[QUOTE]Originally posted by Lawdog
[B]It was about 40 degrees outside, the car had been sitting for about 2 hrs and we had gone about three blocks.

 

[QUOTE]Originally posted by Tanqueray
[B]

So you did the curve at 40mph with warm tires with the 300 SDL, as opposed to ice cold tires with the S2000?
Like most cars, the 300 SDL is dialed to understeer...did you notice understeer?
Did you throttle lift in mid-curve with the 300 SDL?
And finally, what class of tires are on the Benz?

 

I think we should try and very carefully dissect this accident. Why? This is one of the few instances where the rears weren't the stock S-02s. There is a great deal for us to potentially learn here about the impact of the tires vs. other factors and the impact of the driver vs. car factors.

This one is a true opportunity. Let's learn from it rather than devolve into the typical drivel!

Here's the proper starting point (rather than carperfect vs. cardangerous.)
originally posted by Lawdog
Lawdog, would you check the tire pressure and tread condition on all four tires for us? What's the size of the Pole Positions? Do you have them on all four wheels or just the rears? How many miles on your car?

Sorry to be a pain but this is too good an investigative opportunity to pass up.

 

Ummm... folks... not to oversimplify, but (to repeat) -- "trailing throttle oversteer".

This will happen with any RWD car, but is far more likely with a car that is not tuned to push. So any car that is tuned for neutral handling (or for oversteer) will exhibit this trait. Most cars (even performance cars) sold in the US are tuned for understeer (for safety reasons).

The car was being driven near the limit given the situation (cold tires, near twice the marked speed) and throttle lift occurred. Given the severity of the response I would predict that the lift was not the sort of very gentle and subtle "breath off the throttle" but rather true (and sudden) lift.

Does anyone see any reason why the explanation needs to be more complex than this?

 

There are way too many variables to try to "learn" something from this accident. Unfortunately, most people aren't expecting to get into accidents so they don't make notes about many of the things that would be important. I think it's enough to note that it was cold out, the tires had not had a chance to warm up, and the driver lifted during a turn. I'm glad you're ok Lawdog and hope the S2K gets fixed good as new.

 

No I don't think so. It can seem pretty odious I suppose, sitting here dissecting someone else's prang,but it does seem like classic 'Lift Off Oversteer' which would be likely in those circumstances in any RWD sportscar, let alone one with the light weight and tendency to oversteer of the S2000. We all stand to benefit so much from this information. Interesting that in this case at least, they weren't stock SO2's. I'd love to see Lawdog post his tyre pressures, but correctly inflated tyres wouldn't have saved him from this one. Wrong pressures of course would have made the situation much more likely to happen.

In response to malachi

 

OK here's the data:

(1) Ambient temp- 68

(2) Air Pressure - Rears 30; Fronts 30.2

(3) Tread Depth - Rears 0.6 cm. ; Fronts 1 cm.

Absolutely dry road

 

I don't see this as a drivability issue. Ignoring the cold tires (which weren't the OEM versions, BTW), he still took the turn at nearly twice the recommended speed and lifted off the throttle in mid-turn. He didn't suddently spin while driving smoothly at near the recommended speed.

 

[QUOTE]Originally posted by Lawdog
[B]OK here's the data:

 

Besides the obvious issue of throttle lift during the turn, there's another factor that hasn't been mentioned: contact patch ratio front:rear.

Lawdog, I'm guessing that you were on stock wheels, with SO-2 Pole Positions, is that right? What sizes front and rear?

Unless you have aftermarket wheels, I don't think there's any way you have the stock 1:1.25 ratio, so you have reduced rear grip relative to front.

Ted