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New wheels and tires

12 March 2001
I ordered new wheels and tires. Sizes 265-35-ZR-18 and 215-40-ZR-17. When I set them next to the oem wheels on the car to see how cool they would look I noticed they are 1-2 inches taller. Is this going to mess with my TCS or speedometer?
Originally posted by steveny:
they are 1-2 inches taller. Is this going to mess with my TCS or speedometer?

Your sizes are fine for TCS.

They WILL cause your speedo to give low readings (actual speed > greater than indicated, assuming indicated is correct). A ratio of your new rear diameters to your OE ones.
The outer diameter of the front size is 0.7 inches (3.0 percent) bigger than the '91-93 stock size, and of the rears is 0.4 inches (1.8 percent) bigger than stock. This 1.8 percent difference is also the factor that your speedometer will be off in comparing new tires of this size with new stock size tires.

However, the difference between a tire that's new (usually 10/32" tread) and one that's completely worn down to the treadbars (at 2/32") creates a difference of half an inch in diameter. Assuming that you are comparing worn stock size tires with new larger size tires, this can mean that the outer diameter is indeed around an inch bigger - but half of the difference is caused by tire wear, not tire size.
I just switched to 17/18 with 265/35 rears as well. I've noticed that the car feels less powerfull now... and the handling seems crappier.. but it could just be the tires. I switched from:

F 205/40ZR/16 Nitto 555
R 245/40ZR/17 OEM Yokos
using OEM 7 spoke rim


F 215/40/17x7.5 Kumho Excta Supra
R 365/35/18x9 Kumho Excta Supra
Volk TE-37s

The handling is definitely much looser... even after I reverted to the same alignment specs.
I just switched to 17/18 with 265/35 rears as well. I've noticed that the car feels less powerfull now... and the handling seems crappier.. but it could just be the tires.

This sometimes happens when you change more than one variable at the same time. You don't know which one was responsible for the change. (My guess is it's the model of tires, but I'm just guessing.)

Well, if the stock ones were on the car, and it was on the ground, then of course they looked somewhat shorter due to the flat spot on the bottom. I assume you took that into account when you said 1-2 inches?

My earlier comments were based on the outer diameter of the tires when they are NOT mounted on the car. sjs is correct in noting that wider tires deform less when they're mounted on the car, so that the distance from the top of the tire to the ground is less due to that factor alone. This would be in addition to the other two factors I mentioned in my earlier post.
The tires are probably to blame for the crappy handling.

-- Chris


www.ScienceofSpeed.com - Click for more info
www.NSXClassifieds.com - The internet's only exclusive NSX Classified site!
I run the same tires on my -94. i just changed my really worn out rears, Good Year F1 to Bridgestone Potenza 03 (for rainy Swedish summers) and noticed a huge difference in acceleration. I was assisting when we changed the tires, and the weight difference between the new/worn was incredible. T guess after you have driven it for a time, the nice acceleration will occur again.

Enjoying life at 8.000 RPM
After I had posted I realized that they were not that much taller because the oems were on the car. I hadn't taken that into account. You guys are right. Its only about .5 to 1 inch difference. I will repost, after I get them mounted, to let everyone know about the acceleration difference.
That's exactly the problem,those Kuhmos are not any good, cheap tire.
The only Kuhmo tire that is more or less
acceptable are the shaved ones.

Crazy4Cars Racing

[This message has been edited by pronto3000 (edited 13 July 2001).]
This has become a nightmare. The shop where I bought the Wheels machined the center bore wrong. They inverted the front and rear. SO...the wheels and tires that I waited two months for DO NOT FIT.. For the rear they want me to use a plastic ring to space out the difference, included with the wheels, so they knew the wheels were wrong when they sent them out. For the front two they want me to ship them back to CA so they can remachine them. I don't think so. I don't think these guys know what they are doing. Can anyone make a recommendation on where to get wheels. The tire rack I know of but they don't have the style I am looking for in 17-18. Why would these guys send out plastic spacers? They can't be safe.
Sorry to hear about your misfortune. What you are talking about are hubcentric rings, not spacers. Hubcentric rings are simply meant to center up the wheel properly when the lug nuts are installed. Once the lugs are seated, the hubcentric ring has no other function. Although I would recommend against plastic if you are going to be doing any spirited braking or track events (they are available in aluminum as well, hubcentric rings aren't evil.

-- Chris


www.ScienceofSpeed.com - Click for more info
www.NSXClassifieds.com - The internet's only exclusive NSX Classified site!

Call Vick at Discount Tire. Very knowledgable on NSX fitment. Many more wheels available then the site has room for.
Discount Tire Center
10707 Valley Mall
El Monte, CA 91731

Business Hours:
Mon - Fri: 8am - 6pm
Sat: 8am - 5pm
Sun: Closed

Tel: (626) 579 -1182 (888) RIM - ALOT (888) 568 - 2746

Email: [email protected]
So, I ordered another set of wheels. This time the offsets are wrong and the fronts don't fit. Has anyone else had this many problems getting wheels or am I just jinxed. I even faxed them the entire specs. from the FAQ here. I have learned a great deal about wheeels in the last two months so I guess its not all a loss.
Who are you dealing with or what wheel store is it.

Steven 91 Blk/Ivory
The first place was Victoria wheel and tire. I would recommend this place to no one. They lied, they were rude, they have NOT refunded my money (They have had their wheels back for a week now). The second place was discount tire direct. They have been good about it up until this point. I did have to get a little nasty with them on the phone to get them to send out another set without waiting to get the original set back.
Well I finally got a set that fit. WooHoo! I have some questions though. I went with 17 - 18 set up. They definately don't feel like the factory setup. They are squishy feeling. Not as tight as OEM. Is this normal or is there something I can do to correct it? BTW- I went with the Dunlop SP Sport 9000.
You can play around with the tire pressures to see if that helps. However, even if that improves it a little, the SP9000 tires are not as responsive as the OEM tires.
From what everyone has said, the SP9000s do feel squishy, especially when they are new and particulary when compared to the "razor sharp" feel of the OEM tires. That's just how they are. You can try to compensate some with tire pressure, but make sure you don't over inflate so much that you degrade handling or cause them to wear unevenly.
I will try to post some pics real soon. As for the tires what feels as good as the OEM tires but is available in 17-18. Are the original compound tires available in 17-18. I am loving the look of the new wheels but I am extremely disappointed in the handling changes, enough to trash the tires and replace them. I read through the FAQ's tires section. I would like to get some opinions from some of you directly.
Are the original compound tires available in 17-18.


(There's a 17" size but it's designed and sized to be used on the rear, not on the front.)
I called discount tire direct today. they are going to exchange the tires for pilot sports. Are these going to feel any better than the sp9000 tires I have now? The difference in price is $268.00
Well they called back today while I was out. They said that the pilots are on national back order. What would be a better choice than the sp9000's. Reguardless of cost what will feel as good or close to OEM tires.