

Afaik almost all ebikes do not have regen. If it's a hub motor it's often geared with a one way bearing, and if it's mid drive (getting more popular) then you cant have regen as the chain is not back-drivable.

The efficiency gains of bicycle regen is not high enough and there is added drag of pulling a motor along if you are just pedalling normally. Most regard the trade-offs to be not worth it.

There is one Canadian ebike parts manufacturer that's pushing for regen, and their main reason for doing so is that it saves on brake pad wear.

There are some scooters with regen I think. At least I've seen scooter motor controllers with that option. I'm not sure if it's worth it. Maybe in hilly landscape.

I don't know if my ebike has regen or not, but if doesn't, it must be dumping that energy as heat somewhere. With the battery connected, the motor is breaking the bike. With the battery disconnected, the bike rolls as freely as a normal bike. It's very noticeable.

Yeah it’s just heat. Some e-bikes have a clutch to disengage the motor to prevent this motor breaking.

Wouldn't it be much simpler to disengage the battery electrically than a physical clutch? Or is the "clutch" just an electronic?

And where is the heat dumped? Why does the physical resistance disappear when the battery is disconnected?

I’ve had an ebike that had regen (Stromer ST2). It wouldn’t have any effect on the battery, but was great for savings life of your brake pads

I suspect that is correct. There just isn't that much available energy to recover in most bike stops. The point about brake pad wear however is more relevant than you might expect. Bike brakes can be surprisingly expensive and on my e-bike I went through a full set in only 700 miles.

Of course there is the minor problem that the hub was mounted in the rear wheel so it's only good for gentle to moderate braking, but thankfully that is the vast majority of what you do.

Electric generator->battery->electric motor drive train should be fairly efficient. I'd be surprised if it was lower than 80%.

Traditional dynamos are fairly small parasitic loads and not really comparable.

Normal bicycle drivetrains have efficiencies around 95%...

Haven't there been studies showing that a bicycle is the most efficient form of movement available?

Thats called a series hybrid and it kinda sucks. Motors only reach high efficiency at high loads, and you have 2 of them between the feet and wheel. That configuration is bad when the battery dies because you will feel that inefficiency.

> I'd be surprised if it was lower than 80%.

80% is really bad for a bicycle. A well-maintained bicycle drive chain is basically 100% efficient.

Dynamo is the general term for electric generators from mechanical displacement. I'm not talking about the small contraptions that power lights on a bike, these are traditionally even worse in efficiency.

Lets be charitable and call it 90%, it's still going to charge the battery (which is described as a buffer), and that will have a max of 95%, discharge the battery, same, and power the motor, which has likely the same efficiency. You're at. 9.95.95*.9 = 73% efficiency at motor output. You're giving 27% to the gods of thermodynamics, unless you like the extra complex cardio you're getting, I don't really see the point. Regular bike transmissions are not free either, but they're closer to 95%.

Thinking about all that, I don't get why they didn't use a hub motor. Why adding a belt when you could have transmitted the power directly to the wheel?

Your original post says 70% loss, i.e. 30% efficiency. In the context of an e-bike, to me, 70% efficiency is fine. It's a large bike and the majority of the power for the majority of users is likely going to be coming from the battery anyways.

Also presumably we should be comparing the efficiency to other ebikes not traditional bikes. I'm not sure how effective traditional ebikes are at integrating motor + human power together but I'd imagine there are some additional losses.

I'm assuming the thought process behind the pedal->generator->traction motor is that you can keep the cadence in the ideal / most efficient range. Problem with mid drives is that (at least for me), I prefer lower cadence which means driving the hub drive at a less efficient range.

I don't hate it, but I'm curious to see what they think their target audience is.

Is it someone that wants to do a "last mile" from their car/train to office? Is it a car replacement? Is it a weekend farmers market family bike?

I feel like all of these require emphasis on different aspects. If it's a last mile commuter, it needs to be light / small so it can fit on a train or car trunk. Probably also needs to be light so it's luggable into/out of the trunk by an average person.

I guess for me, the most interesting ebike idea is that of a "last mile(s)". Something that I can easily pack in the trunk, and depending on my mood, allow me to park ~5-7 miles from work and cycle the rest of the way in. There are bits of my commute near my office that are often at a standstill, and ebiking would be significantly faster to skip those. This is much less of a commitment compared to doing the entire 20mi commute by bike.