RWD vs. FWD
#1
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RWD vs. FWD
I drive both the IS250 and ES350, mostly the IS.....and I can't tell the difference between RWD and FWD, except that there is a big hump in the middle of the back passenger area of the IS, making legroom unbearable. I asked my husband to explain the difference, and his response was "in a skid, you will know" and ended the discussion before hitting for work. What is that supposed to mean? I've never been in a skid, so how would I know. Or is one better or worse during a skid? Or it has something to do with the direction you turn the wheel during a skid?
#2
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In a straight line or in normal driving, it's hard to tell the difference between the two. You'll be able to tell more of a difference if/when you start to drive the car harder and get closer to the limits of their respective handling capabilities.
In short, the weight distribution (front to rear) is the biggest difference with most RWD cars having a closer to neutral (50% front, 50% of the cars weight in the rear) whereas most FWD cars are closer to 60% front and 40% rear.
Having a neutral weight balance helps with acceleration especially in the higher hp cars because the weight balance actually moves to the rear when the car launches. It works the opposite for the FWD cars as the front end lightens at launch and you get less traction.
It's also beneficial for braking. More weight in the rear allows the car to use more of the rear brakes.
Handling also benefits from RWD. The rear tires will help more in a turn as they support more weight. Also, since the tires have a finite level of grip. Having the rears accelerating the car while the fronts do the pointing alleviates handicapping the fronts with both duties. Hope I've made sense.
FWD does have it's benefits also.
1. less drivetrain inefficiencies (puts more power to the ground unless it has so much hp that it overcomes the fronts at which point RWD would have an advantage)
2. better for slow acceleration in the snow as it has more static weight over the fronts
3. usually understeers more so it's 'safer' to the average driver in emergency situations.
In short, the weight distribution (front to rear) is the biggest difference with most RWD cars having a closer to neutral (50% front, 50% of the cars weight in the rear) whereas most FWD cars are closer to 60% front and 40% rear.
Having a neutral weight balance helps with acceleration especially in the higher hp cars because the weight balance actually moves to the rear when the car launches. It works the opposite for the FWD cars as the front end lightens at launch and you get less traction.
It's also beneficial for braking. More weight in the rear allows the car to use more of the rear brakes.
Handling also benefits from RWD. The rear tires will help more in a turn as they support more weight. Also, since the tires have a finite level of grip. Having the rears accelerating the car while the fronts do the pointing alleviates handicapping the fronts with both duties. Hope I've made sense.
FWD does have it's benefits also.
1. less drivetrain inefficiencies (puts more power to the ground unless it has so much hp that it overcomes the fronts at which point RWD would have an advantage)
2. better for slow acceleration in the snow as it has more static weight over the fronts
3. usually understeers more so it's 'safer' to the average driver in emergency situations.
Last edited by al503; 10-10-06 at 11:33 AM.
#3
a very basic answer is this...
RWD means that the engine sends all of the power to the rear wheels via the transmission. It gives great launch and is regarded as the best layout for race cars.
FWD is exactly the opposite.
The skid remark is because generally FWD is better in snow and rain because the car's engine sits above the drive wheels pushing a LOT of weight down on the wheels which helps it with traction and holding onto the pavement. Driving a RWD vehicle in the snow is not-so-fun (I live in New England) because there is much less weight in the rear of the vehicle and therefore less downforce on the drive wheels, which causes them to loose grip much easier in snow and rain.
Again, this was a very basic answer... but i hope it helps.
RWD means that the engine sends all of the power to the rear wheels via the transmission. It gives great launch and is regarded as the best layout for race cars.
FWD is exactly the opposite.
The skid remark is because generally FWD is better in snow and rain because the car's engine sits above the drive wheels pushing a LOT of weight down on the wheels which helps it with traction and holding onto the pavement. Driving a RWD vehicle in the snow is not-so-fun (I live in New England) because there is much less weight in the rear of the vehicle and therefore less downforce on the drive wheels, which causes them to loose grip much easier in snow and rain.
Again, this was a very basic answer... but i hope it helps.
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#7
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Ok....just in case I'm in a skid, which hopefully will never see in my lifetime,
what would I do any different from a RWD and FWD?
Hopefully that 'what you call again' ....o yeah VSC takes control.
what would I do any different from a RWD and FWD?
Hopefully that 'what you call again' ....o yeah VSC takes control.
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#11
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The position of the engine is much more of a factor in spinouts than which wheels are driven. That's why the old rear-engine Porsches were such a handful.
While you can certainly provoke power oversteer with the IS, given the forward weight distribution and traction control you ought to be able to stay out of trouble unless you do something really dumb.
Not so much forgiving as intuitive. If the front wheels are skidding (car is understeering), your normal reaction is to get off the gas, which shifts the weight forward, putting more on the front wheels, helping them to regain traction. If you break traction on the rear wheels (car is oversteering), getting off the gas will shift weight to the front wheels, making your situation worse. Depending on your speed (and how close you are to losing traction at the other end) you may actually have to (gently) step on the gas to shift weight to rearward to regain traction and drive out of the skid.
There is alot to be said for taking a car control course at a racing school; they'll induce skids and teach you (in a real car) how to correct them. Haven't done that myself, but I'd like to.
While you can certainly provoke power oversteer with the IS, given the forward weight distribution and traction control you ought to be able to stay out of trouble unless you do something really dumb.
FWD is the most forgiving of mistakes, much easier to control
There is alot to be said for taking a car control course at a racing school; they'll induce skids and teach you (in a real car) how to correct them. Haven't done that myself, but I'd like to.
Last edited by Bichon; 10-10-06 at 01:27 PM.
#13
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I had a 300hp Toyota Solara and now the 306hp IS350 I can tell the difference when accelerate hard. FWD feels like pulling you forward and the RWD of IS350 feels like pushing you from behind. It's a different feeling. Most cars are still FWD because that's what they, the researchers and engineers concluded the FWD is easier to control in a emergency situation. Understeer is easier to control than oversteer. RWD is more performance oriented and FWD is just...FWD. Not to be biased but most people under normal driving wont' notice any difference. Since all the Lexus cars have traction control and all the brake assisting it's hard for you to screw up, either FWD or RWD. Drive whatever you like (as long as they're Lexus!)
#14
Yes, but when you screwed up, trying to recover understeer at high speeds is nearly impossible.
But RWD on the other hand, at it's limits, and if you lose control, there is a _much_ larger chance of recovery.
But RWD on the other hand, at it's limits, and if you lose control, there is a _much_ larger chance of recovery.
#15
You may need to provide an example of what you mean by screwing up. 99.9% of the time FWD is easier for the general public to control.