The Ford GT was designed with geometric features to minimize over steer accidents, it has roll under steer built into the suspension geometry, ridiculously small front tires and spring rates that promote under steer. These things push like pigs in almost all situations, Mark McGowan can verify that if you don't believe me. The exception is when the rear tires are spinning at a rate way beyond road speed then the slightest resistance from the front will send it spinning off the road because there is No Rear Traction in any direction. The cause of the loss in rear traction could be throttle angle, ice, sand, water etc. but the result will not be good if road camber, steering angle or a multitude of other conditions are present. I agree this can happen to the most expert of drivers but usually does not, it is usually the drivers that don't recognize the feel of the rear tires breaking traction in time to react.
I changed my spring rates from 200 lb/" front to 450 lb/" and rear from 280 lb/" to 700 lb/", I also changed the rear toe curve to eliminate 60% of the roll under steer and increased the front tires size from 235 to 265 and now the car is very responsive but a little on the twitchy side. The point is, the car is very driver friendly as designed but not all that good in terms of responsiveness because they wanted it that way. If the car had 4 wheel drive or stability control or even traction control or less power it would be less prone to these issues but then it would not be a Ford GT it would be a GTR. The engine makes lots of torque low in the power band and can spin the tires with ease if the driver lets it. The key is not to let it bite you in a situation you are not sure about, especially on public roads.
Hi Guys
I believe this to be a very accurate statement. 99.9% of road cars are designed to under steer.
I was asked to comment on this subject…
In my opinion:
The issue with the GT is not an "issue" with the GT. It is the same with any high performance car. Yes the GT has a mid-engine platform that helps center the mass and CG of the car... the closer the mass of the car is centrally located, then the less rotational inertial the car has. This means it will turn better. This also means it will spin about its axis better. Much like an ice skater that has their arms out while spinning (example of a car with its weight more outbound from the center of the car) and then the same ice skater once they pull their arms in (example of a car with more of its mass centralized). I realize that is more an example of conservation of momentum but I think it paints a good picture of rotational inertia as well.
I could be wrong but I'll bet that of most of the GTs that get wreck, most high performance street cars in general, are from compression braking. Either lifting while turning or getting the rear end out under power and then lifting. These cars make significant power, this means that it will also make significant "negative" torque when you lift the throttle. This negative torque acts just as if you hit the rear brakes if the clutch is engaged. Imagine what would happen if the rear of your GT was hung out and you then mashed the brake pedal but only the rear brakes engaged. This braking effect of the rear tires will "slingshot" the car back the opposite direction that it is stepping out (similar to a motorcycle high side). The car will go back to being pointed straight but will do it with so much speed that the rear will just keep going initiating the full spin of the car.
GTs will "step out" for many different reasons. Spinning the tires on a crowned road will cause the rear to "slide" down the crown. A bump where one tire retains contact and tractive force and the other does not, or driving over water or something else slick with just one wheel... this causes the one tire that has traction to power steer or "yaw" the car... it's a similar effect to getting hit from behind in one taillight. The power is only being applied to one side of the car. The diff will try to transfer power to the wheel with traction in this instance too, exaggerating the issue. Exiting a corner and spinning the tires while still laterally accelerating is an obvious one as well as a steering input during heavy acceleration.
I personally chalk most wrecks up to:
1. Power wheel spin followed by a "step out", followed by a throttle lift, followed by an instantaneous over steep and vehicle spin
2. A lift in cornering or at a crest
Ths GTs have no:
Boost Control: Nothing to limit power for the gear it is in leaving it up to the driver to modulate power in 1st and 2nd.
Traction Control: Nothing to aid the driver in an instance of misjudgment in the application of power or a surface irregularity that induces wheel spin.
Stability Control: Nothing to aid in recovery of the yaw effect (braking outside tire to prevent spin)
Add all this up with:
1. Novice Driver
And or
2. Bad weather / road condition
And you get many wrecked GTs.
The hardest thing for a driver to learn in my opinion is to not lift if the back has stepped "way" out. Needed response is opposite of instinct. A little step out and catching it soon, yes lift, however... if it is way out... if you lift, you're going around. The proper approach is to reduce but modulate the power and essentially drift the car until control is regained. Much easier said than done. Some instances on the street or track there is no room for this and you’re screwed regardless of skill. I'm not a fan of "drifting" but a drifting school in my opinion does wonders for drivers learning to control power induced over steer.
Just my opinion as to why so many GT’s get wrecked.
Cheers gentlemen!
P.S. Chip's story reminded me of something one of our pro drivers once said to a spectator. Our driver was stating how hairy a particular higher speed corner was and the importance of the proper line and setup coming into it. The spectator asked how fast he was taking that particular turn. Our driver stated he was a little over 100 mph through the corner. The spectator responded, "100, that's not that fast." Our driver smiled and said, "When things are fine, a hundred mph isn't that quick... but trust me, when things aren't fine… 100 mph is damn fast!" Spinning backwards at 100 is a lot quicker than glued to the road in a straight line at 100.
