thanks for asking
January 20th, 2006In today’s entry to GM’s FastLane Blog, Jack Keebler, GM Director of Advanced Concepts asks if GM should stick to FWD or consider RWD for their smaller performance models. He cites the success of past performance Saabs as proof that FWD can work in performance models but sagely observes many concepts are signalling a return to RWD in upcoming small car models.
Here is the response I submitted:
“There’s no question in my mind that FWD only offers one advantage to the consumer: packaging due to the transverse engine layout.
But this layout often forces the use of unequal length halfshafts and you can’t push the engine back where its favorable for weight distribution because the powertrain must be nestled between the wheels. (Interestingly the old Saabs you mention use a longitidinal layout – later transverse layouts had more turque steer and the high power caused traction issues. That aside what is good for rally conditions without electronic aids does not necessarily translate to pavement driving with stability control present counter unwanted yaw).
For small, low-powered commuter car, FWD is fine but as power and torque and engine weight increase a longitudinal layout with rear drive or at the very least all wheel drive that doesn’t wait for torque to overpower the front wheels before kicking in. Limited slip front differential as in the Cobalt SS is a step in the right direction – kudos to GM for giving enthusiasts the option.
The rear drive layout neccesitates more robust rear suspension and structure and complicates manufacture but you didn’t ask which was cheaper to build you ask which should GM build to show leadership in the industry.
Since the advent of traction and stability control I see no argument remaining against rear wheel drive except – again – space efficiency.
The dynamic prowess of the Solstice is due in large part to the RWD design and recent models that have flopped back to RWD have met with huge sucess in the market. In fact I’d venture that part of the appeal of trucks and SUVs is their rear drive bias in most conitions and the consequent lack of torque steer.