Unofficial Big-Wheel Thread: 18/18 and 18/19 - the future for NSX tire sizes

[docjohn]

I like the debate.....I will pray that Dave will someday be able to drive his car without tearing itself to pieces:biggrin:

 

[bngl3rt]

If you want the best, most modern street tires that deliver near R-comp performance, ride quality, etc... (Technology thats newer than 5 years) there really are no options other than 225/40-18. To make ABS/TCS happy you need a 275/40-18 or 275/35-19 ish size.

A 225/40-18 fit under a stock fender but you probably have to remove your fender liner. A few of us are going to these sizes to define what is needed to make these sizes work if you want one of the tires listed on post #111

I am a track rat without a tow vehicle so the best tires that can drive to, around, and home from the track is my idea of a good one (as I cannot carry a 2nd set of wheels).

You guys are pioneers and what you are doing is great for the community. Thank you. Looking forward to the results of your experiment.

 

[docjohn]

I am a track rat without a tow vehicle so the best tires that can drive to, around, and home from the track is my idea of a good one (as I cannot carry a 2nd set of wheels).

You guys are pioneers and what you are doing is great for the community. Thank you. Looking forward to the results of your experiment.

My simple answer for you is ra1 235/40/17 on a 7.5-8 inch front and 275/40/17 or 35/18 on 9.5-10 inch rear...I've been doing that for 12 years.

 

[Shaylord]

Well besides the GT-R wheel as Dave mentioned, here my second contribution to this thread. I have made a spreadsheet with all three OEM tire sizes, their width, radius, diameter, circumference, sidewall, rotation ratio, and front to rear splits. I have also added some 12+ tire sizes that people run now, or have suggested. This is still a work in progress, but I created a google.docs for it so anyone can view it.

https://docs.google.com/spreadsheets/d/1HusSV1qhMV3SI80JLWW6yLQJQ-A_PWh0YM0Xx7_BgmM/edit?usp=sharing

 

[TURBO2GO]

My simple answer for you is ra1 235/40/17 on a 7.5-8 inch front and 275/40/17 or 35/18 on 9.5-10 inch rear...I've been doing that for 12 years.

I have to agree, this is a simple solution and works NOW. Unless are unable to clear calipers or are buying new wheels and unsure about the future don't put yourself through this until all the dust has settled and there's a clear path to upgrade.

 

[Shaylord]

Dave and I are forced to do this, it isn't by choice we are the test subjects trust me. Dave has listened to me complain about this for months now, so everyone should go easier on him just for that. lol

 

[docjohn]

At some point you guys need to implement and tell us how your brave new world turns out. Until then All this discussion amounts to just psychotherapy. I'm still not sure exactly why you guys want a massive ceramic bbk .For Dave he should ask why many of the track guys buy there Porsche's and Ferrari's with steel brakes rather than the carbon or composite rotors.

 

[Shaylord]

These are a new generation of carbon ceramic rotors. Like Dave and I both have mentioned multiple times, we own these, it is not like we are now just deciding to buy these and now we have to go to the 18/19 wheel setup. They were supposed to fit under a 17" wheel but they don't, we own them. This is our only option, everyone else has choice, we do not.

 

[docjohn]

I understand that....after you kill the person responsible for the "will fit the 17 inch wheel" statement you guys now need to find a 18 inch wheel for the front of a car designed and engineered for a 15 inch wheel .....

 

[Shaylord]

nitto nt01s 235/40/17 are 620mm in diameter 225/40/18 are 637mm in diameter, 8.5 mm larger in radius, now I have been told that the nt01s almost are 30mm over on width. So yes they are larger in diameter, but where tires rub are on the outside edges in the cylinders if you will, the outside edge, corner of the sidewall and contact area of the tire. I believe the 225/40/18 and the 235/40/17 nitto which is over sized, the 225/140/18 might actually give more clearance as its the corners that hit.

- - - Updated - - -

its more the outside diameter and width I am concerned about. Does anyone have a CAD program where they could put both the tire dimensions in and rotate them and see where the corners travel compared to each other?

 

[docjohn]

I can't run a 235 nto1 too wide, the ra1 in the same size is narrower by 9 mm,and that is still fraying my plastic liner edge along the lip.

 

[TURBO2GO]

Does anyone have a CAD program where they could put both the tire dimensions in and rotate them and see where the corners travel compared to each other?

Yeah let me get that out my back pocket, I had been saving it for just such a purpose.

 

[Shaylord]

Wait are you serious or trolling. Ps in your signature you should note the Carbon Ceramic BBK is still in a box ;-)

 

[bngl3rt]

My simple answer for you is ra1 235/40/17 on a 7.5-8 inch front and 275/40/17 or 35/18 on 9.5-10 inch rear...I've been doing that for 12 years.

Fender liners on or off? OEM or wide fenders? A/c shroud on or off?

 

[docjohn]

fan shrouds off/liner on/ oem fenders.... wheels: ssr comps and enkei rpf1

 

[Shaylord]

I turned the spread sheet into 4 image files. Over all sizes and 3 comparisons to the 3 different factory sizes. Hope this is helpful!

 

[dablackgoku1234]

Can you make bigger image? The text is a bit blurry.

 

[Shaylord]

Sorry when I get home I'll get then fixed. That's how prime uploaded them.

 

[bngl3rt]

fan shrouds off/liner on/ oem fenders.... wheels: ssr comps and enkei rpf1

There a thread someplace on how to remove the a/c shrouds?

 

[TURBO2GO]

There a thread someplace on how to remove the a/c shrouds?

Just install a set of NT01 in 235 and you will quickly remove anything in the way.

 

[Caroline-NSX]

Just install a set of NT01 in 235 and you will quickly remove anything in the way.

Lol! Something gotta give...

 

[TURBO2GO]

These are photos I took of the rear yesterday. This is an 18x9 wheel at an ET of 25. I have well over 2" (closer to 2.25") of distance to the closest thing, the JRZ shock body. I had a concern with rubbing with the JRZ over a stock suspension. I can comfortably state that the JRZ or my old KW Competitions now on shaylors car provide MORE clearance over OEM than less. The stock shock/perch/spring is much wider than the tight Motorsport ones like these.

- - - Updated - - -

A couple of further notes.... This is with the car on ramps with a compressed suspension, not on jack stands. Also, a 19" wheel actually puts the wheel and tire lips further away from the shock than the current 18". A 20" would sit further still as the edge moves upward and further away from the angled shock body.

 

[stuntman]

Great contribution. You can fit wide wheels under the rear, unfortunately they have to have high offsets and most wide wheels tend to have lower offsets.

 

[TURBO2GO]

Great contribution. You can fit wide wheels under the rear, unfortunately they have to have high offsets and most wide wheels tend to have lower offsets.

Exactly. I am back to my custom wheel solution. There is just a ton more flexibility in terms of a particular offset and I won't need spacers or rings. Currently working with on a forged custom wheel that will give me the perfect offsets for caliper clearance, the most concave possible, and the exact et and hub bore I ask for. Not to mention design. It's more costly but the end result is a superior product.

 

[Envyscorpio]

Has anyone tried 225/35/18, 275/30/19 Yokohama S.drive from tirerack.com