I know it's been mentioned, but it's really a simple concept. Regardless if the car is front or rear or all-wheel drive, high performance tires don't do well in snow and ice. Try a Porsche Carrera 4 with Pirelli P-Zeros in snow, and see how far you go.
And the M+S tires ("mud and snow") are pretty good. I've had a set of Z-rated Yokohamas that I've had up to 160 mph, and driven in the snow with no problems.
People actually do do that for fun, believe it or not! I think there is a term for driving a FWD backwards to get some wild tail out action (in a secluded parking lot, for example), but it escapes me at the moment.
It will rarely be 50/50 in any sort of dynamic situation. There's only 2 times when it will be 50/50- when it's standing still and when in a turn while you have happened upon juuuust the right amount of acceleration. The latter situation doesn't necessarily coincide with the fastest, hardest turn, either.
It will rarely be 50/50 in any sort of dynamic situation.
Don't intend to be an ass, but since the metric is done when the car is standing still, what you said doesn't really mean anything, does it?
When the car is moving, things are still going to be shaky in the rear if 70 percent of the weight is in the front. Likewise, in a porsche you're still going to understeer. Mid engine cars exist because of weight balance issue. weight balance does matter.
...and that's precisely why that metric has less meaning than most make it out to be- it's done as a static test because it's easy to measure. However, that means very little when the car is actually moving through different acceleration vectors (where the effective weight balance can sweep through an entire range of numbers). The tires will generate grip according to the dynamic weight distribution. They don't care what the balance is when the car is static. That's just an easy number to put in a magazine or product lit. At the very most it can suggest the potential for good handling traits, but that's about it.
As for mid-engine cars, you will find that many of them are actually more similar to FWD cars (wrt to imbalance), except it is somewhat near 40% to the front and 60% to the rear. Weight distribution is a secondary issue here, as the real benefit is extracted from the location of the polar moment of inertia being near the rear wheels such that the front wheels can steer around them with the least effort (henceforth enhanced steering capability and responsiveness). An added benefit is that the majority weight of the car is over the drive wheels, so this contributes to the tires getting a good bite upon launch.
OK Chief. We'll get you an Rx-7 (a 3rd gen. . . the one that is wicked fast) and you'll be singing a different tune. edit: It's very hard to control, even in first gear.
Shawn: pretend your civic was rear wheel drive and had twice as wide tires and more than twice the power.
...and that's precisely why that metric has less meaning than most make it out to be- it's done as a static test because it's easy to measure. However, that means very little when the car is actually moving through different acceleration vectors (where the effective weight balance can sweep through an entire range of numbers). The tires will generate grip according to the dynamic weight distribution. They don't care what the balance is when the car is static. That's just an easy number to put in a magazine or product lit. At the very most it can suggest the potential for good handling traits, but that's about it.
As for mid-engine cars, you will find that many of them are actually more similar to FWD cars (wrt to imbalance), except it is somewhat near 40% to the front and 60% to the rear. Weight distribution is a secondary issue here, as the real benefit is extracted from the location of the polar moment of inertia being near the rear wheels such that the front wheels can steer around them with the least effort (henceforth enhanced steering capability and responsiveness).
The steering argument was interesting info about MR cars. So far I've thought FF cars only have worse steering because they have to use the same wheels to steer and accelerate, but if you're correct, then there is also the reason that the steering wheels have more weight on them. Can you elaborate a bit on this subject?
I thought some 50/50 cars like the RX are thought to have excellent steering. How much better can it get? Does this matter for anyone that is not a F1 driver?
AFAIK, the point of all this to have predictable and smooth weight shift between maximum accel / maximum braking / maximum steering. I've understood that the best way to achieve this is to have the driver sit on top of the center of mass in the car, so that the driver feels rotational and acceleration forces that are exactly similar to the whole car's. Am I wrong in this? Don't MR drivers sit noticeably in front of the center of mass?
The steering argument was interesting info about MR cars. So far I've thought FF cars only have worse steering because they have to use the same wheels to steer and accelerate, but if you're correct, then there is also the reason that the steering wheels have more weight on them.
Yes, in part, the front tires on a FWD have a lot of work to do, hence are not the greatest steerers under various situations. Outside of a track racing situation, you can avoid the bulk of this problem by simply following an edict to not stab the throttle while cornering and not attempt to start a turn while under heavy throttle. They can have a bit of overlap in moderation, but keep the extremes as separate events for the best results. The problem arises when people attempt to drive a FWD car like they would a RWD car, and then complain that the experience was not to their liking. As with cars of any configuration, you always play to that car's strengths to get the best performance.
The side perk is that the center of mass being mostly to the front in a FWD car, allows for easy, consistent, and stable tail-out action (should the suspension be set up to encourage it). There is very little weight back there to "get out of control", so a bit of play back there can be useful and "friendly".
The issue of lots of weight over the front drive wheels manifests itself predominantly as a setup that is more resistant to weight transfer issues wrt putting power to the ground in a stable manner.
The bottomline is that if you have a non 50/50 weight distribution then that sets up the situation where one end of the car will spin about the other end more easily than vice versa. Depending on which end the drive wheels are, that could radically change the stability of the car with that weight distribution. Since turning the car is essentially spinning one end about the other in a gentle manner, this could either play to the car's nature or work against. Similarly, inducing some tail-out or countersteer behavior may either play to or against a car's nature.
Quote:
I thought some 50/50 cars like the RX are thought to have excellent steering. How much better can it get? Does this matter for anyone that is not a F1 driver?
Overall, it's a relatively light car altogether and low to the ground as a result of its smallish stature, so it gains a lot of its handling prowess just from that. Since it is 50/50, one could argue that it is easier to throw more weight to the front or back depending on how you pitch the car in a manuever to increase traction on that end of the car where it would be most beneficial. The one time 50/50 helps directly is if you are in a perfect coast (no loss or gain in velocity) through a hard turn (but who drives their RWD car only like that?).
Quote:
AFAIK, the point of all this to have predictable and smooth weight shift between maximum accel / maximum braking / maximum steering. I've understood that the best way to achieve this is to have the driver sit on top of the center of mass in the car, so that the driver feels rotational and acceleration forces that are exactly similar to the whole car's. Am I wrong in this?
Possibly it could help, but my guess is that the driver will more likely adjust to the car to get the necessary feedback sooner or later. It could be a disconcerting experience if one shifts to different cars of different natures, though. This is not to say that one way is necessarily better than the other, however.
Quote:
Don't MR drivers sit noticeably in front of the center of mass?
Generally so, I would imagine. It really depends on the specific MR car.
Just get used to it and get an idea of how far you slide when you try to decelerate. I am used to driving a Ford Explorer which grips really well with just the standard tires. I really only use the 4WD when you need to pull out or up somewhere that is snowy so you can actually do it, our driveway is pretty steep.
As for when I drive our car, well it slides everywhere haha but you can control it.
Normally I don't drive much slower if at all when it's snowy out, just stay in the tracks in front of you and start slowing down long before you plan on stopping.
I love driving in the snow and man does that video look like fun. I'm not sure I'd ever feel completely safe driving a car over top of ice like that though!
Comments
I know it's been mentioned, but it's really a simple concept. Regardless if the car is front or rear or all-wheel drive, high performance tires don't do well in snow and ice. Try a Porsche Carrera 4 with Pirelli P-Zeros in snow, and see how far you go.
And the M+S tires ("mud and snow") are pretty good. I've had a set of Z-rated Yokohamas that I've had up to 160 mph, and driven in the snow with no problems.
Many people seem to regard Hakkapeliittas as the best.
Originally posted by GardenOfEarthlyDelights
Maybe he can drive it backwards.
People actually do do that for fun, believe it or not!
Originally posted by GardenOfEarthlyDelights
Maybe he can drive it backwards.
Obviously a joke here, but the 7 has perfect 50/50 balance. That's why the handling in dry conditions is so predictable.
By the way, loved that video of driving on ice.
Originally posted by Randycat99
It will rarely be 50/50 in any sort of dynamic situation.
Don't intend to be an ass, but since the metric is done when the car is standing still, what you said doesn't really mean anything, does it?
When the car is moving, things are still going to be shaky in the rear if 70 percent of the weight is in the front. Likewise, in a porsche you're still going to understeer. Mid engine cars exist because of weight balance issue. weight balance does matter.
As for mid-engine cars, you will find that many of them are actually more similar to FWD cars (wrt to imbalance), except it is somewhat near 40% to the front and 60% to the rear. Weight distribution is a secondary issue here, as the real benefit is extracted from the location of the polar moment of inertia being near the rear wheels such that the front wheels can steer around them with the least effort (henceforth enhanced steering capability and responsiveness). An added benefit is that the majority weight of the car is over the drive wheels, so this contributes to the tires getting a good bite upon launch.
Originally posted by Splinemodel
OK Chief. We'll get you an Rx-7 (a 3rd gen. . . the one that is wicked fast) and you'll be singing a different tune. edit: It's very hard to control, even in first gear.
Shawn: pretend your civic was rear wheel drive and had twice as wide tires and more than twice the power.
No one made you drive more than 5 mph.
Cheers
Scott
Originally posted by Randycat99
...and that's precisely why that metric has less meaning than most make it out to be- it's done as a static test because it's easy to measure. However, that means very little when the car is actually moving through different acceleration vectors (where the effective weight balance can sweep through an entire range of numbers). The tires will generate grip according to the dynamic weight distribution. They don't care what the balance is when the car is static. That's just an easy number to put in a magazine or product lit. At the very most it can suggest the potential for good handling traits, but that's about it.
As for mid-engine cars, you will find that many of them are actually more similar to FWD cars (wrt to imbalance), except it is somewhat near 40% to the front and 60% to the rear. Weight distribution is a secondary issue here, as the real benefit is extracted from the location of the polar moment of inertia being near the rear wheels such that the front wheels can steer around them with the least effort (henceforth enhanced steering capability and responsiveness).
The steering argument was interesting info about MR cars. So far I've thought FF cars only have worse steering because they have to use the same wheels to steer and accelerate, but if you're correct, then there is also the reason that the steering wheels have more weight on them. Can you elaborate a bit on this subject?
I thought some 50/50 cars like the RX are thought to have excellent steering. How much better can it get? Does this matter for anyone that is not a F1 driver?
AFAIK, the point of all this to have predictable and smooth weight shift between maximum accel / maximum braking / maximum steering. I've understood that the best way to achieve this is to have the driver sit on top of the center of mass in the car, so that the driver feels rotational and acceleration forces that are exactly similar to the whole car's. Am I wrong in this? Don't MR drivers sit noticeably in front of the center of mass?
Originally posted by Gon
The steering argument was interesting info about MR cars. So far I've thought FF cars only have worse steering because they have to use the same wheels to steer and accelerate, but if you're correct, then there is also the reason that the steering wheels have more weight on them.
Yes, in part, the front tires on a FWD have a lot of work to do, hence are not the greatest steerers under various situations. Outside of a track racing situation, you can avoid the bulk of this problem by simply following an edict to not stab the throttle while cornering and not attempt to start a turn while under heavy throttle. They can have a bit of overlap in moderation, but keep the extremes as separate events for the best results. The problem arises when people attempt to drive a FWD car like they would a RWD car, and then complain that the experience was not to their liking. As with cars of any configuration, you always play to that car's strengths to get the best performance.
The side perk is that the center of mass being mostly to the front in a FWD car, allows for easy, consistent, and stable tail-out action (should the suspension be set up to encourage it). There is very little weight back there to "get out of control", so a bit of play back there can be useful and "friendly".
The issue of lots of weight over the front drive wheels manifests itself predominantly as a setup that is more resistant to weight transfer issues wrt putting power to the ground in a stable manner.
The bottomline is that if you have a non 50/50 weight distribution then that sets up the situation where one end of the car will spin about the other end more easily than vice versa. Depending on which end the drive wheels are, that could radically change the stability of the car with that weight distribution. Since turning the car is essentially spinning one end about the other in a gentle manner, this could either play to the car's nature or work against. Similarly, inducing some tail-out or countersteer behavior may either play to or against a car's nature.
Quote:
I thought some 50/50 cars like the RX are thought to have excellent steering. How much better can it get? Does this matter for anyone that is not a F1 driver?
Overall, it's a relatively light car altogether and low to the ground as a result of its smallish stature, so it gains a lot of its handling prowess just from that. Since it is 50/50, one could argue that it is easier to throw more weight to the front or back depending on how you pitch the car in a manuever to increase traction on that end of the car where it would be most beneficial. The one time 50/50 helps directly is if you are in a perfect coast (no loss or gain in velocity) through a hard turn (but who drives their RWD car only like that?).
Quote:
AFAIK, the point of all this to have predictable and smooth weight shift between maximum accel / maximum braking / maximum steering. I've understood that the best way to achieve this is to have the driver sit on top of the center of mass in the car, so that the driver feels rotational and acceleration forces that are exactly similar to the whole car's. Am I wrong in this?
Possibly it could help, but my guess is that the driver will more likely adjust to the car to get the necessary feedback sooner or later. It could be a disconcerting experience if one shifts to different cars of different natures, though. This is not to say that one way is necessarily better than the other, however.
Quote:
Don't MR drivers sit noticeably in front of the center of mass?
Generally so, I would imagine.
As for when I drive our car, well it slides everywhere haha but you can control it.
Normally I don't drive much slower if at all when it's snowy out, just stay in the tracks in front of you and start slowing down long before you plan on stopping.
I love driving in the snow and man does that video look like fun. I'm not sure I'd ever feel completely safe driving a car over top of ice like that though!