• 2 Posts
  • 13 Comments
Joined 10 months ago
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Cake day: October 23rd, 2023

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  • Remember that Consumer Reports weights infotainment and electronic issues the same as engine or transmission problems.

    They literally do not do this.

    From their site:

    Engine major, engine cooling, transmission major, drive system, electric motor and EV battery problems are more likely to take a car out of service and to be more expensive to repair than the other problem areas. Consequently, we weight these areas more heavily in our calculations of model year overall reliability verdict. Problems such as broken trim and in-car electronics have a much smaller weight. Problems in any area can be an expense and a bother, though, so we report them all in the reliability history charts.





  • While software can be used to manage traction it will always be reactive in a way mechanical lockers aren’t. The reason a locker is so good for offroading is because the wheels spin at the same speeds, preventing power “leaking out of the system” via wheelslip because the grip of every other locked wheel prevents a single low-traction wheel from slipping.

    Independently powered wheels don’t have the proactive traction-management of mechanical lockers and thus are limited to reactive traction-management. That’s not to say independent motors can’t be extremely effective off-road, but mechanical-lockers will be more capable in serious offroading. The physical connection of mechanical lockers work in real-time.


  • A virtual locker doesn’t work as well as a physical locker offroad because there’s no leverage limiting wheelslip. In a mechanical locker you only get wheelspin when grip is low enough for both wheels to spin, while a virtual locker will get wheelspin when the grip of one tire is surpassed. Per-wheel motors lack this leverage too, making them not as good as a physical locker. A system with mechanical lockers on both axles with a locked center-differential does even better because you’ll only get wheelspin if all four wheels lose traction.



  • While you could have an all-wheel drive system with a transfer-case/center-differential in an EV, it would have worse performance in most scenarios coupled with much higher losses. By minimizing the amount of parts the electric motor(s) have to spin, you reduce losses and improve efficiency.

    Needing to package drive shafts throughout the length of the car eats into passenger room too, that’s why so many ICE cars have rear transmission-tunnels.

    The one scenario I can think of where a center-differential/transfer-case would fare better is with lockers in an off-road situation.