[BigShow1960]

I was on the Main Wild Horse Pass track last weekend. This was my second time on this trak, two days last year and two days this year. There a decreasing radius turn after a long straight (139 MPH). Last year I could floor the car at the apex. This year the rear end stepped out on the first lap and a few others. I had one of the instructors drive it for a few laps, he thought it was loose as well. I kind of lost confidence in the car in the turns and didn't push hard. There were a number of other 1LEs out there, some of the better times were 3 s faster than my best. I'm sure that two of those drivers are more experienced and better drivers.

I added the OEM wicker bill this year. Differences from last year, 10 degree or more cooler day. Last year the tires were new, 2,000 street miles. This year the front tires were pretty new, I think one prior track day and some street mies. The rear tires are at end of life, last track day.

Could the difference in front to back tread depth impact the handling. Could the difference in tire age impact the handling? I'm sure temperatures made a difference, but there were other cars out there without this issue.

[asrautox]

Originally Posted by BigShow1960

The rear tires are at end of life, last track day.

Here's your answer..

[Jimbeau11]

I would say new(er) tires on the front and old (end of life) tires on the rear magnifies the over-steer (edit) issue. Many tires lose their ability to provide maximum grip long before the tread passes the wear bars and if you have good grip with newer tires on the front and low grip with older tires on the rear you're definitely going to notice a "loose" condition.

[FNxR3DNECK]

Originally Posted by Jimbeau11

I would say new(er) tires on the front and old (end of life) tires on the rear magnifies the under-steer issue. Many tires lose their ability to provide maximum grip long before the tread passes the wear bars and if you have good grip with newer tires on the front and low grip with older tires on the rear you're definitely going to notice a "loose" condition.

This right here, except I think you meant to say over-steer.

The 1LEs are engineered with a slight bias toward under-steer which makes them very easy to control right up to the limit. I would say your over-steer issues on that day is 100% attributable to the tires, new fronts=more grip, old rears=less grip, more front grip than rear grip=over-steer, case closed. I would say it's time for some new rears and you will go right back to enjoying your car on track with full confidence!

[Jimbeau11]

Originally Posted by FNxR3DNECK

This right here, except I think you meant to say over-steer.

The 1LEs are engineered with a slight bias toward under-steer which makes them very easy to control right up to the limit. I would say your over-steer issues on that day is 100% attributable to the tires, new fronts=more grip, old rears=less grip, more front grip than rear grip=over-steer, case closed. I would say it's time for some new rears and you will go right back to enjoying your car on track with full confidence!

Yup, good catch. Under-steer is the one I don't like so it's always first in mind!

[BigShow1960]

Thanks guys. I have another set of rims and tires that I'm dedicating for track use. I would have used them but I damaged a tire and bent a rim going two wheels over on the curbing, the new rim/tire shipped the Friday before track day. The dedicated track setup is squaring - 305s all round which might lead to oversteer but I didn't feel like I experienced that at on the Bondurant course.

[FNxR3DNECK]

Originally Posted by BigShow1960

Thanks guys. I have another set of rims and tires that I'm dedicating for track use. I would have used them but I damaged a tire and bent a rim going two wheels over on the curbing, the new rim/tire shipped the Friday before track day. The dedicated track setup is squaring - 305s all round which might lead to oversteer but I didn't feel like I experienced that at on the Bondurant course.

It may "feel" like it's over-steering with the 305 squares but in reality it should be quite balanced, I run 305 square for Autocross and used them for two days at VIR back in May and it felt great, the biggest thing you will notice with that setup is improved turn-in response, it's GREAT! I'm going to be running 305 RS4s next year (*cough* Provoste *cough* lol) and can't wait to see how they perform compared to the RE71s

[BigShow1960]

My track set are the RE71Rs. I wanted RS4s but they were out of stock.

[AZ_1LE]

Hey, I saw you there, I was there helping my friend run in the enduro event on Sunday.

I just went through the exact same thing as you. Car was loose as hell at Inde Ranch, got new tires, car is back to normal. It got to the point where I could spin the tires in 2nd gear if I just stepped on it, and they still had plenty of meat on the outside shoulders.

Get new tires, trust me