smackboy1

I'm replacing my summer tires. I am fighting loads of understeer during autoX. I think it's the curse of AWD. I've been to a couple of autoX schools and I want to start doing some DEs. I have stock suspension and stock alignment.

If I switch to 235/40R18 in front will it decrease understeer much (keeping 285/30/R18 in rear)?

Is keeping 225/40R18 in front and upgrading the alignment a better idea?

Or switch to 235 in front now, and upgrade alignment later?

At this point I want to decrease the understeer but I want to maintain street drivability. Thanks.

BruceP

I'll be interested to hear what the autocrossers tell you, but when I was in that game I would have started by messing with tire pressures before I'd go switching things around and compromising streetability.

Heidster

If you are running stock alignment the front camber would be ~0 Deg. Having a good Porsche shop doing a "more aggressive" alignment would be a big help. You probably don't want a full track or autocross setup as that would compromise tire wear and a few other things. A good shop will know what you're going for and has had experience setting up other 996's for your goal. You will feel the results. The tire width increase will have a minimal effect, while playing with pressures will have a bit more.

I base the above on 15 years with my old SC and the adjustments and mods done for track/autocross.

Ray S

Switching to 235's in front will decrease understeer and will not hurt your street drivability IMHO. I run my Boxster front tires 10mm wider up front for that very same reason and I have not experienced any negs.

Additionally, I have 235's on the front of my 996 and have no clearance issues.

LiveNupe

I've run 245/35's in the front without clearance issues.

Ray S

I tried 245's on the front of the 996 and I had some slight rubbing on the front of the wheel liner on close to full lock.

LiveNupe

245/40 or 245/35??

Ray S

35's. My wheels are GT3 width and offsets, so that could be the problem.

The 235's work great.

auto-xr

I'm running 235s now and they are OK. I have a semi aggressive alignment and the car handles pretty good right now. I'm running 295s in the rear right now, so I think running at least 245 up front would even out the car a little more.

redridge

are your 295/30 on 10" wheel? Will 245 work on 8" wheel? TIA

auto-xr

I have 10" rears and 295 is the max that will work on them (I have 295/30/18). The max on my 8" rims is 245. If I go to 245s in front, ideal would be 245/35/18 otherwise 245/40/18 will work from what have read in various posts. The 245/35 is closer to 25" ideal of the car. I am running PS2s and will be sticking with them for now.

smackboy1

Is a switch from 225 to 235 in front even perceptible? How about 245?

auto-xr

There is a slight different from 225 to 235. The jump from 225 to 245 will be noticeable...less understeer.

gota911

I went from 225 front & 285 rear to 235 front & 295 rear PS2's, and I do notice a small difference. Can't comment on 245 front, since I have not tried that size.