Semi gear reduction ratios

[Artful Dodger]

The two climb motors have a significantly higher gear ratio, close to double the cruising motor, there is a whole another stage to them.

I think you've misinterpreted some specs for Tesla Semi. The "acceleration" axle has two motors, while the "cruise" axle has a single motor. The gear ratios for each respectively are 23:1 and 15:1 (see post #1 above in this thread).

Cheers!

 

[GhostSkater]

I think you've misinterpreted some specs for Tesla Semi. The "acceleration" axle has two motors, while the "cruise" axle has a single motor. The gear ratios for each respectively are 23:1 and 15:1 (see post #1 above in this thread).

Cheers!

Nice find

But keep in mind that is 5 years old

I tried measuring the gears diameter from the launch video and got this

Acceleration drive units: ~18:1

Highway drive unit: ~12.5:1

For a 105 cm diameter Semi tire and with the motor at 20k rpm the acceleration drive units would do 136 mph, and the highway drive unit 197 mph, I was a bit under for the acceleration ones, and crazy low ratio for the highway one, this likely mean that the motor is the most efficient at 80 to 125 kW, which are the power needed to maintain speed on a flat road at 55 and 70 mph respectively, at 5500 to 7000 rpm

Also, if we take a Model 3 motor efficiency map, that slots right at the peak efficiency region

 

[Artful Dodger]

Acceleration drive units: ~18:1

Highway drive unit: ~12.5:1

Gear ratios check out:

• 18/12.5 = 1.44
• 23/15 = 1.53

My point is that it's not twice; that was the possible mistranslation from "dual motor" axle.

Cheers!