FWD vs RWD for snow and ice

[MetroMPG]

Originally Posted by Isaac Zachary

Thinking that if you lose control in a RWD you'll crash backwards isn't realistic.

My super-scientific, not-at-all anecdotal analysis from watching far too many hours of winter dash cam videos agrees.

You need a LOT of unobstructed room for a vehicle to rotate 180 degrees after the driver loses control in slippery conditions; the crashes always seem to happen somewhere in the sideways portion of the skid. (That's for typical cars. MR2, 911, Beetle, etc. excepted.)

Originally Posted by cRiPpLe_rOoStEr

I never drove on snow, and most of my driving had been with FWD econoboxes.

Loose gravel is comparable to some snow conditions. Except gravel is MUCH noisier!

(Driving in snow can be a very peaceful experience - almost no tire noise, depending on the type & depth of snow. It must be an almost magical experience in an EV with no drivetrain noise.)

[Isaac Zachary]

Originally Posted by JSH

Packaging / manufacturing cost.

It is much easier to package a liquid-cooled engine and transaxle in the front of the car. You put the radiator up front and coolant lines are short. Same with the hoses between the engine and heater core. Throttle cables are easy to route. Shifter linkages are shorter and less complicated.

As a manufacturer I can also make a sedan, coupe, wagon, and hatchback variation and not have to touch the front half of the car.

Then there is luggage / cargo room. With a rear engine car you basically just have the frunk. With a front engine car it is easy to fold down the rear seat to double the cargo room.

Does this mean that economy EV's Will continue to be Front Wheel Drive since you'd need longer cooling hoses or will it not matter as much since the cooling hoses will probably be much smaller? I guess we'll find out.

[JSH]

Originally Posted by Isaac Zachary

Does this mean that economy EV's Will continue to be Front Wheel Drive since you'd need longer cooling hoses or will it not matter as much since the cooling hoses will probably be much smaller? I guess we'll find out.

So far vehicles build on dedicated EV platforms have been mostly switching to RWD standard with AWD as an option. Tesla, VW, and Hyundai / Kia have RWD as standard. We will likely see the same thing when Toyota shows us their first e-TNGA vehicle later this week.

Motor cooling tends to be integrated with the battery which is centered under the car so FWD or RWD doesn't matter as much

There are no mechanical throttles or shifters so that doesn't matter.

[Isaac Zachary]

Originally Posted by JSH

So far vehicles build on dedicated EV platforms have been mostly switching to RWD standard with AWD as an option. Tesla, VW, and Hyundai / Kia have RWD as standard. We will likely see the same thing when Toyota shows us their first e-TNGA vehicle later this week.

Motor cooling tends to be integrated with the battery which is centered under the car so FWD or RWD doesn't matter as much

There are no mechanical throttles or shifters so that doesn't matter.

Most modern cars don't have mechanical throttles either.

I read VW is going to get rid of FWD for good too.

So RWD and FWD have different advantages and disadvantages when on the move. I can't say one is better than the other in those regards and is more a personal preference than a this is better than that. Front bias and rear bias both feel different. Having the rear end swing out, even just a litte, is something you either love or you hate. (Ask my wife). Having the front just keep going straight is something you either prefer or you don't in comparison to the alternative.

But where FWD really shines is when you're stuck in deep snow or mud. RWD only gives you two options; FWD gives you six. I think car manufacturers know this and are eager to sell AWD vehicles to those of us who have become accustom to that feature of FWD cars.

Reading the GT2 manual:

"...There are some handling advantages for the FF (front engine/front-wheel drive) design. Because the weight of the engine and transmission is over the driven axle, traction in wet or slippery conditions can be very good. At steady speeds or under a low rate of acceleration in poor conditions, a front-wheel drive car can outperform a rear-wheel drive car. Front-wheel drive cars have a long history of success in rallying because of their abilities in poor conditions. Forward weight distribution also contributes to stability...

"...The MR (mid-engine/rear-wheel drive) design can also decrease the frontal area of a two-seat sports car, and allow other aerodynamic advantages. But perhaps the most imortant advantage of the design for a high-performance vehicle is that it concentrates the vehicle's mass near its center of gravity. This decreases its inertial resistance to quick changes of direction, increasing maneuverability. Because of this maneuverability, a mid-engine car can be set up to make full use of its tires and corner faster by having a small amount of oversteer designed in. That can make it very nervous and tricky to drive at the limit. It takes skill and fast reactions to be able to drive such a car well, but a skilled driver can take full advantage of a mid-engine car's cornering abilities..."

[freebeard]

I went looking for proof that the New Beetle concept was supposed to be rear-engined, unsuccessfully; but I did find this: www.greencarreports.com/...vw-bus-hybrid-that-never-was-the-microbus-prototype-of-1977





An ottomotor/electromotor, or mid/rear hybrid?

[Isaac Zachary]

Originally Posted by freebeard

I went looking for proof that the New Beetle concept was supposed to be rear-engined, unsuccessfully; but I did find this: www.greencarreports.com/...vw-bus-hybrid-that-never-was-the-microbus-prototype-of-1977





An ottomotor/electromotor, or mid/rear hybrid?

Cool! I actually had a similar idea when I had the Super Beetle and thought I could do anything.

[JSH]

Originally Posted by Isaac Zachary

Cool! I actually had a similar idea when I had the Super Beetle and thought I could do anything.

I've thought of using the transfer case from an AWD Astro van to make a hybrid. Mechanically it would be pretty simple. The controls are what scares me!

[cRiPpLe_rOoStEr]

Originally Posted by Piotrsko

The VW bug was still a viable car in Mexico until recently, and CR can probably verify the recent manufacture in South America.

I remember when the Beetle was phased out in Mexico in 2003. When it comes to Brazilian production, it was shutdown in '86, but resumed from late-'93 to mid-'96 with the so-called Itamar series (as in '93 Brazilian then-president Itamar Franco personally inquired Volkswagen about the possibility of resuming the production). Even though the Beetle as is doesn't comply neither to current safety and emission standards or to most of the newer preferences in the new car market, I'm sure some modern equivalent to the Beetle retaining a few traditional features such as rear-engine and rear-wheel drive while including comfort enhancements such as air conditioning and power steering would be quite successful. Brazil is still pretty much an agrarian country, so when it comes to off-road ability it's a desirable feature which is not the same with the mainstream front-wheel drive econoboxes and sometimes a 4WD becomes out of budget.

On a sidenote, keeping the engine and other components more concentrated at the rear end wouldn't be out of question, even if it resorted to a water-cooled engine like it's quite common to see in adaptations.

[Isaac Zachary]

Originally Posted by JSH

I've thought of using the transfer case from an AWD Astro van to make a hybrid. Mechanically it would be pretty simple. The controls are what scares me!

I'd be interested in how that would work. The Astro's "AWD" transfer case is basically the same clutch operated transfer case that the Chevy/GM trucks use only without low range and manual 4x4 mode. It's just "stuck" in auto mode.

When I had my 2001 Chevy Astro I dreamed of installing an S-10's or Sierra's transfer case and hooking up the controls so it could work as a fully controllable low range 4x4 transfer case. Seems like this has been done quite a few times in the Astro/Safari community.

[cRiPpLe_rOoStEr]

Makes me wonder to which extent a traditional 4WD truck would behave in the snow with the high-range 4WD engaged according to the load as the weight bias would be shifting.

Originally Posted by Isaac Zachary

I'd be interested in how that would work.

I'd take with a grain of salt the viability of repurposing a transfer case into some sort of power-split device.

clutch operated transfer case

I'd rather not rely on a clutch-operated transfer case. Viscous coupling is more reliable.