Rake Angle - the difference it makes!!!

[F355GTS]

Did a trackday on Saturday on a very short twisty circuit. Car was on Slicks, 8.2 x 22 rears on 8" rims and 7 x 20 fronts on 6" rims, rake was set to 15mm difference with circa 65mm under sump. To describe the car as oversteery was an understatement, however it was great fun 😬.

 

We went thorugh the rear tyres in an hour of tracktime and without any replacement slicks we moved hte front slicks to the rear (dropping the ride height at the rear by approx 25mm) and added some 185/60 21's on the front raising it by around 22mm so a overall 47mm adjustment in rake

 

The difference in grip (particularly rear) was staggering, the car must have been 3 to 4 seconds a lap quicker and although oversteer could be encouraged you really had to provoke it.

 

So in the end we were running with approx -28mm of rake ie the car was sat down at the rear which I was given to beleive was not the way to do it but I can tell you it works

 

 

 

Mark

[philwaters]

Interesting, but wouldn't the difference in grips levels front to rear also have had an effect - 21's vs rear slicks? I'd have thought that would have given understeer big-time.

 

Phil Waters

[Mike Bees]

Adjusting the rear height affects the way the DD tube 'steers' as the car rolls, and this has a big effect on the handling irrespective of rake. So what you've observed isn't just due to the rake change.

 

Mike

[F355GTS]

Phil

 

I'd have thought so too but it didn't

 

Mark

[Red SLR]

I increased my rear ride by about an inch last time I was on track as I wanted to have a play with the setup and took me 4 corners to spin LOL.

 

LeMans 2004 pics here

 

FREE SEVEN CHAThere

[Barry]

took me 4 corners to spin

Is that an improvement?

[Tyrone]

Mark,

I would agree with your observations. When I fitted the new AVO's I set the ride height as prescibed by Freestyle (as I thought), a few of the local guys commented on how low the car was at the rear, some suggesting there was negative rake, but it stuck to the road like glue. I increased the ride height at the weekend and it felt like it was all over the place. Didn't enjoy it on the road at all, adjustments will be made before next weekends Border blat.