Torque Steer

Agreed, but they can at least have some control over where they will crash! I would rather the rear hangs out a bit than run wide and die! What about unexpected slippery conditions like fish slime or spilled fuel on the roads? It CAN happen to anyone.

The average driver wouldn't.

Alternatively, hamfisted application of the throttle could send the car spinning into opposing traffic.

You shouldn't be driving that close to the limits on a public road.

No it wouldnt. Only if you cant drive.

No but people do, including me. The point is that a slippery bit of road can be unexpected. You may have thought the road looked fine. As a motorcyclist you must have come across diesel spills and the like. Looks JUST like a damp parch of road under the trees. You can never know.

Which is the whole point of where this thread is going. It's safer to put unskilled drivers (ie. a large proportion of the driving population) in a FWD car, given that understeer only needs you to lift off the throttle to bring it back in line.

Right...... so, we should all be driving RWD cars because there's idiots out there who believe that exceeding the limits of their car control is a good thing to do on public roads?

FWIW, in the case of a diesel spill and RWD, you'd actually end up spinning off the road with even less predictability than if you're driving something FWD.

Yet on a roundabout in a FWD if you lift off, you can end up spinning the car.

Who said it was a good thing. But it happens to thousands of people every day. They are called accidents.

You may, I know I wouldnt. And I prefer the options that rear drive gives me. I can decide where to crash for myself. I chhoose something soft and cheap rather than the front of an oncoming truck.

Mostly they just slow down and understeer less. Unless its dry and you are going at really high speed and purposly unbalancing the car by using its own sudden turn in (yaw) moment of inertia to try and get oversteer and then back off. Even then its almost impossible to spin a fwd because all they want to do is go straight on regardless of what you attempt. You have to go really mad to spin one and swap ends! Thats the problem they WANT to understeer any time you acc or dec. Because unlike the rear wheel that are doing nothing but lateral forces the fronts have to both acc or decc the car due to the engine. This leaves less tyre grip for the lateral cornering forces. So you get understeer in any condition apart from dipped clutch or where the engine rate of deceleration mathces the cars natural dec. In other words only when there is no energy going into or coming from the front wheels can they allow all their grip for cornering.

Spin 360 in a Pug.

!ding!

Correct.

Perhaps manufacturers would sell more RWDs if airbags were placed in the back?

It's been very difficult to do more than a 180 in the front wheel drive cars, because I guess of weight distribution.

360s are tricky, 45 degrees and even 90, with a bundle of opposite lock and tyre smoke is quite possible, and catchable..... apparantly.

It has nothing to do with weight distribution. Grip is more or less doubled as weight doubles. A zero wheeled drive car would have no tendency to either understeer or oversteer, on any corner or if thrown down the road sideways by a giant! However... As soon as you connect a gearbox / drive shafts etc to a pair of wheels then that pair cannot rotate as freely. Even WITHOUT an engine in the car. The difference means that the road has to drive the transmission/diff etc. So now this pair of wheels cannot ever give as much drip in the lateral (sideways) direction as before. Some was used up already. So whichever axle this is cannot generate as much cornering force. FWD - Understeer. RWD = Oversteer. The more engine braking or engine power applied the worse this becomes.

FWD is worse though because the weight transfer under acceleration out of a roundabout say takes Weight off the front tyres, while asking them to turn the same mass of car laterally the same amount (same sideways g force) AND it expects the tyre to give extyra traction to accelerate the speed!

Under the same sitiation a rear drive car adds weight to the rear, when asking for more grip through the same weight transfer. This adds grip at the time its needed rather than reduces it, Its still possible but now you have to try harder to spin the wheel/step sideways. Its a far more efficient setup. Thats why the BMW cars in circuit racing have to carry a huge extra weight to give the others a chance.

I think you need to experience more front wheel drive machines then. Some scrub off speed and lose the understeer, some continue understeering, some have a nasty habit of suddenly snapping the rear out of line whereas some possess a feel where by the right (or wrong) steering input will have the back swinging out a little bit.

Of course, lift off oversteer is a FWD at its most unpredictable so these sorts of activities are best reserved for track days, airfield days* or somewhere else rather than an ordinary road.

*and only when they let you, heh.

Nope, it doesn't have to happen at high speed and in the dry. It'll happen at low speed, or in the wet, depending very much on the machine and driver input. There's a similar delicate throttle balancing act with a FWD too just as with a RWD, the skills required are indeed similar in some respects.

If you enter a corner too fast you get understeer no matter what end of the car is driven. What happens next depends on the driver just as much, if not more so, than the car. If you don't give the car any power, there's a chance the back end will slide out, again regardless of what end is driven. Physics dictate it. Give it some juice and almost front wheel drive machines will understeer towards the kerb. Some rear wheel drive machines will also understeer because the rear wheels, not skidding, have much better grip than the front wheels. Others will start to oversteer. The modern trend to use wide wheels, wide tyres often results in a snappier handling characteristic with little transition from skid to no-skid; if the front wheels suddenly find dig, well that's one reason why all BMWs have stability control systems - there's much less warning.

On even a relatively low powered rear wheel drive BMW you don't have to be all that brutal with the accelerator in the above circumstances for the warning light to flicker at you. Most stability control systems seem to convert oversteer into understeer anyway...

That's partially correct. It is hard to spin a front wheel drive machine in a 180, almost impossible to go further. At least starting off in a forward direction. But they don't default to understeer all of the time. As I'm about to alluded to, you need more experience of different FWDs before making that assumption.

Wrong. Some front wheel machines are set up to feel like a curious hybrid between FWD and RWD. You should try a few Alfa Romeos and some of the sporty 80s style Peugeots.

The rear wheels are not doing nothing, though.

It's just acceleration but I know what you mean.

Yes, but one must also keep squirting power into the front wheels to overcome friction otherwise you have that acceleration to deal with; that's how some FWDs understeer off the power and on the power.

Lowered Cinqs do that, too. I can confirm they are very recoverable from that kind of angle :-)

I can't remember ever spinning a front drive car without help from the handbrake.

*ding*

You have to try *very* hard to do it. Even at the height of my hooliganism I couldn't get the Cinq to spin, and that was a real handful. The 33 came close on a couple of occasions, but never really got close to swapping ends.

My favourite trick always used to be getting the spacewagon or the zafira sideways - scared the pants off other road users, and passengers in row 3...

*snort* Spacewagon

Bwahahahaha.

Nah, a few tweaks here and there, you're done.

Raising the rear tyre pressures helped. And when encountering the roundabout or corner, turn in on the power, lift off, apply some power, gentle left foot brake, then nail it... swings right round... at least on some machines.

The 33 is set up like a hybrid FWD / RWD, isn't it? I didn't push the 1.5 I tried especially hard. Pushed it for the grin not for the terror. :)