hey, so this maybe sound like a dumb question, but i was thinking about it, and could not come up with an answer
why do rwd cars seem to handle better than fwd cars??
all i know is that my 240 is more fun to drive than all the other cars i've driven
i'm **assuming** that it has something to do with the fact that the drive wheels have no weight on them, cause the engine is usually in the front
but then why do mid and rear engine cars also handle very well
someone please enlighten me!
why is rwd better??
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Q45tech
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Tires have x amount of friction, when you ask them to change directions [steer] and move the vehicle.........the friction is divided vectorially between the two requests.
Going straight it doesn't matter FWD or RWD except the end with the most weight [on tires] generally has the most traction.
When you accelerate the dynamic weight shift lifts the front and increases weight on the rear. So the rear during extreme acceleration may have more instanteous weight on the tires than the front....[more friction on rear]......[braking the opposite occurs].
On A RWD car the aft mounted transmission, drive shafft, rear differential, real rear suspension tends to balance out [spread out the weight of the vehicle.Ideally one would want 50/50 each tire having exactly the same load [static weight].......FWD tend to be 60/40 whereas RWD tend to be closer to 50/50 [54/46.....53/47].
What is really important is the Polar Moment of Inertia.......how much weight is distributed in front of/behind the supporting springs! body overhang........more than half the weight of engines sits beyond the spring.......rad, AC, bumper lights, grill
When you think of a FWD V6/V8[GM] the transmission mounted on the bisector means the FWD may have a higher Polor Moment than a heavier RWD.
On a Q 54/47 with driver aboard and fukll tank of gas means:4300x 54=2,322/2=1,161 pounds per front tire vs 989 pounds per rear tire...........172 pounds difference , but in accelerating 0.6 G if the front body rises 1.5 inches [1.5 x 146 x2=438 pounds is shifted to the rear thus the rear tires each gain 219 pounds [more or less] and the rear squats 1.8".
So the RWD car becomes shall we say perfectly balanced for acceleration.
Going straight it doesn't matter FWD or RWD except the end with the most weight [on tires] generally has the most traction.
When you accelerate the dynamic weight shift lifts the front and increases weight on the rear. So the rear during extreme acceleration may have more instanteous weight on the tires than the front....[more friction on rear]......[braking the opposite occurs].
On A RWD car the aft mounted transmission, drive shafft, rear differential, real rear suspension tends to balance out [spread out the weight of the vehicle.Ideally one would want 50/50 each tire having exactly the same load [static weight].......FWD tend to be 60/40 whereas RWD tend to be closer to 50/50 [54/46.....53/47].
What is really important is the Polar Moment of Inertia.......how much weight is distributed in front of/behind the supporting springs! body overhang........more than half the weight of engines sits beyond the spring.......rad, AC, bumper lights, grill
When you think of a FWD V6/V8[GM] the transmission mounted on the bisector means the FWD may have a higher Polor Moment than a heavier RWD.
On a Q 54/47 with driver aboard and fukll tank of gas means:4300x 54=2,322/2=1,161 pounds per front tire vs 989 pounds per rear tire...........172 pounds difference , but in accelerating 0.6 G if the front body rises 1.5 inches [1.5 x 146 x2=438 pounds is shifted to the rear thus the rear tires each gain 219 pounds [more or less] and the rear squats 1.8".
So the RWD car becomes shall we say perfectly balanced for acceleration.
q45tech, you forgot the simple fact that it is the drivetrain layout that *god* intended.
* insert your spiritual guide or creator spirit here
yashin, if you are really interested in the details of how else the drivetrain layout effects your car's characteristics, I suggest the book "race car vehicle dynamics" -by milliken & milliken
it covers everything imaginable... in sometimes nauseating detail.
In my opinion the traditional front engine, rear drive layout is only improved when the transmission is mounted in the rear...a` la 928.
too bad you had to remove the entire rear suspension and exhaust to remove the transmission.
* insert your spiritual guide or creator spirit here
yashin, if you are really interested in the details of how else the drivetrain layout effects your car's characteristics, I suggest the book "race car vehicle dynamics" -by milliken & milliken
it covers everything imaginable... in sometimes nauseating detail.
In my opinion the traditional front engine, rear drive layout is only improved when the transmission is mounted in the rear...a` la 928.
too bad you had to remove the entire rear suspension and exhaust to remove the transmission.
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Q45tech
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Just like the newer Corvette with rear mounted transmission. Where you put the 400 pound transmission counts big. Across the front whhels, behind the engine or attached to the diff.
Always lovely to imagine a long drive shaft spinning at 7,000 rpm in every gear not just once in direct [1:1 gear ratio].
Always lovely to imagine a long drive shaft spinning at 7,000 rpm in every gear not just once in direct [1:1 gear ratio].
Re: why is rwd better??
yashin wrote:i'm **assuming** that it has something to do with the fact that the drive wheels have no weight on them, cause the engine is usually in the front
but then why do mid and rear engine cars also handle very well
In a nutshell:Power oversteer is fun.Power understeer is not.
More weight on the drive wheels give you more traction, But the amount of traction increase due to download doesn't go up as fast as the amount of force required to haul heavier end of the car through the corner. You'll run out of tire on the heavier end first.
Mid/rear engine cars are manuverable, but handle "differently". Very balanced in braking - heavy understeer in acceleration. Push one past its limits and it'll snap before you know what had happened, as the heavy rear end swings around the front wheels like a pendulum.
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s13sr20chris
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Torque steer is unappealing.
Imagine yourself accelerating out of a corner. With RWD the power is applied to the rear wheels and fronts deal only with direction. With FWD, power and direction are being handled by only the front tires and as a result tire friction can be overcome more quickly. This means velocity is compromised in as much as instead of four tires handling loads only 2 are actively engaged. Poorer use of available control surfaces (tires).
Imagine yourself accelerating out of a corner. With RWD the power is applied to the rear wheels and fronts deal only with direction. With FWD, power and direction are being handled by only the front tires and as a result tire friction can be overcome more quickly. This means velocity is compromised in as much as instead of four tires handling loads only 2 are actively engaged. Poorer use of available control surfaces (tires).
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greg_atlanta
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For me it's mostly about weight balance.... RWD cars ride nicer because the front and rear shocks/springs can be calibrated to be similar since both are supporting the same amount of weight. On a FWD car the front springs have to be a lot stiffer to support the extra weight. FWD cars also nosedive when braking hard.
If you ever hit an ice patch, a RWD car will spin on an axis. A FWD car will sling itself into a ditch.
If you ever hit an ice patch, a RWD car will spin on an axis. A FWD car will sling itself into a ditch.
Quote »If you ever hit an ice patch, a RWD car will spin on an axis. A FWD car will sling itself into a ditch.[/quote]
You're not kidding. In snow, ice, and any slippery conditiong give me a RWD car with good tires over any FWD car any day. With RWD, you can lose traction in the rear and maintain total control of the car. While it might be harder to break the drive wheels loose in a FWD car, once you do you're just along for the ride. IN slippery conditions a RWD car is so much more predictable. When I hit this snow or ice I know exactly what this car is going to do and how to correct it. With FWD it's like a toss of the dice, who knows what it's going to do.
You're not kidding. In snow, ice, and any slippery conditiong give me a RWD car with good tires over any FWD car any day. With RWD, you can lose traction in the rear and maintain total control of the car. While it might be harder to break the drive wheels loose in a FWD car, once you do you're just along for the ride. IN slippery conditions a RWD car is so much more predictable. When I hit this snow or ice I know exactly what this car is going to do and how to correct it. With FWD it's like a toss of the dice, who knows what it's going to do.
my driving instructor was telling me about his old camaro or whatever he had when he was young, ported/blueprinted/etc engine and all, and they would all hook up the pumps from the windshied fluid sprayers into the wheel wells and put bleach in the resevoirs, when they wanted to do a smokey *** burnout, he just hit the button and went at it..
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psychic_mechanic
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Q45tech wrote:Just like the newer Corvette with rear mounted transmission. Where you put the 400 pound transmission counts big. Across the front whhels, behind the engine or attached to the diff.
Always lovely to imagine a long drive shaft spinning at 7,000 rpm in every gear not just once in direct [1:1 gear ratio].
Porsche used this in their 924/944/928 cars for years. I don't know why it took so long to catch on to "mainstream" cars like the Corvette. You end up with such a nicely balanced car.
I like the fact that MORE companies are offering RWD vehicles over the next couple years as opppsed to less. Life is good....
my theories are as follows
FWD = "point and go" car, user friendly, and when NOT pushed to the limit, reacts like a trained monkey. Braking in turns, hell braking during turns in large snow banks, and you still have control.
less noise ( in older cars anyway) cuz you dont have that driveshaft undertneath
more room!, once again due to lack of a driveshaft
RWD = better perfromance when pushed to the LIMIT, like someone said oversteer is better than understeer, ( no slip is better but oversteer is easier to control), takes more skill to drive AT THE LIMIT.
however at the hands ofa newbie, under wet/snowy conditions may be less reialable ( like massive braking during turns)
FWD was built for the masses, RWD was built for the few.
FWD = "point and go" car, user friendly, and when NOT pushed to the limit, reacts like a trained monkey. Braking in turns, hell braking during turns in large snow banks, and you still have control.
less noise ( in older cars anyway) cuz you dont have that driveshaft undertneath
more room!, once again due to lack of a driveshaft
RWD = better perfromance when pushed to the LIMIT, like someone said oversteer is better than understeer, ( no slip is better but oversteer is easier to control), takes more skill to drive AT THE LIMIT.
however at the hands ofa newbie, under wet/snowy conditions may be less reialable ( like massive braking during turns)
FWD was built for the masses, RWD was built for the few.
bdawg46 wrote:Is it just me, or does that just sound really good??
okay listen how many people actualy drove cars back in the day, and how many of them drove well, not to mention the fact that alot of them were slow as hell so it would not matter if you were 4wd rwd or fwd the chances of a person losing grip due to "aggressive driving" was a rarity
A person buys a performance car, they want to buy a car with power. You put 200 plus hp on a front drive car and the torque steer is unbearable. My friend has a 03 Acura TL, when you give it too much gas on a turn, those front tires bounce all over the place. I keep reading reviews for the new TL in the car magazines and all they keep on saying is that it would be a perfect car if it was RWD. FWD is ok if you want to drive a Civic that's only 130hp, but a TL that’s 270hp, that's way too much power for the front tires. Hopefully Honda/Acura gets there act together and stop using that tired Accord platform for all their cars and develop a RWD platform for the TL & RL. Maybe then they can compete with the Germans.
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Q45tech
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Re: (CrazyS14240)
FWD has 1.5-3% lower friction losses........on an equal basis < 1.0 mpg but that was important on Cadillac/GM where every 0.1 mpg mattered when you are rounding UP and paying a gas guzzler tax in increments.
Front wheel drive is over $1,300 less expensive to manufactuer [rear suspension, stand alone diff, driveshaft].
Front wheel drive is over $1,300 less expensive to manufactuer [rear suspension, stand alone diff, driveshaft].
Re: why is rwd better?? (yashin)
All replys are good - heres my 2 cents:
RWD give a near 50/50 weight ratio front/rear becuase of the driveshaft which gives excellent handling around corners and fast turns.
I noticed that the suspension and brakes also tend to last much longer on RWD.
All the technical stuff aside - Its just hella of lot better than FWD on the fun factor.
RWD give a near 50/50 weight ratio front/rear becuase of the driveshaft which gives excellent handling around corners and fast turns.
I noticed that the suspension and brakes also tend to last much longer on RWD.
All the technical stuff aside - Its just hella of lot better than FWD on the fun factor.
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AmoebAssassin
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In a racing situation, RWD will increase time between pit stops as well. A FWD card will place all three critical forces (accelleration, braking, cornering) on the front tires and considerably less load on the rear tires. This causes the fronts to heat up and subsequently wear much faster than the rear tires. Not only does the pinning of all three critical loads on one set of tires decrease the life of the tires significantly, but as the front set of tires wears, your coefficient of static friction in the front drops, meaning your FWD car will take longer to accellerate, brake, and will be less eager to rotate in turns as the race goes on.
An RWD car, on the other hand, assigns the front tires with cornering and braking while the rear tires deal with accellerating the car. This more even distributed load results in more even and therefore longer wear on the tires, meaning you stay out of the pits longer. Also, as your tires die, an RWD car will understeer in a normal turn due to the loss of static friction in the tires responsible for turning; however, a RWD car with worn tires can still be made to oversteer using the throttle to break the back loose. Thus, you can last longer between tire changes and still maintain a safer and more controlled/intuitive driving experience with worn tires.
An RWD car, on the other hand, assigns the front tires with cornering and braking while the rear tires deal with accellerating the car. This more even distributed load results in more even and therefore longer wear on the tires, meaning you stay out of the pits longer. Also, as your tires die, an RWD car will understeer in a normal turn due to the loss of static friction in the tires responsible for turning; however, a RWD car with worn tires can still be made to oversteer using the throttle to break the back loose. Thus, you can last longer between tire changes and still maintain a safer and more controlled/intuitive driving experience with worn tires.