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I don’t know about towing “the entire island of Fiji”, but the torque figure for that semi is insane. The average semi has 1000lb-ft, mining trucks have 10k. A

I don’t know about towing “the entire island of Fiji”, but the torque figure for that semi is insane. The average semi has 1000lb-ft, mining trucks have 10k. And that’s their peak. The XOS semi has 35k (!)

benglish11 4y ago
Yeah diesel electric trains are also in that 35k lb-ft range. Torque is a huge advantage electric motors have over ICE which makes them great in these types of applications.
- sandworm101 4y ago
  At those numbers the limitation is not the engine tech but the strength of the drivetrain. Most any electric motor can snap an axle if not regulated properly. Most of the largest mining trucks are already electric drive, have been for many years, with an IC generator powering an electric motor. That is easier at scale than building a massive transmission.
lostlogin 4y ago
Something will surely give. At what point is wheel spinning or turning the hubs inside the tyres likely? I know nothing about trucks.
SigmundA 4y ago
Seems misleading since they are quoting wheel torque which is after gearing. A semi with 1850 ft lbs engine torque with a 13:1 first gear and 3:1 drive axle will put 72150 ft lbs to the wheel. Nobody quotes wheel torque because you can get any wheel torque you want through gearing.
- billfruit 4y ago
  Do electric drive trains have gearing? Can't the applied torque be regulated electrically?
  - SigmundA 4y ago
    Yes there is usually a single speed gear case with gear reduction to increase wheel torque. Sometimes you will see multi-speed transmission on EV's but it is not as necessary since electric motors put out maximum torque at 0 rpm and spin up to 20,000 rpm. The Tesla semi for instance has 4 model 3 motors putting out 307 ft lbs each with a single speed gearbox of 23:1 on the front drive and 15:1 on the rear drive allowing a kind of electronically controlled two speed system. So the front drive can put down 307 * 2 * 23 = 14122 ft lbs while the rear can put down 307 * 2 * 15 = 9210 ft lbs for a total of 23332 at the wheels. The main point to remember is torque can be increased by gearing while power cannot, and measuring torque at the wheels seems impressive but doesn't tell you much, you can get a lawnmower engine to put huge torque numbers at the wheels with the right gearing and most EV have gear reduction except maybe hub motors even then they might use planetary reduction.
_fat_santa 4y ago
That's because they are measuring Torque at the hubs which gives these insane numbers. If you "convert" the torque, it's much more realistic.
- deleted 4y ago
  [deleted]

benglish11 4y ago

Yeah diesel electric trains are also in that 35k lb-ft range. Torque is a huge advantage electric motors have over ICE which makes them great in these types of applications.

sandworm101 4y ago
At those numbers the limitation is not the engine tech but the strength of the drivetrain. Most any electric motor can snap an axle if not regulated properly. Most of the largest mining trucks are already electric drive, have been for many years, with an IC generator powering an electric motor. That is easier at scale than building a massive transmission.

lostlogin 4y ago

Something will surely give. At what point is wheel spinning or turning the hubs inside the tyres likely? I know nothing about trucks.

SigmundA 4y ago

Seems misleading since they are quoting wheel torque which is after gearing. A semi with 1850 ft lbs engine torque with a 13:1 first gear and 3:1 drive axle will put 72150 ft lbs to the wheel. Nobody quotes wheel torque because you can get any wheel torque you want through gearing.

billfruit 4y ago
Do electric drive trains have gearing? Can't the applied torque be regulated electrically?
- SigmundA 4y ago
  Yes there is usually a single speed gear case with gear reduction to increase wheel torque. Sometimes you will see multi-speed transmission on EV's but it is not as necessary since electric motors put out maximum torque at 0 rpm and spin up to 20,000 rpm. The Tesla semi for instance has 4 model 3 motors putting out 307 ft lbs each with a single speed gearbox of 23:1 on the front drive and 15:1 on the rear drive allowing a kind of electronically controlled two speed system. So the front drive can put down 307 * 2 * 23 = 14122 ft lbs while the rear can put down 307 * 2 * 15 = 9210 ft lbs for a total of 23332 at the wheels. The main point to remember is torque can be increased by gearing while power cannot, and measuring torque at the wheels seems impressive but doesn't tell you much, you can get a lawnmower engine to put huge torque numbers at the wheels with the right gearing and most EV have gear reduction except maybe hub motors even then they might use planetary reduction.

_fat_santa 4y ago

That's because they are measuring Torque at the hubs which gives these insane numbers. If you "convert" the torque, it's much more realistic.

deleted 4y ago
[deleted]