I purchased a 2004 Nissan Altima with front-wheel drive last winter. At one point, my right front tire was stuck on ice but my left front tire was on dry asphalt. I tried to get off the ice, but the right tire (the one on ice) kept spinning, while the left tire, on dry pavement, did nothing. I was under the impression that if one tire slipped, the traction would be switched to the non-slipping tire (left). When I called the dealer, he stated that the car is manufactured so that the right tire gets the power, and that next time I should consider parking so that my left tire is on ice and the right tire is on dry asphalt. I asked him if he was serious, and he said yes. What is the real story about front-wheel-drive cars - specifically, the 2004 Nissan Altima - with regard to which wheel gets the power on ice?
Wow, you guys are a wellspring of misinformation!
All cars have something called a differential. The differential is a magical box of gears (sorry, that's the best I can do without using diagrams and my hands) that send power to the wheels while - at at the same time - allowing the left and right wheels to turn at different speeds.
Why is that necessary? Because when you're going straight, your left and right wheels rotate at the same speed, and all is right with the world. But when you turn left or right, the inside wheel has to turn slower because it's traveling a shorter distance than the outside wheel travels (draw a picture of where a car's wheels go when it turns, and you'll see that the outside arc is longer than the inside arc). If the inside wheel couldn't turn slower, you'd drag it along the pavement. Not a good way to turn.
The only downside of the differential is that because of the way it works, there are two properties that are always true. One is that the combined speed of the two wheels always stays the same. So the outside wheel speeds up by the exact amount that the inside wheel slows down.
And, more importantly for your purposes, the differential always sends the exact same amount of torque (twisting power) to both wheels.
Why is that a problem? Well, if one wheel is on ice and it requires practically zero torque to make it spin (which is what happens on ice), then the other wheel - the one on dry pavement - also gets zero torque. So the wheel on ice spins freely, and the car doesn't move.
That's been addressed over the years in some cars with a technology called "limited slip differential," which detects when one wheel is slipping and sends torque to the other wheel. But that wasn't available on your car.
These days, most cars have computer-controlled dynamic stability control, traction control and ABS brakes, which address the same problem.
But to answer your question, under normal circumstances, both wheels get power in your 2004 Altima - as they do in pretty much every car. And whoever answered the phone at your dealership had his head up his differential.
About two years ago, I was restoring a '65 Corvette coupe. One day, my neighbor and his son, about 4 years old, stopped in the garage to say hello and have a look. His son pointed at the engine, which was sitting on the garage floor, and said, "That goes there" - pointing to the front of the car. Pretty smart young man. I was impressed. As they were leaving, the father said, "Thank you for preserving our automotive heritage." That kind of took me by surprise. Most of my time in the garage is spent muttering disparaging remarks about GM engineers - the car was designed like pure crap. So here's my question: In restoring classic cars, am I actually pursuing a noble cause, or just goofing off in the garage? Thanks.
You're goofing off in the garage.
Actually, goofing off and acting nobly are not mutually exclusive. I happen to think tinkering is noble. We're a throw-away society now: Something breaks, we toss it, pile it up in a landfill and buy another one that was made in China.
So when you take the time to tinker, to figure out how things work, to repair, restore and renew ... I think you are doing something worthwhile, regardless of what you're tinkering with.
You're wasting-not and wanting-not. You're keeping stuff out of landfills. You're conserving resources by not buying more new stuff. You're finding value in things already made.
And you're staying out of your wife's hair and out of the barrooms all afternoon. That's definitely noble.
But more importantly, you're continuing a great human tradition of working with your hands and solving problems.
That little neighbor kid may wander back into your garage in a few years and take an interest in what you're doing. He may ask if he can help, and then borrow some of your tools and learn to tinker himself. Seriously, you may end up inspiring him to pursue an interest in fixing things. Or a career in engineering, or inventing.
Then when the North Koreans hack our electrical grid and put us back in the Stone Age, maybe you two will save us - by setting fire to that '65 Corvette and keeping us warm.
So keep up the noble work. And enjoy goofing off, too.
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