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View Full Version : AWD vs FWD vs RWD


swchang
12-08-2003, 01:21 AM
I don't mean for this to turn into another debate about AWD vs RWD, as I've been reading many of the threads and have seen that many have passionate arguments for one or the other (e.g. rumatt, jaisonline, Firefly...). What I would like to ask is where does FWD fit into this? Is there a point to FWD anymore? It seems that RWD is for a fun driving experience in dry weather and RWD with snows is mostly adequate for the wintry weather in many parts of the country. AWD is supposed to be better in wetter conditions and for climbing hills and not getting stuck in snow. Is FWD with snows generally better than RWD with snows? Is it good for anything, or is it a technology that will eventually fall by the wayside, like 8-tracks and 5.25" computer disks?

Also, my other question is about snow tires. Narrow vs. wide: any trade-offs in snow/icy conditions? Narrow is supposed to be better in driving through the snow, because you don't "hydroplane" as much, but is wide better for stopping on ice because of the greater surface area? Or are you just screwed once you've hit ice, wide tires or not?

HW
12-08-2003, 02:47 AM
I don't mean for this to turn into another debate about AWD vs RWD, as I've been reading many of the threads and have seen that many have passionate arguments for one or the other (e.g. rumatt, jaisonline, Firefly...). What I would like to ask is where does FWD fit into this? Is there a point to FWD anymore? It seems that RWD is for a fun driving experience in dry weather and RWD with snows is mostly adequate for the wintry weather in many parts of the country. AWD is supposed to be better in wetter conditions and for climbing hills and not getting stuck in snow. Is FWD with snows generally better than RWD with snows? Is it good for anything, or is it a technology that will eventually fall by the wayside, like 8-tracks and 5.25" computer disks?

Also, my other question is about snow tires. Narrow vs. wide: any trade-offs in snow/icy conditions? Narrow is supposed to be better in driving through the snow, because you don't "hydroplane" as much, but is wide better for stopping on ice because of the greater surface area? Or are you just screwed once you've hit ice, wide tires or not?

snows: i've always heard that narrow is better cuz it puts more weight on a small tire patch so it digs in better.

fwd: cheaper to manufacture. absence of centre channel for drive shaft means more room for passengers ex. new civic. more understeer is more safer for most people. does not require lots of stability electronics to keep people from hurting themselves. problem claimed by many enthusiasts is torquesteer and most trackers and street racers like a bit of oversteer for the fun and speed at turns.

awd: nice to have in many ways. more expensive, heavier car, higher fuel consumption.

rwd: more expensive. heavier than fwd, less than awd. more electronics needed to keep regular drivers from hurting themselves from oversteer. more sought after by car enthusiasts. not everyone is a car enthusiast. said to be better in the snow because the car weight is front biased on the drive wheel. can handle higher horsepowered engines. again an enthusiast issue.

KP
12-08-2003, 04:00 AM
if you have Kazaa, BBC did a short review on this where they tested a fwd/awd/rwd (Alfa 156GTA/Audi A43.0/BMW 328i). Nice video and they give you some beginner's advice on their take as well. If I had a website I'd upload it.

ObD
12-08-2003, 11:13 AM
Most cars used to be RWD, now most are FWD. Shared manufacturing costs among like components and cabin layout considerations is the rationalization. Each has it's advantages and disadvantages. I'd rather have RWD but for some people FWD is adequate.

Chris90
12-08-2003, 12:45 PM
I think the weight balance and tuning is as big a factor as the front/rear drive wheels. Drive an Acura Type R - it's an amazing drive despite front drive - it's one of my favorite cars to drive (based on a couple brief but wild stints behind the wheel). Most stock new BMWs these days drive like front drivers with heavy understeer!

Another note - drove a WRX in the snow this morning - and with its stock all seasons, it's really no better than my 325i w/ snows - kind of dissappointing - but it's great fun - 4 wheel drifts at 5 mph, on demand!

FireFly
12-08-2003, 01:25 PM
Seeing that you mentioned my name in the thread I ought to respond.

I believed that AWD was the only way to go if you lived in an area where it snows. But BMW has a very sophisticated DSC system so having a RWD with snows should be enough to get most through the winter. I agree with the previous post that AWD with AS tires will not help you as much as some may think.

RWD with AS tires is asking for trouble in the snow.

If you live in an area where you absolutely need AWD then you should probably get snow tires as well. That would be the best set up if you really need it.

But if you live in the city and get a lot of snow, get snow tires and throw a set of chains in the trunk so that if it gets so nasty that you snows can't help you, at least you will not be stranded.

I'll be looking to get snows for my AWD and I'll also throw chains in my trunk for that once in 10 year snow/ice emergency I may encounter.

Jspeed
12-08-2003, 02:15 PM
With equal tires, FWD does have a little advantage over RWD during initial acceleration.

While the car is stationary or travelling at a constant velocity, a typical FWD would have 60-65% of the vehicle weight over the drive wheels, while the same figure for a RWD is only 45-50%. How long before the RWD catches up to the FWD in term of drive wheel traction depends on how much rearward weight transfer you're able to induce.

swchang
12-09-2003, 12:50 AM
Hmm, interesting. I had no idea FWD was very popular in the US. Most of the cars I've had are RWD, although I guess they've mostly been German ones...

Anyway, what people are saying is interesting, but I'm more curious as to what the advantages of FWD are. If RWD is for the "driving experience" on dry roads and AWD is for additional stability in snow (and rain?), then FWD is for...? Is it in between AWD and RWD for driving experience and stability? :dunno:

Jever
12-09-2003, 01:44 AM
Hmm, interesting. I had no idea FWD was very popular in the US. Most of the cars I've had are RWD, although I guess they've mostly been German ones...

Anyway, what people are saying is interesting, but I'm more curious as to what the advantages of FWD are. If RWD is for the "driving experience" on dry roads and AWD is for additional stability in snow (and rain?), then FWD is for...? Is it in between AWD and RWD for driving experience and stability? :dunno:
I'm not totally sure what sense this makes but a mechanic uncle of mine (did some indy stuff for some top drivers) told me it was kind of like this: FWD>RWD in bad weather b/c the weight is over the driving tires. Kind of like why you stick sand bags in the back of a pick up truck. In snow, it can help b/c you have more weight on the pulling wheels instead of having to pack all your fat friends in the back to get up a hill.

Granted, if things are horrible, one either shouldn't be on the road or should be in a tracked vehicle.

AWD is great b/c you have (usually) equal pulling and pushing power from all 4 corners so if you lose traction on one side you have 3 more helping instead of 1 wheel. YOu don't go faster and you use more gas, but how many jeeps do you see that go "mudding" w/ 2wh drive? :)

RWD gives you a lot more control (sometimes) like "drifting" or something if you blow a corner. I've driven FWD and RWD in winter and there are plusses and minus, but at least you can get on the gas and get the rear pointed in the direction you want to go w/ a RWD where as a FWD you basically have to just accept the line you have and wait for the curb to come and brake your axle. But on the down side, on regular roads and or conditions, you might be able to hold a corner better w/ FWD w/out throwing the ass-end out for no reason and meeting Mr.Telephone pole.

Tire pressure: If it's icy out, throw on chains or ice skates as it really doesn't matter if you are overspeed. Ice isn't anyone's friend and once you hit it too fast, sit back and enjoy the ride. Snow,mud and sand, the lower the pressure the better your traction is. You want low pressure so you have more rubber on the road surface, that equals greater traction (under proper speeds of course.) Perfectly dry roads run at higher pressure and you get better gas milegae as you have a smaller contact point, but can lose some controlability.

swchang
12-09-2003, 01:56 AM
I'm not totally sure what sense this makes but a mechanic uncle of mine (did some indy stuff for some top drivers) told me it was kind of like this: FWD>RWD in bad weather b/c the weight is over the driving tires. Kind of like why you stick sand bags in the back of a pick up truck. In snow, it can help b/c you have more weight on the pulling wheels instead of having to pack all your fat friends in the back to get up a hill.

Ah... So does that mean if you have extra weight in your trunk in a RWD, you should be better off because there's more weight over the "pulling wheels"?

I read in a different thread that someone put sand bags in his trunk to help him get up hills better in his RWD w/ snows. Then someone said the manual says not to do that. :dunno:

Jever
12-09-2003, 02:40 AM
[QUOTE=swchang]Ah... So does that mean if you have extra weight in your trunk in a RWD, you should be better off because there's more weight over the "pulling wheels"?

that's exactly what I'm saying. Now it may make a difference in the car and how you drive it or are used to driving, but some more weight over the driving wheels w/ a good tire pressure and you are golden. Up until a point, then you are just going overboard. Like stick a few hundred lbs of sand in the back and it helps...and if you get truly stuck you can use those bags of sand to dig your way out too. But yes, higher weight over the back wheels, lower pressure and you have a harder time of getting stuck...unless youa re just totally snowed in.

Chris90
12-09-2003, 06:42 AM
My brother drove M1A1s in the snow at Armor School, and said they slide around like crazy, and won't stop - in fact the tanks are difficult in the snow, and tend to slide down slopes and flip over. Just thought I'd mention that.


Granted, if things are horrible, one either shouldn't be on the road or should be in a tracked vehicle.

Spiderm0n
12-09-2003, 08:46 AM
My brother drove M1A1s in the snow at Armor School, and said they slide around like crazy, and won't stop - in fact the tanks are difficult in the snow, and tend to slide down slopes and flip over. Just thought I'd mention that.


yea, its quite a sight! I saw them slide down hills in Germany. They are a huge freaking sled!

Jever
12-09-2003, 08:01 PM
yea, its quite a sight! I saw them slide down hills in Germany. They are a huge freaking sled!
I forgot about that, but I was thinking more like the Snow Cats at ski resorts and in antarctica rather than 50ton tanks w/ rubber pads on the tracks. Then again, most anything is screwed if you are on ice...except for a Zamboni!

bluer1
12-09-2003, 08:33 PM
Also, my other question is about snow tires. Narrow vs. wide: any trade-offs in snow/icy conditions? Narrow is supposed to be better in driving through the snow, because you don't "hydroplane" as much, but is wide better for stopping on ice because of the greater surface area? Or are you just screwed once you've hit ice, wide tires or not?

Just watch a WRC event (or even SCCA Pro Rally) and you'll see a lot of narrow tires with deep tread blocks.

Dunno about the FWD thing as I've never owned one - switched from Volvo to BMW when Volvo quit making RWD cars.
:thumbup:

swchang
12-09-2003, 08:42 PM
Just watch a WRC event (or even SCCA Pro Rally) and you'll see a lot of narrow tires with deep tread blocks.

Dunno about the FWD thing as I've never owned one - switched from Volvo to BMW when Volvo quit making RWD cars.
:thumbup:

Hmm, but don't the narrow tires usually have studs? :dunno:

bluer1
12-09-2003, 08:46 PM
Hmm, but don't the narrow tires usually have studs? :dunno:

Ice/snow do, gravel tires do not.

http://www.wrc.com/en_GB/Features/Content/2003_R_I_TarmacTyreTalk.htm

http://www.wrc.com/en_GB/Features/Content/feature002.htm

It's also a myth that wider tires provide more traction on pavement - they don't, they simply allow the tire to work more efficiently.