18/19 OEM Nismo wheels back to stock 18s
 

For about 8 years I've been running the OEM Nismo 18/19 255/40/18and 285/35/19. Tires finally bald so decided to put back on the stock 18s until I got some new rubber.
What a night and day difference driving on the stock 18s.The car transmission shifts wayy smoother, car is faster on acceleration and mileage went up 4MPG.. The ride quality is so much better as well. Yes I miss the aggressive look but damn. What surprised me the most is the automatic transmission shifts like butter now with the 18s.11 year old Z drive likes a beast again...

Nismo V3s are very heavy... 29lbs (wheel alone!) rear then add the weight of those 285s and you're at 55# or so. And of course, stock 18s, tires are much lighter too. I run light weight 19s and lightest weight tires I can find (Michelin PSS with total weight in low-mid-40s) and yet, my RPF1 with lightweight tires, around 41# total weight) is still more responsive. Tradeoff in grip and responsiveness (and like you said, probably mileage too.... )

Mic I agree with everything that you said... For now I'm staying stock and enjoying a quiet and more refining Z for a change.
One question though if you have any input? Larger wheels and tires also affects the performance of the auto tranny?The car shifts faster and smoother since the change..

Sure, more weight out back to get moving puts more strain on the entire drivetrain. You're not imagining the quicker shifting. Weight is the enemy of performance. But as I mentioned, everything is a tradeoff. You probably have a lot more grip overall with the Nismo setup but at the expense of slightly increased drivetrain wear and tear. Nissan did a great job with the car stock; but performance depends on how you want to use the car.

Thank-You Mic for your insights. For a moment I did actually feel like I was loosing my mind driving a stock Z again. I wish I could go back in time and slap myself for doing this nismo wheel upgrade lol.. Thanks again.