Hey All! I'm planning on ordering my NISMO LMGT4's from performance nissan tomorrow and I was just wondering on the tire offsets that im thinking of would work well...

18" x 8.5" (Front), 18" x 9.5" (Rear)

and for the tires Michelin PS2... (I owned them with my Autocrossing vehicle last season and loved them)

F: 245/40/18
R: 265/35/18

Any suggestions?

I was looking for a R: 275/40/18 in the Michelin's but my local discount tire said they do not make the PS2's in that size...

either way... help me out please!!

 

245/40/18 have in outer diameter of 25.8" (stock 225/45/18 is 25.8")
275/40/18 have in outer diameter of 26.8" (stock 245/45/18 is 26.8")

Notice a pattern here? The stock electronics and handling dynamics are set up to handle this front to rear stagger.

265/35/18 is 25.3" in outer diameter. Therefore the rear tire will be .5" smaller in diameter than the front, rather than being 1" larger.

All the above dimensions are for the Michelin Pilot Sport. I think you can see it's the wrong thing to do. Not only will the handling suffer, but the gap between the tire and wheel opening will be .75" larger than it is now, and not look very attractive.

My advice - Find a different brand of tire available in the proper sizes.

BTW, the Nismo Wheel is a great choice. I love mine with my Dunlop SP9000s on them - In the proper sizes.

Lou

 

Hmm... I'd personally recommend a 255/40/18 and a 275/40/18 tire combo. When you do the math a 255/40/18 is the same diameter as the stock 225/45/18, and a 275/40/18 is the same diameter as the stock 245/45/18. Not only will this result in your diameters being almost identical to stock, but you'll retain the 20 mm width difference between front and back. This could help prevent making understeer worse than it already is.

The only drawback to using a 255/40/18 front tire is the limited choice of tires. It's a fairly rare size, so there's not much. I ended up going with the S-03 since it was the only good option. The S-03 is a very good tire, so I'm not unhappy, it's just that it's expensive. However, those PS2's are even more expensive, so I imagine you wouldn't mind going down in price a bit.

All this being said, there's nothing really wrong with a 245/40/18 and 275/40/18 combo. The 245 and 275 have a ton of tire options available, so you can have just about anything you want. Also, for what it's worth, Nismo recommends a 245/275 combo. (Although I'm convinced they did that just to increase understeer for the lawyers, as well as make your tire choice more plentiful.)

 

For what it's worth, here is a list of tire diameters I just worked up with a calculator. (I swear I should save this in a file somewhere since people ask it so much.) It's a bummer that the tire sizing spec is so stupid and complicated, and I think it's partially to blame for people getting weird tire sizes all the time. Remember:
The first number is tire width in millimeters.
The second number is sidewall height as a percentage of tire width.
The third number is the diameter of the rim in inches.

Various tire sizes rounded to the nearest 1/10th of an inch:

stock:
225/45/18 = 26.0"
245/45/18 = 26.7"

other:
245/40/18 = 25.7"
255/40/18 = 26.0"
265/35/18 = 25.3"
265/40/18 = 26.3"
275/40/18 = 26.7'

So, as you can see, a 255/275 combo gets you closest to stock diameters, and keeps you with the stock 20mm width difference. A 245/275 combo isn't too bad, either, but not as close as a 255/275 combo. A 265/35/18 would be a poor choice no matter what.

 

Goodyear F1 GS-D3 are available in 255/275 40 series also. That's my personal choice.

 

Doing the math does not usually work - exactly - when figuring the outside diameter of a tire. The dimensions I listed were taken from the Michelin Pilot Sport Spec. Sheet, and thus are true for THAT tire.

Examples: (245/40/18)

Michelin Pilot Sport - 25.8" as stated above (255/40/18 would be 25.9" - would be OK)
Dunlop SP9000 - 25.7" (255/40/18 - N/A)
Goodyear Eagle F1 - 25.7" (255/40/18 - NA)
Bridgestone SO3 - 25.6" (255/40/18 - 26.1")

So - As you can see there is variation depending on the maker.

Lou

 

Is it possible to have 265/40/18 in the front and 275/40/18 in the back?

 

Goodyear Eagle F1 GS-D3 255/40/18 = 26.0"

This tire is in production but for some reason most dealers don't list. Check Goodyear's site. If your dealer of choice does not list it, just ask, they can get it.

 

Yes. There are even folks who are running 275/40/18 all the way around. You just want to make sure have front rims wide enough to fit it. Check the manufacturer specifications for the tire you want and see what the acceptable rim width range is for that tire. It might vary a bit from tire to tire. As a test a while back, I mounted my rear Nismo rims on the front of my car, just to see if they'd fit. They did, and they look *incredible* on the front. There didn't appear to be any rubbing, but I'd probably put a 3-5mm spacer on there just to be absolutely sure it wouldn't rub the suspension upright, since it was extremely close. You'd also have to be careful about how low you drop your car with suspension, as you might rub the fender when turning the wheel sharply.

Another consideration is that you might run into a little bit of an issue with traction control, since it might get a little bit confused by the fact that there is no diameter difference between the front and back. However, I have yet to hear anyone with these sizes seriously complain about it. It's only minor stuff, like when you're pushing fairly hard around a freeway on ramp, traction control might kick in a little sooner than it otherwise would have. However, if you turn traction control off it won't be a problem. Since most people turn it off when they are out driving hard, I would guess this would be an okay compromise.

 

You are absolutely correct, but the math does work in general. Most actual tire sizes don't deviate very far from what the math comes out to, so it works out in the end. Either way, I still maintain that a 255/40/18 is (in general) a better fit and better performing option than a 245/40/18. (You'll get less understeer, and it looks better.)

 

Thanks all!!! All that info really got my straight on my info and let me know what I needed to do.... I see they do make a 275/40/18 and a 255/40/18 PS2 tires! ... I just think Discount tire might not have them for me to order! I did just check tirerack and they have them so im set! thanks again for all the help!!

 

I don't think Michelin makes the PS2 in the 275/40/18 size. I just got my LMGT4s put on about three weeks ago. I originally wanted the PS2s, but was told that they didn't come in that size for the rear, only 265/40/18s, by everyone I talked to, including the Tirerack and Discout Tire Direct. Unless that has changed in the last few weeks you can't get that size in the PS2s, but you can get that size in the regular Pilot Sports. I ended up going with the Goodyear F1 GS-D3s. I like them. Several other people on this board have them on their LMGT4s. The ride is better than the stock Bridgestones too.

 

yah your right... i was reading it wrong...

Man I REALLY loved those wheels... I'll have to research more... the grip of the PS2's were AMAZING!!! and I would LOVE to stick with them if I could...

 

You can also try the Bridgestone S-03 or the BFG KD. Many people say the KD is one of the stickiest street tires you can buy. (R compound not included.) In the KD you won't be able to get 255, but you can get 245.

 

Thanks for the input again Reiter! Does anyone know about the basic Mich PS's?? How did they stack against those Bridgestones or the Eagle1's ??

 

i'm getting 255 PS2 fronts and 285 KDW2 rear (since there's not PS2 in that size)

 

wow I never thought of that... doesnt have any side effects with the handling between two different treads does it?

 

Personally I wouldn't go with two different brands of tires front and rear. Also the KDWs I am told get louder as they wear due to the bigger blocks in the tread. I have heard good things about the S03s though.

As for your question about the Pilot Sports vs the PS2s, the Tirerack has a good survey of the different performance tires available. I was just like you and wanted the PS2s. However, the regular Pilot Sports did not fair that well on the survey, but the Goodyear GS-D3s and S03s did. I talked to several people on the forum who had the Goodyears and really liked them with the Nismo wheels so I went with them over the Michelin Pilot Sports. Again if I could have gotten the PS-2s in the correct size I would have purchased them instead. I just wanted to stay with the recommended tire sizes.

 

Sentry

You really don't want to mix different brands of performance tires. Might bo OK on a Civic with M&Ss. On a performance car with performance tires you want to stay with the same brand and model. Handling characteristics differ from brand to brand, and those differences will be exacerbated if the tires are mized. Look at the differences in tread design, and you'll see how different they are.

Lou

 

yeah i dunno, the nismo wheels are the only wheels I really like, but if i end up being stuck getting 245 and 275 on them, it starts making them feel not worth the effort as much. I really like the PS2's

So I'll have to decide if I want KDW2 255 and 285 for $790 or
PS2 245 and 275 for $1046

as far as KDW2 noise, unless it's ridiculously loud/annoying, chances are it won't bother me - my car already makes enough noises/loudness to negate it. Also according to tirerack, they're much better with noise and comfort than the stock tires. It's nice that they're $256 cheaper than the PS2's - that's 1/3 less than the PS2's. I've heard the S03's get really noisy towards as they wear too. And that they're heavier tires. Overall they don't rate as well as the KDW2's according to tirerack. The Goodyear GS-D3 seem like really nice overall tires, hmm. But they don't come in 285/40 and 255/40 Still kinda leaning toward the KDW2's at this point...

also, with the 245 and 275 setup, you get more understeer than you would with a 255 and 285 setup, but then again, the 245 and 275 setup probably has more nimble feel. Overall I think there'd be more grip with the 255 and 285 KDW2's than 245 and 275 PS2's

I can put 245 and 265 on my track wheels as is. I know the nismo wheels would be a better choice for keeping the tire buldge down, but agh. If only nismo would make their 10.5 18in wheel in something other than a 15 offset.

Maybe I should just get a wide body kit or something