Torque isn't the only consideration, there's also efficiency and acceleration. Transmission aren't a necessity like they are in ICE cars, but they can improve the experience.

For instance the Porsche Taycan:

"Having a multispeed transmission in an EV provides the same benefits that it does in a gasoline-powered car: improved low-speed acceleration and increased efficiency at high velocity by lowering the rotating speed of the power source."

https://www.caranddriver.com/news/a28903274/porsche-taycan-t...

That's also the point to the transmission. A transmission (on the low end) is to enhance acceleration and efficiency (keeping you at an ideal ratio to maintain the speed you're going). Neither of these are issues when you have a flatter torque curve.

Another comment said the efficiency gain on the Taycan is 5% over not having it. Which is about what I would've expected to see, not much for all the added complexity and reliability issues it introduces.

Electric motors draw more current when starting up and when delivering high torque. It's conceivable that with a transmission, maximum current draw could be lowered, perhaps leading to longer-lived batteries or lower demand for battery cooling, smaller gauge wiring, smaller motors, or other cost savings. Don't know for sure on any of this, but it seems plausible. On the other hand, if it really made a difference, why aren't the EV makers already doing it?

A more complicated gearbox means more friction which lowers the fuel efficiency of the vehicle. Since the battery is the most expensive part of a BEV, maximizing fuel efficiency is always a priority. It determines the cost and the range for the car.

EVs with multiple gear ratios do exist though, the first of which was the 2020 Porsche Taycan. The first gear lets it maximize torque at low speeds (up to 62 MPH) so it can set 0-60 records, then the second gear lets it maintain a more economical motor speed for highway driving.

I remember reading somewhere that the estimated efficiency gain of having 2 gears on the Taycan is 5%. On a typical 60kWh battery car, that's 3kWh... hardly worth the effort nor the cost. On the Taycan it makes sense because top speed. For any "normal" EV where top speed is not a concern, it's probably not a choice that makes sense.

Also people who buy manual transmissions in preference to autos rarely give a fuck about economy (this is my opinion and about every manual transmission aficionado I have ever spoken to)

There was a time when manual transmissions were alleged to give better fuel economy than automatics, but I think that's long gone now.

I suspect it makes a big difference in range at higher speeds that Germans and Americans drive at on the highway. One of the most disappointing things about the Model3 is how quickly the range starts to dip at left lane traffic speeds here in the Northeast. There’s large stretches of the drive between NYC and Boston that have middle and left lane traffic moving at 80 MPH and what’s an easy task for a gas car means adding a recharge stop for anything except the Model3 Long Range.

Constant speeds on the highway should be the most efficient forms of driving. The only force the motors need to generate is the force required to overcome air resistance, this is going to be true of both ICE and electric.

The range dip may instead be because of lower battery temperatures (from all of the wind). Better battery thermal management at high speeds might help.

Higher energy density batteries will also comfortably overcome this problem. In the future I can see EV's that advertise fixed ranges, so that you don't get arbitrary range dips. They'll do this by over dimensioning the batteries and using better battery management software to make sure that more than 95-99% of your drives will be able to go at least the advertised range

To the contrary, the dip in range highlights that, as you increase speed, air resistance rises as a square.

Our Leaf could probably go almost 50% farther on a charge if we never exceeded 30 mph. 30-40 mph has a small penalty; freeway speeds exact a much larger penalty.

It increases as the square of air resistance compared to traveling at low but constant speeds.

But I find that when I'm driving at lower speeds I'm constantly stopping and starting for traffic.

Around where I live there are many roads posted at 80km/h (50mph) with traffic lights every km or so. So it's accelerate to 80 for a couple minutes, then come to a complete stop, then accelerate back to 80. That's clearly what swallows up most of the range.

Wind resistance increases with the square of speed so going faster than “normal” speed, i.e. the speed they use when calculating range, leads to dramatically less range.

> Electric motors don’t need manual (or indeed, any) transmissions because they have a basically-flat torque curve across their entire RPM range.

I would argue that for an EV that is not designed to be a sports car (ie, a Model 3), you are correct.

But one that is being designed to not just have power off the line, but also at the top end, will probably need a transmission.

I do wonder if the top speed of my Model 3 Performance is due to simply not having enough power to overcome drag, or if the motors are reaching the end of their RPM range.

Teslas actually do have different gearing ratios, in that for the dual motor cars the motors in the front and rear are geared differently. This is a cheap, effective way to get a good combination of acceleration and efficiency.

They do have transmission. I checked it a year ago because I thought they don't.

But it's fixed.

Three cylinder engines have a flat torque curve. They still benefit from a transmission.

You're just thinking of small turbocharged engines, which always had a flattish torque curve if the turbo was tiny.

(street triple checking in) mostly flat.