So with FWD you would want to brake while turning in order to get the
car to rotate. By applying the brakes while turning, you're using the
momentum of the car to induce a bit of oversteer as you enter the turn.
That would require braking a bit later than you would for RWD. If that's
what you mean, then I finally understand what "trail braking" is.
My experience with power oversteer in RWD is slightly different from
what you describe. With the RWD cars I've driven, I find that I can feel
power oversteer before the rear tires start really spinning. That is, as
I apply the throttle though a turn, I can feel the power oversteer
helping to rotate the car, before the car actually slides or spins. The
hard part is controlling it -- that is, riding the razor's edge between
just enough power oversteer to help rotation, without letting it turn
into a power slide.
> -----Original Message-----
> From: John J. Stimson-III [mailto:john@harlie.idsfa.net]
> Sent: Wednesday, April 03, 2002 11:29
> To: Michael R. Clements
> Cc: 'james creasy'; 'Autocross'
> Subject: Re: FWD vs. RWD -- differences?
>
>
> On Wed, Apr 03, 2002 at 11:00:24AM -0800, Michael R. Clements wrote:
> > Yes it is desirable to stay within the traction limits. But you can
> > start to get oversteer or understeer as you approach the limits,
> > before you start sliding all over the place.
>
> Rear wheel drive cars tend to understeer under power just
> like you'd expect from a front wheel drive car, up to the
> point where the rear wheels break loose. But if you break
> traction due to too much power, you've exceeded the limits
> and are going to be slower than if you had kept the tires
> slipping but not spinning. I think that's what James means.
>
> FWD will give a little more understeer under power and
> wheelspin will come more easily due to weight transfer. The
> limits of handling will be slightly different but the general
> behavior is similar. Also, FWD vehicles tend to be more
> nose-heavy than RWD or mid-engined vehicles.
>
> I would think that in a FWD car you would want to trail-brake
> more to rotate the car early in the turn, and make the apex
> as late as possible so you can be going straight and on the
> gas as early as possible.
>
> A RWD car will give itself more traction to the rear wheels
> under power, allowing that power to be applied while still
> turning and not overwhelm the rear tires. So they should
> have a more neutral apex given the same corner, and should be
> able to handle long constant radius turns better.
>
> John "physics theorist and hack driver" Stimson
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