I haven't seen this discussed yet in several of the treads musing about the Semi design.
In KMan's video of the Semi drivetrain components I note that the axles have differing gear reduction ratios. The fore axle is 23:1 reduction, and the aft axle is 15:1.
I assume this is done to optimize the power delivery and efficiency through the RPM range the motors are capable of, seeing as there's isn't a multi-gear transmission.
This would seem similar to the dual-motor Model S, which has a ~9.73:1 rear reduction ratio (at least for the "large drive units), and a slightly "taller" gearing for the front motor (~9.34:1). This allows the car to cruise primarily with the front motor operating at a lower RPM range closer to it's efficiency sweet spot.
With the semi having a ~53% difference between the axles, I assume that's for the low-end torque it takes to get 80K lbs moving, and the system will be biased toward the taller geared axle at highway speeds.
Any other thoughts or implications about this design?
In KMan's video of the Semi drivetrain components I note that the axles have differing gear reduction ratios. The fore axle is 23:1 reduction, and the aft axle is 15:1.
I assume this is done to optimize the power delivery and efficiency through the RPM range the motors are capable of, seeing as there's isn't a multi-gear transmission.
This would seem similar to the dual-motor Model S, which has a ~9.73:1 rear reduction ratio (at least for the "large drive units), and a slightly "taller" gearing for the front motor (~9.34:1). This allows the car to cruise primarily with the front motor operating at a lower RPM range closer to it's efficiency sweet spot.
With the semi having a ~53% difference between the axles, I assume that's for the low-end torque it takes to get 80K lbs moving, and the system will be biased toward the taller geared axle at highway speeds.
Any other thoughts or implications about this design?