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> They could even do a stickshift EV if they wanted to, though most car companies seem to not think it's worth the complexity/maintenance, and I get the impress

> They could even do a stickshift EV if they wanted to, though most car companies seem to not think it's worth the complexity/maintenance, and I get the impression that electric motors are hard on transmissions. Electric motors have a wider power band, so there’s less need for gear shifting. They could get more efficiency with multiple gears, but it’s be a smaller benefit than in an ICE vehicle. One of the big early problems was that the amount of instant torque that an electric vehicle puts out just shreds a gearbox. You could limit the initial torque in software, but that’d kill the joy of the EV. I’m sure someone has managed to work this by now. On the other hand, different axles don’t have to use the same gearing ratio. That’s how dual motor Teslas work - the front wheels are geared for higher speeds, and more power is shifted towards those as you go faster. No gear-shifting required.

abfan1127 6y ago
is there some type of clutch that allows the rear wheels to free-spin at higher speeds?
- stetrain 6y ago
  On Tesla cars both motors are physically connected to the gearbox/axles with no clutch. They are doing careful tuning of the motor inverter controls to minimize energy use from motors that aren't under active load. Tesla refers to this as "Torque Sleep" I imagine the process is basically tuning for the inverter output that minimizes power consumed as well as drag on the axle when the motor is not supplying active torque, or at least supplying less active torque than the other axle.
  - mrfusion 6y ago
    Offtopic but you seem to know a lot. I’ve been wondering do Tesla’s just have one regenerative braking force when you let off the gas? Doesn’t this leave a lot on the table? Wouldn’t you get more energy by having say gentle braking regen and harder braking regen?
    - deleted 6y ago
      [deleted]
    - stetrain 6y ago
      You have analog control over the regen braking with the accelerator pedal. Push down to accelerate, lift up a little to maintain current speed, lift up a little more to start slowing down, lift off all the way for maximum regen. It takes a week or two to unlearn the habit of "popping" your foot off the accelerator anytime you want to coast without necessarily slowing down, but after that it basically feels like your right foot is directly connected to the speedometer in both directions.
      - brianwawok 6y ago
        If you judge distances well you can still pop your foot. The deceleration curve is optimized to be smooth (minimize jerk?).
        chemmail 6y ago
        After a week you can judge pretty well. I use my brake pedal maybe once a week nowdays unless i'm driving alone and wanna feel some Gs.
        mrfusion 6y ago
        Is it hard to switch back and forth between a normal car after that?
        WorldMaker 6y ago
        Hard? No. Irritating? Not surprisingly. I've had ICE loaners when my car is in for repair, and missing "one pedal driving" happens a lot, but it doesn't stop me from operating the ICE vehicle. Perhaps weirdly the thing I think it makes the hardest is possibly videogames, which exaggerate controls in their own ways. I've gotten very frustrated with braking in most difficulty settings in the Forza series after driving an EV with "one pedal driving" capability for years now.
- piva00 6y ago
  Don't know about the Teslas but the Porsche Taycan does exactly that but for energy saving.
- saberdancer 6y ago
  Haldex type of 4 wheel drive do this, but in that case the rear wheels are disconnected at most times, they are engaged only when the car feels the need (hard acceleration, etc). It's not a big deal. In EV cars it is more complicated as they usually have an engine per wheel so you'd need a clutch at each wheel.
cure 6y ago
> On the other hand, different axles don’t have to use the same gearing ratio. That’s how dual motor Teslas work - the front wheels are geared for higher speeds, and more power is shifted towards those as you go faster. No gear-shifting required. Yep. Alternatively, the Porsche Taycan has an 2-speed transmission gearbox (cf. https://www.caranddriver.com/news/a28903274/porsche-taycan-transmission/ https://www.caranddriver.com/news/a28903274/porsche-taycan-t...). I don't think gearboxes are going to become mainstream in EVs, with the exception of performance vehicles like this one.
- mrfusion 6y ago
  Do the Tesla’s still have differentials then? It would be cool to eliminate those two but then you’d need a motor for each wheel I guess.
  - Negitivefrags 6y ago
    They do for all the models currently on the road. In the future the Roadster and the Cybertruck both have 3 motors. The rear wheels both have one each, so presumably they can avoid the differential there.
  - chaboud 6y ago
    Rivian has an independent 4-motor setup. It's a compelling case of extra parts allowing for simplicity. It also allows for the ever-entertaining tank turn: https://www.youtube.com/watch?v=yzwM8KE2L3I https://www.youtube.com/watch?v=yzwM8KE2L3I
  - sandworm101 6y ago
    Differentials still have a place. They allow wheels to be perfectly balanced when negotiating corners. That can be done with independent electric motors, but never perfectly. Lot of little factors have to be considered in the software. For instance, as a car corners weight shifts, this causes the diameters of pneumatic tires to change slightly. A mechanical differential handles this tiny effect seamlessly. Independent motors on each wheel would have to sense, calculate and react to this via software. That is just one effect. There are also uneven road surfaces to deal with. Any slight error would result in one wheel dragging or trying to accelerate, resulting in instability or at least chewing through tire rubber. Differentials are cheap and reliable, most going for the lifetime of a car without any issue or even real servicing. They are likely the cheaper option than running multiple motors.
samstave 6y ago
It would be cool to have a stick-shift in the car that was fake, and would just make the car play different sounds as you "shifted" and allow you to control your playlist and volume levels with it...
- Animats 6y ago
  Somebody put that in an early electric performance car. You actually had to shift, and got audio effects, but it was just software emulating gears. It was laughed at in the automotive press.
  - saberdancer 6y ago
    People don't like fake.
    - deleted 6y ago
      [deleted]
    - ben_w 6y ago
      Sure we do, we just don’t like bad fakes. (Bad is subjective, but the point remains)
detaro 6y ago
I wouldn't be surprised if at some point some manufacturer made a car with optional "stick shift" - with a stick that's just some switches and the effect on driving behavior/torque/... entirely done in software. (Right now electric is hot and new, so nobody is doing much to make an electric car pretend to be something it's not, but that could switch around when electric is the standard)
- gambiting 6y ago
  There is a car exactly like this....in China. It's used for driver training, and I suspect it will start being popular elsewhere. In all of EU if you pass your licence on an automatic(which nearly all electric cars are) you can't drive a manual, you have to pass your licence in a manual car. And that's why that car was created, to allow people to pass their test in a manual vehicle and have a licence that allows driving them, even though the vehicle is electric. https://jalopnik.com/this-chinese-electric-car-designed-for-driving-schools-1844071179 https://jalopnik.com/this-chinese-electric-car-designed-for-... "The various inputs of clutch and shifter work with software in the car that cause it to behave like a manual, ICE car, with shift points, simulated engine sounds, and it can even “stall” if you let off the clutch too quickly."
  - alasdair_ 6y ago
    Part of me wants to create a fake gearbox and clutch kit for an automatic car that does absolutely nothing, but looks convincing to driving examiners. You can just change "gears" when you feel like it without any actual effect and the clutch is just a dumb pedal.
    - ThePadawan 6y ago
      > and the clutch is just a dumb pedal Thus completely negating training on a manual? Learning how to effectively use the clutch pedal to me was like, 90% of learning to drive.
    - jusssi 6y ago
      Accelerating to a highway would be a dead giveaway to an examiner. Those who learn to use the clutch well enough in the mandatory 20 hours to do it as smooth as automatic gear are few and far between. And obviously they are the ones who wouldn't need to fake it anyway.
mtw 6y ago
> instant torque that an electric vehicle puts out just shreds a gearbox Doesn't the Porsche Taycan have 2 gears? and it actually beats Tesla Model S in 0-60 times
- brianwawok 6y ago
  Plaid S is due this year to take back the crown. Curious if it adds a gear or just bigger motors.
  - alasdair_ 6y ago
    Model model S (okay, any dual motor version) have different gearing on the front and rear wheels, so that more power can be sent to the front as speeds increase.
- alasdair_ 6y ago
  Roadster is due out this year with a 1.9s 0-60 (and an 8.9s quarter mile). Can anyone here lend me a quarter million please?
mrfusion 6y ago
Doesn’t the taycan have some kind of gears?
- elihu 6y ago
  I think so.
throwaway0a5e 6y ago
For anything that isn't a car you're gonna want gears for the same reason electric drills have gears. Think of it like low range. "muh instant 0rpm torque" is absolutely nothing compared to the inertia of a hired driver who doesn't care (or is just a novice) dumping the clutch. Building a transmission to handle electric motor loads isn't a particularly remarkable engineering challenge. (Though you can make any engineering exercise challenging if you add sufficient weight and budgetary constraints) Imagine a medium or heavier truck that's expected to both get a load moving at low speed and to cruise at 80. Putting anything near peak power through an electric motor at low speeds lets the magic smoke out in short order. Sure you can gear it down but then you have insane rpm at high speed and the wonderful engineering problem of getting that insanely overbuilt motor to not fling itself apart at those speed. A simple two speed transmission is a far more elegant solution. Especially since a transmission for an electric motor can be far simpler than one for an ICE. Letting the magic smoke out was a big problem in early EV conversions because power was low and consequently the vehicles available for conversion didn't have lots of good options for deep gearing.
- gwbas1c 6y ago
  I've done both. Clutch dumps require that you rev the engine up to high RPMs first. Instant torque is, well, instant. I suggest you try it before you make fun of it.
  - throwaway0a5e 6y ago
    Oh I know that a clutch dump is a far less elegant way to get moving than having torque available at 0rpm but the former is far, far harder on things. The point I'm trying to make is that the people acting like electric motors are particularly hard on drive-line components are just wrong.
- bdamm 6y ago
  Avoiding overheat conditions is something the vehicle engineering needs to deal with. Teslas solve this problem with liquid cooling and the motor controllers use temperature sensors in the motor core to determine if the currents are too great for the cooling. So really, no issue. I expect the Tesla Semi will handle heavy loads at low speeds just fine. As for clutch dumping, I'll take electronic stability and traction control over the smell of burning clutch any day. Plus, the traction delivery is better in an EV; much less rotating mass means more rapid response and a better grip on the road.
kingkawn 6y ago
Program it like a video game stick shift, let the software do the shifting
dehrmann 6y ago
Don't diesel-electric locomotives use transformers for gear shifting? I assume if it's even needed for electric cars, they'd use something like that.
chemmail 6y ago
Porche Taycan has two speed transmission and Bosch has a turnkey 2 speed for EV applications. But seeing the numbers the Taycan puts down show it isn't a humongous difference like in an ICE. Probably not worth the cost/complexity as we see the Lucid Air can do qtr mile times in less than 10 seconds and soon upcoming Plaid Model S will have a possible quarter mile time of under 9 seconds and 200mph top speed.
- alasdair_ 6y ago
  The roadster is supposed to clock at 8.9s quarter mile and 250+ MPH at a minimum. We'll see if they actually deliver. As for top speed - I think the main issue with earlier gen tesla model S issues was that the speed was capped in software at 155MPH, even for the "P" models. There wasn't really any reason other than liability/testing that they couldn't go faster (700+ horsepower and ridiculous drag coefficients would imply that the real peak would be higher).
  - elihu 6y ago
    At some point you'd hit the maximum safe RPM limit of the motor. Tesla tends to use motors that can run at very high RPMs, but eventually centrifugal force would damage or destroy it. Also the bearings might wear out. I don't know if the software limit is set to match the RPM limit of the motor, but it makes sense that they would. Also, AC motors tend to lose power and efficiency if they're pushed beyond their optimal range. If Teslas are already at the RPM limit, they could get a higher top speed by changing the gear ratios, but then you'd have less power at low speed. Since hardly anyone actually drives at 155MPH, it's sensible to optimize for the way the cars will actually be used almost all of the time.
saberdancer 6y ago
I'm not sure of the power curve for an electric vehicle, but if you add gearing, you introduce losses due to gearbox and you increase complexity. It's likely that it is not worth it in most applications. Only cars that used gearboxes in EV space (two speed) are usually intended to be able to hit 200mph so they need extremely wide rpm range from their electric motors. I know Rimac used one and Taycan (not surprising since Rimac is partly owned by Porsche). In Rimac case, they used the gearbox to improve 0-60 times but IIRC they are losing the gearbox for their new car.
- VLM 6y ago
  Hybrids often use gearboxes. My wife's Prius was essentially an extremely heavy 70 HP equivalent EV. 0 to 10 it was a very fastest car although the acceleration curve flattened out fast and it was between hard and impossible to have enough traction to max it out. I don't hear much about prius transmissions being destroyed. Something interesting to think about, I wonder with demographic trends etc if 0 to 10 is a more useful measure of daily driver performance and experience than 0 to 60. My wife's car does 0 to 10 at every stop sign, and technically my car is faster at 0 to 60 but I only did that twice a day at most for the commute, for sportiness reasons I might prefer the worlds fastest 0 to 10 car over a theoretically faster 0 to 60 car.
  - throwaway0a5e 6y ago
    >something interesting to think about, I wonder with demographic trends etc if 0 to 10 is a more useful measure of daily driver performance and experience than 0 to 60. My wife's car does 0 to 10 at every stop sign, and technically my car is faster at 0 to 60 but I only did that twice a day at most for the commute, for sportiness reasons I might prefer the worlds fastest 0 to 10 car over a theoretically faster 0 to 60 car. Depends on how long the average on-ramp where you live is. 30-75 measured in distance instead of time would be a good measure where I live. Being able to gracefully merge no matter how bad of a situation the idiot in front of me leaves behind would be far more beneficial for day to day use than off the line speed.
  - supermatt 6y ago
sandworm101 6y ago
>> You could limit the initial torque in software, but that’d kill the joy of the EV. All electric cars are torque-limited. They simply have to be. A static electric motor, of the type needed for higher speeds, given full voltage would not only snap bits of the drivetrain but rip apart its own mounts. So they are all limited to various degrees. The limiting factor on low-speed power for EVs isn't the motor. It's the strength of the drivetrain and ability of the battery system to provide the necessary current/voltage without cooking something.
- luma 6y ago
  Is this still true with the use of SynRM motors (as deployed by Tesla)?
  - sandworm101 6y ago
    All electric motors boil down to magnets pulling and pushing on each other to make movement. Whether the torque protection is via software, circuitry, or mechanical wizardry doesn't really matter. They all need it somewhere to prevent static magnetic forces from pulling everything else apart.
- throwaway0a5e 6y ago
  >All electric cars are torque-limited. They simply have to be. A static electric motor, of the type needed for higher speeds, given full voltage would not only snap bits of the drivetrain but rip apart its own mounts. So they are all limited to various degrees. Electric motors are far, far, more forgiving to drive-train components than sporty vehicles with manuals and medium duty trucks of equivalent power levels because there is no clutch to dump. Sure it's not quite as forgiving as an automatic transmission but it's close.
  - sandworm101 6y ago
    No. Electric motors are potential torque beasts. That is why they, ALL of them in cars, are mated to motor controllers. The controller may be integrated into the motor assembly so as to give the impression that the motor is tame, but the reality is that every electric motor has the potential for damaging/dangerous levels of torque. https://en.wikipedia.org/wiki/Motor_controller https://en.wikipedia.org/wiki/Motor_controller "A motor controller is a device or group of devices that can coordinate in a predetermined manner the performance of an electric motor. [...] regulating or limiting the torque, and protecting against overloads..."
Mauricebranagh 6y ago
I think top gear did this when they staged a drag race between the original Tesla and its Donor car. The amount of torque and electric vehicle can put out is huge.
baybal2 6y ago
> instant torque that an electric vehicle puts out just shreds a gearbox. On other hand, you can put way more beefier gears, as you need less of them.

abfan1127 6y ago

is there some type of clutch that allows the rear wheels to free-spin at higher speeds?

stetrain 6y ago
On Tesla cars both motors are physically connected to the gearbox/axles with no clutch. They are doing careful tuning of the motor inverter controls to minimize energy use from motors that aren't under active load. Tesla refers to this as "Torque Sleep" I imagine the process is basically tuning for the inverter output that minimizes power consumed as well as drag on the axle when the motor is not supplying active torque, or at least supplying less active torque than the other axle.
- mrfusion 6y ago
  Offtopic but you seem to know a lot. I’ve been wondering do Tesla’s just have one regenerative braking force when you let off the gas? Doesn’t this leave a lot on the table? Wouldn’t you get more energy by having say gentle braking regen and harder braking regen?
  - deleted 6y ago
    [deleted]
  - stetrain 6y ago
    You have analog control over the regen braking with the accelerator pedal. Push down to accelerate, lift up a little to maintain current speed, lift up a little more to start slowing down, lift off all the way for maximum regen. It takes a week or two to unlearn the habit of "popping" your foot off the accelerator anytime you want to coast without necessarily slowing down, but after that it basically feels like your right foot is directly connected to the speedometer in both directions.
    - brianwawok 6y ago
      If you judge distances well you can still pop your foot. The deceleration curve is optimized to be smooth (minimize jerk?).
      - chemmail 6y ago
        After a week you can judge pretty well. I use my brake pedal maybe once a week nowdays unless i'm driving alone and wanna feel some Gs.
        mrfusion 6y ago
        Is it hard to switch back and forth between a normal car after that?
        WorldMaker 6y ago
        Hard? No. Irritating? Not surprisingly. I've had ICE loaners when my car is in for repair, and missing "one pedal driving" happens a lot, but it doesn't stop me from operating the ICE vehicle. Perhaps weirdly the thing I think it makes the hardest is possibly videogames, which exaggerate controls in their own ways. I've gotten very frustrated with braking in most difficulty settings in the Forza series after driving an EV with "one pedal driving" capability for years now.
piva00 6y ago
Don't know about the Teslas but the Porsche Taycan does exactly that but for energy saving.
saberdancer 6y ago
Haldex type of 4 wheel drive do this, but in that case the rear wheels are disconnected at most times, they are engaged only when the car feels the need (hard acceleration, etc). It's not a big deal. In EV cars it is more complicated as they usually have an engine per wheel so you'd need a clutch at each wheel.

cure 6y ago

> On the other hand, different axles don’t have to use the same gearing ratio. That’s how dual motor Teslas work - the front wheels are geared for higher speeds, and more power is shifted towards those as you go faster. No gear-shifting required. Yep. Alternatively, the Porsche Taycan has an 2-speed transmission gearbox (cf. https://www.caranddriver.com/news/a28903274/porsche-taycan-transmission/ https://www.caranddriver.com/news/a28903274/porsche-taycan-t...). I don't think gearboxes are going to become mainstream in EVs, with the exception of performance vehicles like this one.

mrfusion 6y ago
Do the Tesla’s still have differentials then? It would be cool to eliminate those two but then you’d need a motor for each wheel I guess.
- Negitivefrags 6y ago
  They do for all the models currently on the road. In the future the Roadster and the Cybertruck both have 3 motors. The rear wheels both have one each, so presumably they can avoid the differential there.
- chaboud 6y ago
  Rivian has an independent 4-motor setup. It's a compelling case of extra parts allowing for simplicity. It also allows for the ever-entertaining tank turn: https://www.youtube.com/watch?v=yzwM8KE2L3I https://www.youtube.com/watch?v=yzwM8KE2L3I
- sandworm101 6y ago
  Differentials still have a place. They allow wheels to be perfectly balanced when negotiating corners. That can be done with independent electric motors, but never perfectly. Lot of little factors have to be considered in the software. For instance, as a car corners weight shifts, this causes the diameters of pneumatic tires to change slightly. A mechanical differential handles this tiny effect seamlessly. Independent motors on each wheel would have to sense, calculate and react to this via software. That is just one effect. There are also uneven road surfaces to deal with. Any slight error would result in one wheel dragging or trying to accelerate, resulting in instability or at least chewing through tire rubber. Differentials are cheap and reliable, most going for the lifetime of a car without any issue or even real servicing. They are likely the cheaper option than running multiple motors.

samstave 6y ago

It would be cool to have a stick-shift in the car that was fake, and would just make the car play different sounds as you "shifted" and allow you to control your playlist and volume levels with it...

Animats 6y ago
Somebody put that in an early electric performance car. You actually had to shift, and got audio effects, but it was just software emulating gears. It was laughed at in the automotive press.
- saberdancer 6y ago
  People don't like fake.
  - deleted 6y ago
    [deleted]
  - ben_w 6y ago
    Sure we do, we just don’t like bad fakes. (Bad is subjective, but the point remains)

detaro 6y ago

I wouldn't be surprised if at some point some manufacturer made a car with optional "stick shift" - with a stick that's just some switches and the effect on driving behavior/torque/... entirely done in software. (Right now electric is hot and new, so nobody is doing much to make an electric car pretend to be something it's not, but that could switch around when electric is the standard)

gambiting 6y ago
There is a car exactly like this....in China. It's used for driver training, and I suspect it will start being popular elsewhere. In all of EU if you pass your licence on an automatic(which nearly all electric cars are) you can't drive a manual, you have to pass your licence in a manual car. And that's why that car was created, to allow people to pass their test in a manual vehicle and have a licence that allows driving them, even though the vehicle is electric. https://jalopnik.com/this-chinese-electric-car-designed-for-driving-schools-1844071179 https://jalopnik.com/this-chinese-electric-car-designed-for-... "The various inputs of clutch and shifter work with software in the car that cause it to behave like a manual, ICE car, with shift points, simulated engine sounds, and it can even “stall” if you let off the clutch too quickly."
- alasdair_ 6y ago
  Part of me wants to create a fake gearbox and clutch kit for an automatic car that does absolutely nothing, but looks convincing to driving examiners. You can just change "gears" when you feel like it without any actual effect and the clutch is just a dumb pedal.
  - ThePadawan 6y ago
    > and the clutch is just a dumb pedal Thus completely negating training on a manual? Learning how to effectively use the clutch pedal to me was like, 90% of learning to drive.
  - jusssi 6y ago
    Accelerating to a highway would be a dead giveaway to an examiner. Those who learn to use the clutch well enough in the mandatory 20 hours to do it as smooth as automatic gear are few and far between. And obviously they are the ones who wouldn't need to fake it anyway.

mtw 6y ago

> instant torque that an electric vehicle puts out just shreds a gearbox Doesn't the Porsche Taycan have 2 gears? and it actually beats Tesla Model S in 0-60 times

brianwawok 6y ago
Plaid S is due this year to take back the crown. Curious if it adds a gear or just bigger motors.
- alasdair_ 6y ago
  Model model S (okay, any dual motor version) have different gearing on the front and rear wheels, so that more power can be sent to the front as speeds increase.
alasdair_ 6y ago
Roadster is due out this year with a 1.9s 0-60 (and an 8.9s quarter mile). Can anyone here lend me a quarter million please?

mrfusion 6y ago

Doesn’t the taycan have some kind of gears?

elihu 6y ago
I think so.

throwaway0a5e 6y ago

For anything that isn't a car you're gonna want gears for the same reason electric drills have gears. Think of it like low range. "muh instant 0rpm torque" is absolutely nothing compared to the inertia of a hired driver who doesn't care (or is just a novice) dumping the clutch. Building a transmission to handle electric motor loads isn't a particularly remarkable engineering challenge. (Though you can make any engineering exercise challenging if you add sufficient weight and budgetary constraints) Imagine a medium or heavier truck that's expected to both get a load moving at low speed and to cruise at 80. Putting anything near peak power through an electric motor at low speeds lets the magic smoke out in short order. Sure you can gear it down but then you have insane rpm at high speed and the wonderful engineering problem of getting that insanely overbuilt motor to not fling itself apart at those speed. A simple two speed transmission is a far more elegant solution. Especially since a transmission for an electric motor can be far simpler than one for an ICE. Letting the magic smoke out was a big problem in early EV conversions because power was low and consequently the vehicles available for conversion didn't have lots of good options for deep gearing.

gwbas1c 6y ago
I've done both. Clutch dumps require that you rev the engine up to high RPMs first. Instant torque is, well, instant. I suggest you try it before you make fun of it.
- throwaway0a5e 6y ago
  Oh I know that a clutch dump is a far less elegant way to get moving than having torque available at 0rpm but the former is far, far harder on things. The point I'm trying to make is that the people acting like electric motors are particularly hard on drive-line components are just wrong.
bdamm 6y ago
Avoiding overheat conditions is something the vehicle engineering needs to deal with. Teslas solve this problem with liquid cooling and the motor controllers use temperature sensors in the motor core to determine if the currents are too great for the cooling. So really, no issue. I expect the Tesla Semi will handle heavy loads at low speeds just fine. As for clutch dumping, I'll take electronic stability and traction control over the smell of burning clutch any day. Plus, the traction delivery is better in an EV; much less rotating mass means more rapid response and a better grip on the road.

kingkawn 6y ago

Program it like a video game stick shift, let the software do the shifting

dehrmann 6y ago

Don't diesel-electric locomotives use transformers for gear shifting? I assume if it's even needed for electric cars, they'd use something like that.

chemmail 6y ago

Porche Taycan has two speed transmission and Bosch has a turnkey 2 speed for EV applications. But seeing the numbers the Taycan puts down show it isn't a humongous difference like in an ICE. Probably not worth the cost/complexity as we see the Lucid Air can do qtr mile times in less than 10 seconds and soon upcoming Plaid Model S will have a possible quarter mile time of under 9 seconds and 200mph top speed.

alasdair_ 6y ago
The roadster is supposed to clock at 8.9s quarter mile and 250+ MPH at a minimum. We'll see if they actually deliver. As for top speed - I think the main issue with earlier gen tesla model S issues was that the speed was capped in software at 155MPH, even for the "P" models. There wasn't really any reason other than liability/testing that they couldn't go faster (700+ horsepower and ridiculous drag coefficients would imply that the real peak would be higher).
- elihu 6y ago
  At some point you'd hit the maximum safe RPM limit of the motor. Tesla tends to use motors that can run at very high RPMs, but eventually centrifugal force would damage or destroy it. Also the bearings might wear out. I don't know if the software limit is set to match the RPM limit of the motor, but it makes sense that they would. Also, AC motors tend to lose power and efficiency if they're pushed beyond their optimal range. If Teslas are already at the RPM limit, they could get a higher top speed by changing the gear ratios, but then you'd have less power at low speed. Since hardly anyone actually drives at 155MPH, it's sensible to optimize for the way the cars will actually be used almost all of the time.

saberdancer 6y ago

I'm not sure of the power curve for an electric vehicle, but if you add gearing, you introduce losses due to gearbox and you increase complexity. It's likely that it is not worth it in most applications. Only cars that used gearboxes in EV space (two speed) are usually intended to be able to hit 200mph so they need extremely wide rpm range from their electric motors. I know Rimac used one and Taycan (not surprising since Rimac is partly owned by Porsche). In Rimac case, they used the gearbox to improve 0-60 times but IIRC they are losing the gearbox for their new car.

VLM 6y ago
Hybrids often use gearboxes. My wife's Prius was essentially an extremely heavy 70 HP equivalent EV. 0 to 10 it was a very fastest car although the acceleration curve flattened out fast and it was between hard and impossible to have enough traction to max it out. I don't hear much about prius transmissions being destroyed. Something interesting to think about, I wonder with demographic trends etc if 0 to 10 is a more useful measure of daily driver performance and experience than 0 to 60. My wife's car does 0 to 10 at every stop sign, and technically my car is faster at 0 to 60 but I only did that twice a day at most for the commute, for sportiness reasons I might prefer the worlds fastest 0 to 10 car over a theoretically faster 0 to 60 car.
- throwaway0a5e 6y ago
  >something interesting to think about, I wonder with demographic trends etc if 0 to 10 is a more useful measure of daily driver performance and experience than 0 to 60. My wife's car does 0 to 10 at every stop sign, and technically my car is faster at 0 to 60 but I only did that twice a day at most for the commute, for sportiness reasons I might prefer the worlds fastest 0 to 10 car over a theoretically faster 0 to 60 car. Depends on how long the average on-ramp where you live is. 30-75 measured in distance instead of time would be a good measure where I live. Being able to gracefully merge no matter how bad of a situation the idiot in front of me leaves behind would be far more beneficial for day to day use than off the line speed.
- supermatt 6y ago

sandworm101 6y ago

>> You could limit the initial torque in software, but that’d kill the joy of the EV. All electric cars are torque-limited. They simply have to be. A static electric motor, of the type needed for higher speeds, given full voltage would not only snap bits of the drivetrain but rip apart its own mounts. So they are all limited to various degrees. The limiting factor on low-speed power for EVs isn't the motor. It's the strength of the drivetrain and ability of the battery system to provide the necessary current/voltage without cooking something.

luma 6y ago
Is this still true with the use of SynRM motors (as deployed by Tesla)?
- sandworm101 6y ago
  All electric motors boil down to magnets pulling and pushing on each other to make movement. Whether the torque protection is via software, circuitry, or mechanical wizardry doesn't really matter. They all need it somewhere to prevent static magnetic forces from pulling everything else apart.
throwaway0a5e 6y ago
>All electric cars are torque-limited. They simply have to be. A static electric motor, of the type needed for higher speeds, given full voltage would not only snap bits of the drivetrain but rip apart its own mounts. So they are all limited to various degrees. Electric motors are far, far, more forgiving to drive-train components than sporty vehicles with manuals and medium duty trucks of equivalent power levels because there is no clutch to dump. Sure it's not quite as forgiving as an automatic transmission but it's close.
- sandworm101 6y ago
  No. Electric motors are potential torque beasts. That is why they, ALL of them in cars, are mated to motor controllers. The controller may be integrated into the motor assembly so as to give the impression that the motor is tame, but the reality is that every electric motor has the potential for damaging/dangerous levels of torque. https://en.wikipedia.org/wiki/Motor_controller https://en.wikipedia.org/wiki/Motor_controller "A motor controller is a device or group of devices that can coordinate in a predetermined manner the performance of an electric motor. [...] regulating or limiting the torque, and protecting against overloads..."

Mauricebranagh 6y ago

I think top gear did this when they staged a drag race between the original Tesla and its Donor car. The amount of torque and electric vehicle can put out is huge.

baybal2 6y ago

> instant torque that an electric vehicle puts out just shreds a gearbox. On other hand, you can put way more beefier gears, as you need less of them.