Just picked up an 09 sport diamond grey metalic that i will be slowly setting up for b-stock. Have been autocrossing AP1 and AP2 S2000 and needed something with a backseat(damn baby seats), have been reading up lately and had previously driven Mark Allen's 04. Was originally looking for a used 05-06 but got such a great deal on the 09 that i couldnt pass it up.

So for starters gonna start of with the new TR Motorsports wheels at 20lbs and under $600 they seem like a steal.

Got two sets of used tires. gonna try 285 kumhos first and then switch to 245 hoosiers to see the difference. Will start with stock bar and then maybe modify and alignmnent. First event in two weeks, well see how it goes.

Anything i might be missing. What is everyone running for tire pressures?

Ill be sure to post up some pics soon

Sacha

 

I don't do autocross, only track driving so I can be off, but:
285 sound very wide to me. The 225s we have stock gives plenty of grip. I'm just worried you will lose exit speed of turns since you are dragging heavier rubber around.

Then again, it might be possible acceleration is less important on autocross compared to a several km track where you have 800 meters of straight.

Personally i run OZ Ultraleggera 17" rims for weight running 225/45/R17 Toyo R888. The smaller tiredimension acts as tighter geared car which gives me acceleration benefits. I like it alot!

 

Sacha,

The biggest thing you're missing are koni shocks. These aren't a must, but as they are a low gas pressure shock they will lower the ride height of the car by ~1/2". They also help the car transition faster as the rate the car rolls is reduced. Stock swaybar works well, but some like a slightly stiffer bar like the Mazdaspeed FSB or Hotchkis MX-5 bar.

Otherwise, get a good alignment. Reduce front caster, max out front camber and run slightly more in the rear. e.g. -1.5 camber front, -1.7 camber rear.

PerSmitt, per scca stock class rules he'll have to run an 18x8" wheel within a 1/4" offset of the stock wheel.

Btw, TeamRX8 has tried a 225 tire, but now runs a 295. Most go with the 245 A6/V710, or the 285 Hoosiers. There is also a new 255/35/18 Hoosier that's looking mighty interesting...

 

most run 245

with wider you'll lose exit speeds

 

I got a free set of 285 and want to try those out first. My train of thought also is that i will need all the diameter i can get to compensate for the shorter gear

 

I hope you have a very talented tire guy...the 285 Kumho is a beotch to get on the 8" rim...

 

Been there done that. Used to work for a wheel/tire company, now work for a dealer where we have a variety of different tire machines

Sacha

 

even with the shorter gear, 285 seems much. i would say 265 would be perfect. but try out the 285 and tell us how it feels. 225 is bearable, more would be nice (stock) i'm debating between 275 and 245.

 

Videotape it. I want to see it done. Make sure to have the volume working so that we can hear all the colorful language.

Getting the 285's Kumho's on an 8" rim is an ancient Tennesseean secret.

I also saw the TR wheels. They are a nice inexpensive alternative.

 

The new 255/35/18 A6's are actually a 265. Here's a post by Harvey (Zoom4Three) about them:
One other thing to point out - you lose almost no gearing with a 285/30/18 compared to a 245/35/18 (by my calcs the gearing difference is less than 1%). The biggest thing that'll hurt you when you run that size tire in a V710 is weight - those bad boys are very heavy (at least 2-3 lbs heavier than the comparable A6 size).

I would agree with always.anthony on the 265 size being perfect for our cars. That's why Shawn and I will be switching to these once we use up our set of 245 V710's from Nats.

 

Hey Sacha,

I think I used to go to the same tire company you used to work for...they were the only ones in town that could actually mount the 285's on the 18x8 for me (My 350z). Do you know of another place around?

Thanks,

JR

 

Mount them on a slightly wider wheel first, like 9", then they go on fine, having them warm helps a bunch too

free is free, but for the K tire I recommend sticking with the 245/35 if you're buying, the contact patch on a 285 has too much curvature IMO, I don't like them

 

Do the Koni's fit on the new 09?
Has anyone weighed the new 09 wheels?