Tire advice on 18x8 18x10

[winreboot]

Got a hold of 18x8 front and 18x10 rear wheels. I just need advice choosing tire size. I used http://www.miata.net/garage/tirecalc.html to see what is close to stock but numbers on computer and in practice might be two different things. (I don't know ) Any advice on the tire size appreciated.

I want to go with 225x35x18 front and 285x35x18 rear. I need the widest tires possible on the rear. It looks like the speedo would be 1.2-1.8% too slow, but going with 30 and living in NY metro area I would be asking for trouble. But maybe 30 is the way, I don't know. Just need advice what is acceptable/drivable.

Thanks,
Dave

 

[nsxtasy]

I would go with 215/35-18 front. With the 225/35-18, some folks have reported rubbing on the fender well liners, while others haven't.

I wouldn't go with a 285 rear. That means a "stagger" (difference between front and rear treadwidth) of 70 mm, compared with a stock stagger of 20 mm ('91-93), 30 mm ('94-01), or 40 mm ('02-05). The stagger can affect the handling and you don't want it to be too far from stock. I would go with a 265/35-18 rear.

The 265/35-18 would still make the speedometer off (slow) by 1.8 percent on a '91-93, 2.4 percent on a '94-01, and 1.1 percent on an '02-05. But that's better than the figures of 4.0 percent, 4.6 percent, and 3.3 percent that a 285/35-18 would give you. (I don't know how you calculated 1.2-1.8 percent...)

 

[NRG]

Man..did I ever tell you how knowledgeable you are? You da man!

I would go with 215/35-18 front. With the 225/35-18, some folks have reported rubbing on the fender well liners, while others haven't.

I wouldn't go with a 285 rear. That means a "stagger" (difference between front and rear treadwidth) of 70 mm, compared with a stock stagger of 20 mm ('91-93), 30 mm ('94-01), or 40 mm ('02-05). The stagger can affect the handling and you don't want it to be too far from stock. I would go with a 265/35-18 rear.

The 265/35-18 would still make the speedometer off (slow) by 1.8 percent on a '91-93, 2.4 percent on a '94-01, and 1.1 percent on an '02-05. But that's better than the figures of 4.0 percent, 4.6 percent, and 3.3 percent that a 285/35-18 would give you. (I don't know how you calculated 1.2-1.8 percent...)

 

[ANYTIME]

I would go with tireracks recommendations of 235/35-18 and 255/35-18 on 8's and 10's on an NSX.

 

[SNDSOUL]

I would go with tireracks recommendations of 235/35-18 and 255/35-18 on 8's and 10's on an NSX.

235/35/18 would definetly rub on the front of an NSX, especially if it is lowered at all. Do the 215/35

 

[RP-Motorsports]

A 235 will rub a bit, and you need a high offset +43mm to get them to work. You need to tell us your rim offsets to also judge what will work, and what won't.

 

[RP-Motorsports]

I would go with 215/35-18 front. With the 225/35-18, some folks have reported rubbing on the fender well liners, while others haven't.

I wouldn't go with a 285 rear. That means a "stagger" (difference between front and rear treadwidth) of 70 mm, compared with a stock stagger of 20 mm ('91-93), 30 mm ('94-01), or 40 mm ('02-05). The stagger can affect the handling and you don't want it to be too far from stock. I would go with a 265/35-18 rear.

The 265/35-18 would still make the speedometer off (slow) by 1.8 percent on a '91-93, 2.4 percent on a '94-01, and 1.1 percent on an '02-05. But that's better than the figures of 4.0 percent, 4.6 percent, and 3.3 percent that a 285/35-18 would give you. (I don't know how you calculated 1.2-1.8 percent...)

I actually figured out different front/rear difference than that???

91-93 rears 45.4mm taller than fronts
94-01 rears 27.9mm taller than fronts
02-06 rears 32.0mm taller than fronts

94-06 pretty much consistant, but for the 91-93, the rears are also consistant with 94-06, but the difference is the fronts are way shorter.

Or are you talking about width? which would not make a difference in speedometer error or TCS.

 

[nsxtasy]

I would go with tireracks recommendations of 235/35-18 and 255/35-18 on 8's and 10's on an NSX.

I really doubt that Tire Rack would have recommended 235/35-18, since it WILL rub, big time. Perhaps they actually recommended 215/35-18?

I actually figured out different front/rear difference than that???

I am talking about the outer diameter of the tire. Most tire calculators (such as this one) deal in percentage differences, rather than millimeters. The TCS tolerance is also specified in percentages.

I am quoting the percentage difference between the 18" rear tire size being proposed, and the stock rear tire size. That percentage is the error in the speedometer/odometer that will result from using non-stock rear tire sizes. Here are the sizes being discussed here:

'91-93 stock 225/50-16 0.0 percent
265/35-18 +1.8 percent
285/35-18 +4.0 percent

'94-01 stock 245/40-17 0.0 percent
265/35-18 +2.4 percent
285/35-18 +4.6 percent

'02-05 stock 255/40-17 0.0 percent
265/35-18 +1.1 percent
285/35-18 +3.3 percent

I'm not sure why you're quoting the difference between the front size and the rear size; that has nothing to do with speedometer/odometer error, only with TCS tolderances, and the TCS should work with 215/35-18 front and 265/35-18 rear on any year NSX.

 

[RP-Motorsports]

I missunderstood your "stagger" in your previous post. I thought you were talking about TCS issues. You were actually talking about tread width versus oem, which is really a non-issue with speedometer error or TCS, but in handling as you stated. My bad.

 

[winreboot]

OK, now I have an idea what to get. I'm going to pick up 215/35-18 front and 265/35-18 rear. Thank you all.