Front wheel setup + tire size recommendation

[sliqq]

Hi guys,

I've got a couple sizes to choose from for my front setup

17x7.5 +45
or
17x8.5 +54

I will be running 18x9.5 +45 in the rears.

Also what tire size do you recommend. My car is a 1992 with stock brakes. I'm looking to get a good compromise between performance and looks (None to very little tire stretch and a flush look without rubbing).

 

[TURBO2GO]

Seems like everyone asks the same questions without reading other threads.

8.5 is too wide for the front. 215/40/17 front, 275/35/18 rear. 265/35/18 rear, 255/40/17 rear will all work. Depends on what tire you choose and what is available.

 

[Darknightnsx]

Would a 18x8 with 45+ offset work on the fronts? thanks.

 

[myw]

^^ should be safe. Depending on the wheel/spoke style u may need a spacer

 

[nsxtasy]

The best 17"/18" sizes for a '92 NSX are 215/40-17 in the front, and 265/35-18 in the rear. (I would not recommend 275 in the rear, as the handling degrades when the "stagger" - difference in tread width, front vs rear - is as high as 60 mm.)

Get the 17x7.5 front wheels. 18x9.5 in the rear is fine.

 

[sliqq]

Thanks for the help guys.

Picked up the 7.5s for the front and will be using the tires from my old rims until they wear out. Will keep the tire size suggestions in mind for my next set.

 

[jaffaz32]

Tire choices are very limited on a 215/40/17

Can you change the width or the profile slightly at all to give more choices of tire?

 

[TURBO2GO]

Tire choices for the front are limited period. You can go 235/40/17 but you'll rub on full lock. You can go wider wheels and tires but you will need wider fenders like the downforce. There are some really good tires at 215/40/17, what are you looking for? Michelin doesn't care about us... LOL... But Dunlop, Yokohama, continental, falken and kumho do.

 

[scammy]

I'm considering a new set of rims and that is the size i am looking at is their any particular offset thats is best in your opinion or range of offsets for front and rear, i havent decided on which rims i am getting but looking at putting NT01s on the new rims for track days

The best 17"/18" sizes for a '92 NSX are 215/40-17 in the front, and 265/35-18 in the rear. (I would not recommend 275 in the rear, as the handling degrades when the "stagger" - difference in tread width, front vs rear - is as high as 60 mm.)

Get the 17x7.5 front wheels. 18x9.5 in the rear is fine.

 

[nsxtasy]

Tire choices are very limited on a 215/40/17

Can you change the width or the profile slightly at all to give more choices of tire?

No. But there are some very good tire choices in 215/40-17 (and in 18" rear sizes).

If you want the very best grip for street use and even an occasional track day, you will want to get one of the "extreme performance" tires. Those available in 215/40-17 include the Dunlop Direzza Sport Z1 Star Spec, Yokohama Advan Neova AD08, and Falken Azenis RT-615K.

If you are willing to sacrifice a bit of performance for longer treadlife, the Kumho Ecsta LE Sport (a "maximum performance" tire) is available in these sizes.

I'm considering a new set of rims and that is the size i am looking at is their any particular offset thats is best in your opinion or range of offsets for front and rear, i havent decided on which rims i am getting but looking at putting NT01s on the new rims for track days

Decide on your tire sizes first, then on your rim width, and only then on your offset. For example, with the NT-01, if you want to go with the oversized 235/40-17 (assuming you don't mind rubbing since it's for track use), it's approved for rim widths of 8.0-9.5", so you'll probably want 17x8.5 or 17x9. But if you want to go with the 205/40-17 (maybe because you'll occasionally use it on the street and you don't want rubbing), that's approved for 7.0-8.0" widths, so you'll probably want to go with 17x7.5. Once you decide on a width, you'll have to ask around to see what offset works best for that rim width.

 

[Ric]

Are these extreme performance tires safe to drive in the rain?

 

[Hapa88]

Are these extreme performance tires safe to drive in the rain?

How much rain are you talking about? If you live in San Diego, CA, then rain shouldn't be an issue.

 

[Ric]

The normal socal rain. I don't purposely drive my nsx in the rain but once in a while I get caught in the rain. There are quite a few primers here who crashed their nsx in the rain, so I am extremely careful when it's raining. I remember reading some nsx mag review and it said the nsx is tricky to drive in the rain.

 

[chussey]

The normal socal rain. I don't purposely drive my nsx in the rain but once in a while I get caught in the rain. There are quite a few primers here who crashed their nsx in the rain, so I am extremely careful when it's raining. I remember reading some nsx mag review and it said the nsx is tricky to drive in the rain.

I was pleasantly surprised at how well my Direzza Star Spec's perform during heavy rain (and we get plenty of it in New England).The soft compound works great on wet roads if there is no standing water. As long as you have sufficient tread depth remaining, hydroplaning should not be too much of an issue. Of course tread depth was nil on my rears by 5kmi.

 

[TURBO2GO]

The normal socal rain. I don't purposely drive my nsx in the rain but once in a while I get caught in the rain. There are quite a few primers here who crashed their nsx in the rain, so I am extremely careful when it's raining. I remember reading some nsx mag review and it said the nsx is tricky to drive in the rain.

The NSX isn't tricky in the wet as long as it is setup right, but just like with any high perfromance car its tolerance for going over its limits is low. The NSX, with its suspension design and rather narrow tires is better than other sports cars who use even wider tires and have less compliant suspensions.

One really important thing is the alignment of the NSX. If the alignment is off, all your worst fears in the rain may in fact come true. If it is right, the car is very stable even in the rain. I can't stress this enough. I have felt this first hand in wet conditions. A misaligned car will not behave well.

 

[9doors]

No. But there are some very good tire choices in 215/40-17 (and in 18" rear sizes).

If you want the very best grip for street use and even an occasional track day, you will want to get one of the "extreme performance" tires. Those available in 215/40-17 include the Dunlop Direzza Sport Z1 Star Spec, Yokohama Advan Neova AD08, and Falken Azenis RT-615K.

If you are willing to sacrifice a bit of performance for longer treadlife, the Kumho Ecsta LE Sport (a "maximum performance" tire) is available in these sizes.


Decide on your tire sizes first, then on your rim width, and only then on your offset. For example, with the NT-01, if you want to go with the oversized 235/40-17 (assuming you don't mind rubbing since it's for track use), it's approved for rim widths of 8.0-9.5", so you'll probably want 17x8.5 or 17x9. But if you want to go with the 205/40-17 (maybe because you'll occasionally use it on the street and you don't want rubbing), that's approved for 7.0-8.0" widths, so you'll probably want to go with 17x7.5. Once you decide on a width, you'll have to ask around to see what offset works best for that rim width.

Ken, speaking of NT-01's...if you go with a 205/40/17, what's the right size for an 18" rear?

 

[TURBO2GO]

Ken, speaking of NT-01's...if you go with a 205/40/17, what's the right size for an 18" rear?

If you go to tirerack.com and look at a tire, you can click specs and get all the info. Look up stock sizes and if you increase front by 3mm, try to increase rear by 3mm. If you do the same front and rear, the TCS is happy. A 205 is 10mm narrower than a 215 in section width. It's a 40, so your sidewalls are 40% of your tread width. 40% of 10 is 4. You have two sidewalls in overall diameter so you double the number which is 8. So a 205-40 is 8mm shorter than a 215-40.

What the best rear 18" match is, depends on the year of your car.

 

[9doors]

Thank you for the math! I always find the discussions like this and relationships between F/R/TCS mentioned, but not laid out as you have done here. In my specific case I have an 01.

 

[TURBO2GO]

Click specs on this page.

Your front diameter stock is 23.1 and rear is 24.9

Nitto NT01 205/40/17 front is 23.5.

You've increased front by .4 inches.

If you increase the rear by 0.4 as well, you will need to be at 25.3

The closest is Nitto NT01 is actually 235/40/18 at 25.3

If you go wider, both the 245/40/18 and the next size up at 275/35/18 are 25.5. I think both of these are acceptable and within range as well... but a 275 is MUCH wider than a 205 front, and a 235 is a bit too narrow IMO, so your best bet in an NT01 is 245/40/18.

If you went with the 235/40/17 front, then the 275/35/18 would be your best bet but you will rub on full lock.

All the NT01 specs are here:

http://www.nittotire.com/Tire/nt01#size

Like I said, figure out your stock diameters first, see what you've made for a change in front (increase or decrease), make the calculations to apply the same in crease or decrease to the rear, and look up the specs and see which tire is the closest in overall diameter. That's the process.

 

[9doors]

Perfect. Thanks so much.

 

[nsxtasy]

Your front diameter stock is 23.1 and rear is 24.9

Wrong. For one thing, the Star Spec isn't available in his front size, so you can't determine it from the Star Spec specs. In any case, you're better off using one of the "tire size calculators" you can find on the web (like this one). Or you can create your own spreadsheet for these calculations.

You've increased front by .4 inches.

Nope. The stock 215/45-16 tire size for the '94-01 NSX has a calculated outer diameter of 23.62". The 205/40-17 size is 23.46", or 0.7 percent smaller than stock.

235/40-18 is 2.8 percent larger than the calculated 24.72" diameter of the stock rear 245/40-17. With the resulting difference in the stock front-to-rear ratio of 3.5 percent (one is 0.7 percent smaller, the other 2.8 percent larger), you're on the borderline of having TCS problems. You would be better off with the smaller 225/40-18, which is 1.5 percent larger than stock, thereby changing the ratio by 2.2 percent.

These really aren't great sizes for the NSX, though. Not for track use (and you would only want to use these track tires for the racetrack). OTOH you don't have to worry about the TCS if you're only using them for the track.

If you go wider, both the 245/40/18 and the next size up at 275/35/18 are 25.5. I think both of these are acceptable and within range as well...

Definitely NOT. With a front size that's 0.7 percent smaller, using a rear size that's 4.1 percent larger (245/40-18) will definitely cause TCS problems, and one that's 3.5 percent larger (275/35-18) is likely to have TCS problems too.

 

[TURBO2GO]

9 doors, I thought you said your car was a 91. So although it being a 2001 (which I just noticed) throw my measurements off, the concept is the same. Anytime you want you can look up the specs and do the calculations. What I posted applies to a 91-94 NSX. I'm glad Ken caught that. Sorry bud...

23.46 is the 205/40/17 diameter, 23.6 is your stock. You are only .14 or so off depending on tire brand, tread depth, etc. It is negligible.

So your rear, stock, is 24.7... there is nothing in an 18" NT01 that is that close.

Are you running this strictly for the track? why do you want to go with a 205 front? Are you having clearance issues? You can switch to a 215 or a 235 and match the rear with a more appropriate tire.

 

[nsxtasy]

9 doors, I thought you said your car was a 91. So although it being a 2001 (which I just noticed) throw my measurements off, the concept is the same. Anytime you want you can look up the specs and do the calculations. What I posted applies to a 91-94 NSX. I'm glad Ken caught that. Sorry bud...

No problem.

The biggest difference in wheel diameters among NSX years is that the outer diameter of the '91-93 front wheels was significantly smaller (2-3 percent) than the '94-05 sizes. The '94-05 rear sizes were both within 1 percent of the '91-93 rear. So a '91-93 needs a bigger difference, front vs rear, for the proper TCS operation, than a '94-05 does.

Oh, and it's all approximate. Theoretically TCS has a problem when the difference is more than 5 percent from stock, but in practice, tires come in sizes slightly different from what they're labeled (sometimes this is reflected in manufacturers' specs, other times not), and you have other variables too. The difference in diameter due to a tire that's worn and needing replacement, vs one that's brand new, is around 2 percent, so that difference gets added in too.

 

[9doors]

No worries guys. Ken, thanks as always for dialing in the data. Dave, thanks for being so helpful.

Oh, and to answer your question. Yes, this is a track-related query. I'm currently running Kumho XS on the OEM 16/17 setup. I'd really like to go to Nittos as well as a 17/18 setup. I have the KW V3s (not your out-of-this-world Competitions) and the car is lowered. I know the 235 will work up front, I'm just worried about what will happen on compression. I know you can go with a 205/245 setup on the 16/17 OEM wheels, but didn't know (and oh, have I searched) to see if the similar idea would work on a 17/18 setup. I'm not worried about TCS on the track, since its off, but i do have to get to and from the track and don't have the benefit of Ken's 91 for tire transport. My other longer term option once a trailer enters the picture, might just be to stay with Kumho and run the V710s, but that is many track days off...

 

[TURBO2GO]

I don't think rubbing on compression is an issue, it's turning full lock that makes it rub slightly and it's on the inside. Something that never happens on the track.