How many drive wheels?

[JJR512]

A co-worker told me earlier today that some front-wheel-drive cars only have one drive wheel. In other words, he was telling me that only one of the front wheels is connected to the transmission and engine.

I was like...

I have never, ever heard of such a thing and it goes against all I know about automotive drive systems. I believe that if only one wheel was being driven, the car would go to one side...for example, if the left wheel was the one drive wheel, then when you go forward, the car would pull to the right.

This comment from my co-worker came after we went to go pick up another co-worker who was stuck at home because her car was stuck on ice. Specifically, her right front tire was on ice, and her front left tire was on pavement. She said that when she stepped on the gas, the right wheel (on ice) spun, while the left wheel (on pavement) stayed still. How she knew that, I'm not quite sure (perhaps she was mistaken). Then my co-worker proceeded to explain that she probably has one of those FWD cars that only has one drive wheel. That's when I got all...

Can someone (someone who knows for an absolute fact, unquestionably, undoubtedly) please tell me if I'm right or my co-worker was right?

 

[paul_valaru]

A co-worker told me earlier today that some front-wheel-drive cars only have one drive wheel. In other words, he was telling me that only one of the front wheels is connected to the transmission and engine.

I was like...

I have never, ever heard of such a thing and it goes against all I know about automotive drive systems. I believe that if only one wheel was being driven, the car would go to one side...for example, if the left wheel was the one drive wheel, then when you go forward, the car would pull to the right.

This comment from my co-worker came after we went to go pick up another co-worker who was stuck at home because her car was stuck on ice. Specifically, her right front tire was on ice, and her front left tire was on pavement. She said that when she stepped on the gas, the right wheel (on ice) spun, while the left wheel (on pavement) stayed still. How she knew that, I'm not quite sure (perhaps she was mistaken). Then my co-worker proceeded to explain that she probably has one of those FWD cars that only has one drive wheel. That's when I got all...

Can someone (someone who knows for an absolute fact, unquestionably, undoubtedly) please tell me if I'm right or my co-worker was right?

both are drive wheels, but only one wheel at a time.

it alternates.

 

[paul_valaru]

EDIT

both are drive wheels, but there is a differnetial, which is why sometimes only one will spin when it is slippery out. Of course it is path of least resistance, so the one on ice will spin, unless you have traction control

...

look up differentials

 

[JJR512]

both are drive wheels, but there is a differnetial, which is why sometimes only one will spin when it is slippery out. Of course it is path of least resistance, so the one on ice will spin, unless you have traction control

...

look up differentials

This is what I thought was true. I knew about differentials, and I tried to explain that's why one wheel can turn faster than the other, because you need that to happen in turns. But my co-worker just turned up the radio. So I guess he showed me.

 

[Altron]

Because the drive wheels need to spin at different speeds when cornering (if you're turning right, the left wheel has to travel further than the right wheel), they have a gearbox that allows them to rotate at different speeds. However, in most cars, with an 'open differential', one wheel can be stopped while the other spins. Since they can rotate independently, and since the one wheel was just sliding, and the other had traction on the pavement, all of the power went to the wheel with the least resistance, making the icy one spin while the one on pavement stayed still.

However, some cars have special differentials that don't allow all the power to be sent to one wheel, called LSD (limited slip differential) or positraction. Some offroad vehicles have locking differentials. A car with the differentials locked cannot turn easily (because to turn, one of the wheels needs to skid) , but it's usable if you're stuck in the mud.

Most cars tend to have open diffs. A lot of sports cars have LSDs because it gives you better traction.

 

[A.B.Normal]

My 4x4 has LSD (trac-loc)

 

[Gato_Solo]

My Audi has AWD...

 

[JJR512]

...A car with the differentials locked cannot turn easily (because to turn, one of the wheels needs to skid) , but it's usable if you're stuck in the mud.

I've experienced this myself. Not the mud, but what it's like to turn when the diff is locked. Only the diff wasn't locked deliberately. It was an ambulance I was driving (on a Ford E-450 chassis). I started noticing that on some sharper turns, I could hear and feel some tire scrubbing from the rear. It had also been making a horrible whining noise...well, it had been doing that for a while; it's not uncommon in ambulances, because the rear ends wear pretty quick. We all know what that sound means. But that day, it was a lot worse, a lot more harsh than it had been. I figured that the diff wasn't long for this world. I put it in for service and was told that the diff was very low on oil, that it was in fact leaking. It was replaced after that.

 

[chcr]

A co-worker told me earlier today that some front-wheel-drive cars only have one drive wheel. In other words, he was telling me that only one of the front wheels is connected to the transmission and engine.

I was like...

I have never, ever heard of such a thing and it goes against all I know about automotive drive systems. I believe that if only one wheel was being driven, the car would go to one side...for example, if the left wheel was the one drive wheel, then when you go forward, the car would pull to the right.

This comment from my co-worker came after we went to go pick up another co-worker who was stuck at home because her car was stuck on ice. Specifically, her right front tire was on ice, and her front left tire was on pavement. She said that when she stepped on the gas, the right wheel (on ice) spun, while the left wheel (on pavement) stayed still. How she knew that, I'm not quite sure (perhaps she was mistaken). Then my co-worker proceeded to explain that she probably has one of those FWD cars that only has one drive wheel. That's when I got all...

Can someone (someone who knows for an absolute fact, unquestionably, undoubtedly) please tell me if I'm right or my co-worker was right?

Paul has given you the straight poop. Ask your co-worker this: If the car only has one drive wheel, why does it have two drive axles?

 

[JJR512]

I'm sure that in his world, since it has only one drive wheel, it also has only one drive axle.

(Maybe I should bet him a thousand dollars that if we looked under the hood of this woman's Toyota Corolla, which was the car that was stuck on the ice, we would find two drive axles!)

 

[SouthernN'Proud]

I'd bet you couldn't see the axles from opening the hood m'self...

 

[JJR512]

Well I guess I'd lose a thousand dollars...Thanks for the heads-up!

I guess we want to look up from below?

 

[Professur]

JJR, your friend needs to watch less TV and read a book. He's heard someone talk about how a differential works and didn't understand half of it. Ignore him like the idiot he is. Tell him I said so.