When I get new tires, I am just wandering if I can fit a wider tire in the front without rubbing or changing my wheels. Has anyone done this before?

 

I have 235/40/18 Michelin Pilot Sport Cup and worked fine on the 18x7.5 OEM wheel...

 

Will the 4mm taller sidewalls have an effect on my acceleration? My goal is a more neutral balance in the corners, and less understeer near the limit. HDDP, did the 235's help reduce understeer?

 

I can't answer your question for the OEM set-up. When I installed the 235's on the front, I had already installed Eibach Springs, Koni Dampers, AMG sway bars front and rear and adjusted the camber & caster...

I can tell you that I ran the car on the track with the OEM set-up with only 800 miles on it and was immediately disappointed with the handling. It PLOWED through the corners and had alot of body roll. I immediately went on a mission to re-tune the suspension. I then ran it with new suspension with the OEM tires and it was really good, not perfect but...

What I'm saying is, a bit wider tire is not going to make the noticeable difference that you are hoping for. It really is a suspension thing with this car... For $1,000 you can make it handle like a dream, with $1,800 you can make it handle like a pseudo-racecar... And still keep the same tires...

 

Do you think the Crossfire, with suspension modification, can challenge a Lotus Elise on the racetrack in the corners?

 

I'm not SCCA guy by any means, but I'd say NO and here's why:

- Lotus weighs 1976 lbs
- its mid-engined
- suspension is tuned by Lotus

I'm sure if you listen to HDDP you can get the car to be ALOT better with his suggestion of springs, shocks and sway bars. Tires/wheels would help out alot too, but the suspension is key, like he said.

 

I have held my own on the track with a few Elise's, but it was driver, not car. I've got the suspension tuned to be pretty competitive with them, but they have much better acceleration out of the corners because of the light weight and lower center of gravity. The only way our car could be on par with the Elise would be with appx. 300 + hp. and a highly tuned suspension set-up.

 

No problem ~!
I changed wheels & tires into 18x8.5J (235/40ZR18), 18x9.5J(265/40YR18); Brabus mono V & Michelin PS2 without problem.

Too sticky and difficulty in front wheel control (due to bad road condition - too many trucks hear).

So, reinstalled OEM settings. But, the terrific down slope cornering performance hard to forget cause I live in mountain area. Maybe spring comes I seriously consider to change tires with engine power up.