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Lift-Off Oversteer strikes again

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Old 04 August 2000, 09:53 AM
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Airmiles
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Aha! Now I no longer need to be a refugee on 22b...

Well, this is a combined confession and plea for advice. Scoobynet wasn't the only thing that ceased to be last weekend, and as I counted at least 8 scoobys passing the recovery lorry (Welshpool to London), it's best to fess up.
Yep, my baby (DBM MY00 5-door)is dead - at the grand age of 6 days 19 hours 45 minutes. This is why...

I was making progress through the Welsh borders en route to Coed y Brenin, when 6 miles west of Welshpool I entered a double-right, on a constant throttle, at 60 (honest!). After the first apex, I lifted off slightly to adjust line for the second, the back stepped out, I steered into that, then it came back the other way SOO fast - effectively a "highside" for any other bikers out there. Thank god for armco. When I got out the car, the reason was obvious - the road was slick with a mixture of drizzle and tree-sap sufficient to make me slip.

What worries me is, what could/should I have done? I think I'd have made the corner happily if I had kept the power on, but what should I have done when the back did step out? Get back on the power? Gently? Hard?

The tyres were scrubbed-in at 500 miles, fairly warmed up, and I'd been driving quite comfortably on the slightly-damp surface up to that point.

Any clues? The posts on 22b all seemed to conclude that the answer was more throttle, not less.

Thanks

Old 04 August 2000, 10:47 AM
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DavidRB
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First of all, my condolences to the departed. Hope you were alright too. Also, mucho respect for admitting it in public.

Strange though it may seem, more throttle really is the answer, coupled with no opposite lock.

Lifting off tips the car forward onto the front wheels. In a 4WD vehicle, the effect is more pronounced, because engine-braking occurs on all four wheels. This gives you more grip at the front of the car.

At the point where the slide began, you probably had tyre slip at the front and the back, but the rear slide was more pronounced. Turning the front wheels left brought them "off the end" of the tyre slip-angle/grip curve and back to a point where they could grip, this was exaccerbated by lifting off which pushed weight onto the front wheels (more grip) and off the back (less grip).

The end result is entirely predictable, from a four-wheel drift, the car suddenly has grip at the front but the tyres are pointing off the road, so that's where the car goes.

A 4WD vehicle can be balanced in a slide, but only by keeping the wheels pointing straight, not by turning into the slide. In an RWD car, there is no "pull" from the front tyres, so you just point them where you are sliding and the car will go sideways. In 4WD, the fronts are pulling the car along, so steering into a skid will pull the car out of it, and it will rotate pretty damned quickly if you lift off at the same time. To overcome the pull of the fronts, they have to slide them just like the rears, so you need to give them a similar slip angle by steering straight ahead.

Now for the advice! When you get your car back, book yourself on a Wetter the Better course with Don Palmer, you can practice on the MIRA wet-handling circuit until your face hurts from grinning!

Thanks for posting this, hopefully other people can learn from it.
Old 04 August 2000, 11:17 AM
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muddy
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DavidRB,

Is there anything on the web about this "wetter the better course" at MIRA, Contact details, prices etc.
The coures sounds like it's good knowledgeable fun!!!!!
And something the normal scooby driver should be looking at doing!

Muddy.
Old 04 August 2000, 04:26 PM
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DavidRB
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Don (
Old 04 August 2000, 11:09 PM
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Richard Gledhill
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Yep, agree with the explanation above. I found this out the hard way myself at the Abingdon track day a couple of weeks ago. Coming round a fast corner at 70 or so, flat on the throttle, thought "I'm not going to make it" so I lifted off a bit to bring the nose into line - too much and so the weight shifted, the back came round a bit, touched the grass, and round I went. I should have kept hard on the throttle and fed the steering lock back off to bring the wheels back to maximum grip and let the car pull itself through the corner. You live and learn...

Thankfully I found mine out on the track - unlucky your experience was on the road

Richard
Old 05 August 2000, 09:30 PM
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Bob Rawle
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Also from experience on the track the correct thing to do is as already stated, more throttle not less, you will be amazed at how much extra turn in you get ... the "wetter the better" course is definately a must.

Glad you are ok, the car can be replaced.

Bob
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