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Discussion Starter #1
Folks, in order to fit the Leaf motor/gear reducer into my truck frame, I had to lengthen both half shafts but one was lengthened more than the other by about 200mm. Will there be an appreciable torque steer produced by doing this?
 

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It's not a big problem. Most front wheel drive vehicles have unequal length half shafts, including the Leaf that the drive unit came from.

Torque steer turns out to be about factors other than just shaft length.
  • Much of the problem is suspension reaction to drive forces - Ford found in the days of the Taurus SHO (which pushed the limit for the time of power-to-weight with FWD) that just putting in stiffer suspension bushings eliminated most of the torque steer. Ford and GM have both built sophisticated front suspensions to substitute for the usual Macpherson struts in specific FWD models with particularly high power, such as the Focus RS.
  • The problem with length could be with CV joint angles, and that's one reason that some drivetrains (including the Leaf) have a steady bearing partway along the length, so the jointed sections on similar in length on each side, even though one side has more overall length.
  • The problem with length could be with torsional stiffness (although that would cause only a brief imbalance between sides as the shafts wind up a tiny fraction of one revolution), and so longer shafts are sometimes made thicker.
AWD vehicles with traditional longitudinal engine layout put the front diff beside the engine, and have very different total shaft length (and usually even somewhat different jointed portion lengths). Even the "symmetrical" Subaru system actually has a longer shaft on one side, because the differential is offset in current and recent versions.

The Leaf uses a steady bearing on the right-side shaft, making the jointed portion shorter. The extension for the LT presumably lengthens that, so the jointed portions are now similar in length, but the right side has that extra portion from differential to steady bearing. That combination is typical for modern transverse-engine vehicles.
 

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Discussion Starter #3
Great, I won't worry about it then. Now on to battery box design. Seems the sky is the limit in designing these.
 
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