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Optimal size tires for 17X8 and 18x10 wheels?

Joined
5 December 2016
Messages
75
Hello all!
I hope everyone at NSX Prime and your families are all doing well!

I recently purchased a set of Tecnomagnesio wheels in 17X8 and 18X10 and I'm trying to determine what the "optimal" size is for tires on wheels with that width. Being that my 96' NSX-T only has headers, high flow cats and an exhaust, I think it's fair to say that I'm still making less than 300hp and as I'm trying to limit un-sprung weight and rotating mass, I'd like to go with the narrowest tire that would fit in the rear while not having a "stretched" look. I currently have 215/40-17's and 255/35-18's on MITA 7S wheels (Which by the way are beautifully made wheels and I am VERY happy with) and my personal opinion is that those tires are pretty much optimal both aesthetically and for grip, but I don't think a 255/35-18 will fit correctly on a 10" wide rear wheel.

Not to complicate matters, but if I'm going to have to go with a wider rear tire I'd like to widen the front by an equal measure as I am happy with the current balance and don't want to increase understeer.

On a similar subject, I have a question for those who have 200 or less treadwear tires. As I'm only putting MAYBE 3000-5000 miles a year on the car I'm not concerned about tire life but I AM concerned about picking up gravel and getting paint chips. Has that been an issue for you guys?

As always, I appreciate any input or suggestions.
 
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265-285 work fine on a 10 inch wheel. My paint is worn /pitted from years of R compound rubber...oh well patina..
 
Yeah, I suspect I'm stuck...

Thanks for the response sir. I was confident that 265's would fit and was sure 275's would, but I'm trying to keep them as narrow as possible. I really wish 255's would fit but I suspect they'd have a "stance nation yo" stretch.

It looks like I can do a 215/40R17 front and a 265/35R18 or 275/35R18 rear, I can do a 225/40R17 with a 275/35R18 or (Correct me if I'm wrong) I can go with a 235/40R17 with a 275/35R18 rear. Again, I'm trying to keep the unsprung and rotating mass as low as possible. Has anyone had any experience with a 225/40R17 front?
 
Try finding a good tire in 225/40/17:wink: the 235 fronts are a popular track size which I use. The tire being taller and wider will rub on the rear inner wheel well polishing up the aluminum. You will have to remove the front plastic fan shrouds..
 
Who knew tires would be such a dilemma??

Try finding a good tire in 225/40/17:wink: the 235 fronts are a popular track size which I use. The tire being taller and wider will rub on the rear inner wheel well polishing up the aluminum. You will have to remove the front plastic fan shrouds..


Well, you're right about that but that's true with pretty much ALL of the tire sizes we're talking about. I did find that the Continental Extreme Contact Force is available in the 225/40R17 and 275/35R18 combination. Admittedly that wouldn't be my first, second or even third choice, but between that, the Direzza III's RT660 and RT615K+ that may be a viable choice but was curious to see if anyone were familiar with those tires or more importantly, running a 225/40R17 front tire.

As always, any input is sincerely appreciated!
 

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You can definitely stretch a 255 wide tire on 10 inch rims. Some tires run a bit wide to start with... I'm using 215/40/17 + 255/35/18 on my setup with 8" fronts, 10" rears ('98 NSX, so same size match as yours).
 
I’m super curious how the Conti extreme 225/40/17 fit on an an 8” wheel. If you get them, please post pics! I really want to try them at some point.

The RT660 are pretty wide for their size. The 215s have zero stretch whatsoever on a 7.5” wheel, so will have only a slight amount on an 8” wheel. The RT660 275/35/18 will fit perfect on your 10” wheel in the rear. I have them on 9.5” rears and they are wider than the wheel.

Advan AD08Rs are also pretty wide and the 215/40s work well on an 8” wheel. $$$ tho

Check out the specs on tire rack for a given tire and size. The tread width, section width, and measured rim width can give you a good idea of how it’ll fit and how each tire differs from the others in the same size.
 
Advan AD08Rs are also pretty wide and the 215/40s work well on an 8” wheel. $$$ tho
That's precisely what I was using on my 17x8" / 18x10" setup (215 front, 255 rear) but they are now discontinued at least in Europe. Hoping that the Goodyears Eagle F1 A6 also run a bit wide...
 
18x10 +35 265/35/18 rt660
17x8 +38 215/40/17 rt660
Volk te37 saga s plus
Tires are much wider then others in same size no stretch at all nice shoulder. Picture is from about a month ago.
 

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Nice choice! 215/265 would be my ideal size for that setup. You could do 215/255 or 235/275 or even 215/275 but I wouldn't do 235/265 or even 235/255 personally speaking.

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I was very happy with 215/40/17's on 8" fronts, and 275/35/18's on 10" rears.

It kept the front (manual) steering fairly light, and the 275's made the speedo error essentially zero.

Plus, that combo looked great on the car!
 
I am assuming the widths would be the same but the AR slightly smaller if I am running 18x8 and 19x10s?
I use this calculator all the time for comparison on sizes:

However note this is basically assuming different sizes of the same make/model tire. I've found out the hard way that every tiire manufacturer has their own interpretation of size. I'm running 265/35-18 on my 10" rear but found out my tire width is actually a full inch more narrow than other manufacturer tires of the same size. You would have thought 265 wide is a static measurement, it's not like the definition of 265mm changes.
 
Do you have any problems with tires size 215/40R17 (front tires) rubbing on the inner fender liner, especially when you turn the wheels? I just changed the tires from 215/35R17 to 215/ 40/R17 and I have noticed the tires rub on the inner plastic liners.
 
Do you have any problems with tires size 215/40R17 (front tires) rubbing on the inner fender liner, especially when you turn the wheels? I just changed the tires from 215/35R17 to 215/ 40/R17 and I have noticed the tires rub on the inner plastic liners.
I do not have any rub using that front tire size on Kumho Ecsta PS31 so that is a 7.2" tread width tire. Check the tread width on your specific tire brand/model.
 
For those running the RT660, what the pressures are you running? I've noticed that they like to grab at transitions in the freeway.
 
Do you have any problems with tires size 215/40R17 (front tires) rubbing on the inner fender liner, especially when you turn the wheels? I just changed the tires from 215/35R17 to 215/ 40/R17 and I have noticed the tires rub on the inner plastic liners.
Depending on the tire maker, they will rub. You just have to remember to back off full lock turns...
 
I was very happy with 215/40/17's on 8" fronts, and 275/35/18's on 10" rears.

It kept the front (manual) steering fairly light, and the 275's made the speedo error essentially zero.

Plus, that combo looked great on the car!
i am running the same size wheel combo and it became very hard to find tires. I am located in Ohio and i see you are in Michigan. did you ever run all seasons ? or always summer performance? i do daily my car so i drive in rain and i dont want to be uncomfortable with summer performances. oh forgot to mention, i have a stand alone ECU so i dont have TCS.
my car is also insanely low, which i will be lifting maybe an inch/half. so maybe i can fit 215/45/17 in the front ? i realised that it is easier to find 215/45/17 rather than 215/40/17. my current setup is 215/40/17 275/35/18
right now i have pirelli p zero nero all seasons from 2017, which i cant find anymore
i dont have fender liners or covers, i am thinking of installing them too
I would appreciate the help from everyone about tire recommendations.
pics below for help
 

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i am running the same size wheel combo and it became very hard to find tires. I am located in Ohio and i see you are in Michigan. did you ever run all seasons ? or always summer performance? i do daily my car so i drive in rain and i dont want to be uncomfortable with summer performances. oh forgot to mention, i have a stand alone ECU so i dont have TCS.
my car is also insanely low, which i will be lifting maybe an inch/half. so maybe i can fit 215/45/17 in the front ? i realised that it is easier to find 215/45/17 rather than 215/40/17. my current setup is 215/40/17 275/35/18
right now i have pirelli p zero nero all seasons from 2017, which i cant find anymore
i dont have fender liners or covers, i am thinking of installing them too
I would appreciate the help from everyone about tire recommendations.
pics below for help
Our NSX's are Summer-only cars, so we only run high performance Summer tires on them. Our only concern with this strategy is that if the outside temp is below 40*F many tires aren't designed to be run when it's that cold out.
Our red NSX ran the 215/40/17 275/35/18 combo very well while only being lowered 7/8" all around (Bilsteins w/stock springs on the lower perch).
The purple NSX has wider front fenders and is lowered around 1.5" on KWV3's, and even then did some rubbing up front with 235/40 17's and 25mm spacers.
I hope that helps...
 
Our NSX's are Summer-only cars, so we only run high performance Summer tires on them. Our only concern with this strategy is that if the outside temp is below 40*F many tires aren't designed to be run when it's that cold out.
Our red NSX ran the 215/40/17 275/35/18 combo very well while only being lowered 7/8" all around (Bilsteins w/stock springs on the lower perch).
The purple NSX has wider front fenders and is lowered around 1.5" on KWV3's, and even then did some rubbing up front with 235/40 17's and 25mm spacers.
I hope that helps...
That does help thank you. I may lift my car up a little bit and find better options with 215/45/17 for front. I just cant think of not driving the car when i see outside dry or sunny even with 35’F 😄
 
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