Saturday, January 21, 2006

GM Wants to Know: Rear-Wheel-Drive (With AWD, Too) or Front-Wheel-Drive for Fun Driving

Head over to GM's FastLane blog and check out Jack Keebler's post on the General's internal discussions about which is better, rear or front wheel drive. Says the GM Director - Advanced Concepts Group:

"One of the things that GM would like to better understand is the level of enthusiasm for rear-wheel drive versus front-wheel drive, particularly for young buyers of compact and sub-compact cars.
"Our belief is that front-wheel drive cars can be very rewarding to drive if properly set up. We also like the interior packaging space advantages, low mass and poor-weather traction of front-drive vehicles."

There are already 159 comments posted in response to Keebler's observations and I am sure there will be many more because this is a debate that has been going on since the earliest days of the automobile

Having raced vehicles with both powertrain configurations, I found Keebler's observation that front-wheel-drive "cars can be very rewarding to drive if properly set up" particularly interesting. Keebler is offering a very carefully worded observation that I believe also contains an unstated qualification.

The qualification is this: Front-wheel-drive vehicles can be very rewarding to drive on the street if properly set up. Put the same vehicle on a race track, however, and more often than not it's driver will see only the back bumpers of competitors with rear-wheel-drive.

Keebler is right, of course, and there are numerous extremely entertaining front-wheel-drive vehicles, not the least of which are the VW Golf R32, Acura RSX and Focus SVT. I've had loads of fun on race tracks over the years while driving such vehicles, especially the Rabbit GTI in which Scott Goodyear taught me how to threshold brake (this was before he was the famous Scott Goodyear).

But asking the front tires to brake, steer and convey power to the road is simply too much to ask. That is why understeer is such an inherent characteristic of high performance driving in a front-wheel-drive vehicle. In the matter of vehicle dynamics, you can only defy physics so far (unless your name is Colin Chapman or Aryton Senna, of course).

The rear-wheel-drive vehicle simply has higher breakaway thresholds in all three areas. That is why a rear-wheel-drive vehicle is typically more fun to drive on the race track, especially if it happens to have a V-8 or some other high-power engine, good balance front to back and responsive steering and brakes.

On the street, however, it is almost never prudent to drive at the same level of intensity as on a race track, so the vast majority of drivers rarely approach the limits of their vehicles. It is certainly possible to set up a front-wheel-drive vehicle that is quite neutral and responsive in most phases of driving.

That being the case, it would surprise me to see manufacturers moving too far away from the front-wheel-drive configuration for compact and sub-compact vehicles for precisely the reasons Keebler notes.

Packaging efficiency for occupants is simply better with the powertrain together under the hood, rather than stretching front to back of the vehicle. When space in the passenger cabin and trunk are at a premium, it makes good sense to go with front-wheel-drive.