This week I went to 245/45 on all corners with my 18x8 wheels. My commute is mostly country roads and at all speeds up to 60-65 mph I didn't see a flicker from the TCS/VDC/ABS or anything. Took it out on the interstate today and at speeds up to 85 mph the car was steady and not a sign of any indicator lights coming on. There is a bit of a change in steering -slightly more sensative - but that's expected with a bit more footprint.

Interesting comment from the technician who put on the tires - "From the wear pattern on the fronts, you seem to need an alignment." Duh. The Nissan TSB specs kept the cupping noise away for about 16,000 miles but eventually it was there again.

At least now I can rotate tires and maybe make them last more than 20K.

 

low tire pressure will turn them all on

 

I have 255/40/17 all around ... will my car blow up?



I drive hard on the car daily and have found that the VDC and ABS both react like it should and I cannot tell any differences. Maybe I am not sensitive to changes. The only time that I see the slip light come on is when I am trying to get the rear-end to come around.

I have also driven on 235/30/19 front and 255/40/17 rear for a couple of days and seemed fine.

 

Regarding the Sport Compact Car Project 350Z article:

I went to college with the guy who wrote it, and I can tell you straight out that his attitude about such things is that if you're not able to tell by feel what's changed about the car with a swap like that, you shouldn't be doing it.

He's also a guy who's not afraid to try a suspension mod, spin out a few times on the track, and shrug and say "Maybe that wasn't such a good idea after all." That doesn't mean he'll drive that car out onto the street.

My opinion is that if you want to do something like put the same size tires on all four wheels, you'd better (1) be able to do the swap yourself, and undo it if need be, (2) be able to read how the car's handling has changed and decide for yourself, sensibly, whether it'll be safe and (3) make a careful test drive to decide whether to keep it that way.

-- Mark