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Front wheel drive is the norm for small cars because it is cheaper and more space efficient. Furthermore, the problems with front wheel drive a proportional to

by hristov 11y ago

Front wheel drive is the norm for small cars because it is cheaper and more space efficient. Furthermore, the problems with front wheel drive a proportional to the ammount of torque the car produces. A lot of small economy cars are designed not to be very powerful, so front wheel drive is not much of a problem. But small cars that are designed to be performance cars from the beginning tend to be real wheel drive cars. See for example, the mazda miata, the toyota mr-2, the prosche cayman/boxter, the alfa romea 4c, etc. If you look carefully at powerful small cars, you will notice that the ones designed from the ground up to be performance cars tend to be real wheel drive, the ones that are designed merely as an upgrade of a less powerful economy car are often front wheel drive. The cost efficiency and space benefits of front wheel drive are mostly related to the particularities of internal combustion engines. For an electric, these are not that much of an issue. And the steering problems of powerful front wheel drive cars are very real.

tadfisher 11y ago
Torque-steer is a packaging problem; the difference in half-shaft lengths between the left and right hubs in most transaxle setups causes an uneven application of torque. If manufacturers choose to employ them, there are solutions to the problem: - Many AWD vehicles, and many 2WD Audi and VW cars, use a traditional longitudinal setup with equal-length shafts driven from a transaxle mounted in the rear of the engine. - Power-assisted steering can be employed to counteract torque-steer by receiving the current torque application as input. Like you said, an electric vehicle has neither of these problems, because they do not have to package a transaxle to one side of an ICE-driven crankshaft. There is no reason to believe that the Bolt exhibits torque-steer, and nothing in the article corroborates this suspicion. The other benefit of FWD vehicles is that understeer is much, much easier to recover from than oversteer. RWD vehicles tend to snap-oversteer the other direction when the untrained driver lifts off the accelerator too quickly; a common occurrence in YouTube videos of Mustang and Corvette conventions. Understeer can easily be recovered from by lifting off the accelerator in the same way, putting more weight on the front wheels and increasing available traction.
- hristov 11y ago
  It is not only a packaging problem, there is a fundamental physics problem that cannot be avoided. When power is produced by the front wheels they create a force between them and the ground. This is the force that causes the car to accelerate forward. But this force also puts pressure on the stickiness on the forward wheels and makes them want to slide. If you apply a lot of torque you start getting microslides, or momentary losses of traction which reduce the front wheels ability to steer the car and cause torque steer and understeer. A lot of the problems of oversteer you see in youtube videos and the like are really just very extreme cases. I doubt the Bolt, even with its electric motor, will have as much torque as a the souped up mustangs and corvettes that you usually see at those conventions. In general, for the same amount of torque, oversteer is much better than understeer, because it does not cause nearly as much loss of steering (and the little loss it causes usually goes in the right direction, i.e., helping you turn). Oversteer is the result of the rear wheels sliding, and the rear wheels are not as crucial for steering as the front wheels. Thus microslides in the rear wheels will not cause such a loss of steering authority. I remember i test drove a 200 hp front wheel drive audi, and it had noticeable understeer and torque steer problems. Then i test drove a 300 hp rear wheel drive infiniti, and it had no oversteer problems even though it had much more horsepower and torque. Of course you can always cause dangerous situations with oversteer, but you need much more power and torque to do it.
  - tadfisher 11y ago
    What you are saying, in simpler terms, is that the traction circle in FWD vehicles is limited by the fact that the same contact patch must handle both acceleration and steering. And that's true. This makes FWD setups prone to understeer. Everything you describe services this truth. What's not true is that torque-steer is caused by lots of torque overcoming available traction. The same torque is applied to both wheels in the absence of unequal-length half-shafts. You might induce understeer with the application of torque, but it will not induce a force which changes the steering angle moreso than the same understeer situation would induce on a RWD vehicle, and that's a function of the suspension setup, and mostly dependent on caster angle. Thus I submit that torque-steer is not an inherent flaw of FWD design, but of the most common packaging design in ICE vehicles. It's easy to conflate the two.

by hristov 11y ago

tadfisher 11y ago

Torque-steer is a packaging problem; the difference in half-shaft lengths between the left and right hubs in most transaxle setups causes an uneven application of torque. If manufacturers choose to employ them, there are solutions to the problem: - Many AWD vehicles, and many 2WD Audi and VW cars, use a traditional longitudinal setup with equal-length shafts driven from a transaxle mounted in the rear of the engine. - Power-assisted steering can be employed to counteract torque-steer by receiving the current torque application as input. Like you said, an electric vehicle has neither of these problems, because they do not have to package a transaxle to one side of an ICE-driven crankshaft. There is no reason to believe that the Bolt exhibits torque-steer, and nothing in the article corroborates this suspicion. The other benefit of FWD vehicles is that understeer is much, much easier to recover from than oversteer. RWD vehicles tend to snap-oversteer the other direction when the untrained driver lifts off the accelerator too quickly; a common occurrence in YouTube videos of Mustang and Corvette conventions. Understeer can easily be recovered from by lifting off the accelerator in the same way, putting more weight on the front wheels and increasing available traction.

hristov 11y ago
It is not only a packaging problem, there is a fundamental physics problem that cannot be avoided. When power is produced by the front wheels they create a force between them and the ground. This is the force that causes the car to accelerate forward. But this force also puts pressure on the stickiness on the forward wheels and makes them want to slide. If you apply a lot of torque you start getting microslides, or momentary losses of traction which reduce the front wheels ability to steer the car and cause torque steer and understeer. A lot of the problems of oversteer you see in youtube videos and the like are really just very extreme cases. I doubt the Bolt, even with its electric motor, will have as much torque as a the souped up mustangs and corvettes that you usually see at those conventions. In general, for the same amount of torque, oversteer is much better than understeer, because it does not cause nearly as much loss of steering (and the little loss it causes usually goes in the right direction, i.e., helping you turn). Oversteer is the result of the rear wheels sliding, and the rear wheels are not as crucial for steering as the front wheels. Thus microslides in the rear wheels will not cause such a loss of steering authority. I remember i test drove a 200 hp front wheel drive audi, and it had noticeable understeer and torque steer problems. Then i test drove a 300 hp rear wheel drive infiniti, and it had no oversteer problems even though it had much more horsepower and torque. Of course you can always cause dangerous situations with oversteer, but you need much more power and torque to do it.
- tadfisher 11y ago
  What you are saying, in simpler terms, is that the traction circle in FWD vehicles is limited by the fact that the same contact patch must handle both acceleration and steering. And that's true. This makes FWD setups prone to understeer. Everything you describe services this truth. What's not true is that torque-steer is caused by lots of torque overcoming available traction. The same torque is applied to both wheels in the absence of unequal-length half-shafts. You might induce understeer with the application of torque, but it will not induce a force which changes the steering angle moreso than the same understeer situation would induce on a RWD vehicle, and that's a function of the suspension setup, and mostly dependent on caster angle. Thus I submit that torque-steer is not an inherent flaw of FWD design, but of the most common packaging design in ICE vehicles. It's easy to conflate the two.