Is anyone running 245/40R18 front 265/40R18 rear on stock 18x8 wheels? 350Z tech says it works, but they did not say what year car or width rim. If so what do you think (rubbing, tire pressure ect)? I have stock tire sizes now and need new tires, I would like to change sizes. Sorry if these is an old question I have search and many tire Threads are for none stock wheels. Thank you for any help.

 

265 is quite wide for an 8 inch rim. 245 IMO is pushing it.

fat tires and skinny rims belong on muscle cars.

 

245 is the widest recommended tire for an 8" wheel. The stock tires for Coupe 18's are 225/45 F, 245/45 R. You could possibly squeeze a 255 on there (I'm considering it), but a 265 is just too wide. You'll really be stressing the sidewall which will want to roll a little more in the corners since the tread is floating over a narrower base. You'll probably also have wear issues down the road (extra wear down the middle and possible cupping). A tire place will definitely try to talk you out of it and may not honor any warranty issues knowing what it was mounted on. Can you mount the tire? Sure. Should you? Probably not. A 9" wheel would be better for a 265. If you want the wide rear tire look, get some Coupe 19's and you can run a 265 or 275 tire back there.

 

I was thinking 265 was alittle big, but when I saw 350Ztech I started thinking about it. I am most liklely go with 255. I have been all over the tire sites, it good to hear from a real person, thanks for the replys.

 

How do feel about the front at 245/40R18 rear at 255/40R18. It looks good on 1010 Tires. On Tirerack with the tire I was looking at Sumitomo HTR Z III, they say for a 255/40R18 the max rim width is 8.5in. I know people go beyond what the charts say but... A friend of mine runs much fatter tires on his 04 STi, hes done it for years, no trouble. Any thoughts, thanks.

 

I assume you mean min. I've seen a few other sites that show a 255 width will fit on a 7.5", but that doesn't seem right. I've heard and read that the width of a tire, in this case just over 10", should never be more than 2" wider than the wheel it's going on, in this case 8". But it's really close, and there are definitely people that have done it without any problems. In a few other posts on here I've said not to do it, but I've learned alot since then and have changed my mind.

As for the setup you're looking at, it should work fine. I have Coupe 18's but I have a Sedan. They look great on the car and are nearly flush with the sides, but that's with the OEM Coupe tire sizes, 225/45 F, 245/45 R. I need to look again, but I'm almost certain that a 245/45 in the front for me will push the tire outside the wheel well, but should be fine for you with a Coupe. I also have AWD, so I need my tires to be the same diameter. I'm thinking of a 225/45-18 F and 255/40-18 R setup. Tires are almost identical diameters and will be very flush with the side of the car. I'm thinking of buying a really crappy used set of 255/40's off ebay just to see how they fit/look before I buy better tires.

If you have the stock Coupe sizes right now, swap one of your rear tires to the front to see what it looks like. It won't be identical to the 245/40 (taller sidewall), but the width will be the same and that's your concern.

 

I do have stock sizes 225/45R18 245/45R18 as you said. Thanks for your post, there is so much info out there it is hard to go thourgh it all. I would love to get the tires closer to the sides of the car, it just dont look right stock. I have thought about spacers but I dont know, sounds like trouble. I will have to try moving a rear to the front to check it out. I am still about a month away from getting tires, and new wheels are out of the question. If I go with a 255/40R18 over the 265 I will save $18 (that pays for one to be mounted lol). Thanks again.

 

Spacers are the way to go if you want to push the wheels out a little, but do some research on what size to get. And wait until you have the new tires installed before deciding on spacers. At that point put your car on a very flat and level surface and put a 4 foot level next to your wheel well and measure the distance from the top outside edge of the tire to the edge of the well. That will give you a starting point for knowing how big a spacer to get. Also search here for info.

And don't get the 265's. The 255 is already cutting it pretty close.

 

I have looked at spacers in the past. It was to long ago to remember the sizes, but I had done the research. Oh and I did mean MIN wheel width. They do make a Sumitomo HTR Z III in 255/40R18. My buddy's dad has them on his SL500 and loves them. Hes company makes ECU's for race teams, if he likes them there probably ok. How do you like your 5/16th spacer? That will be my next Mod.

 

Love the spacer. The car really jumps after about 3K RPMs all the way to redline. The spacer and Z-Tube are really a must-have upgrade for this car. It should be the first thing everyone does.

I would look at lots of tires. The Sumitomo's are good, but there are better tires out there. Bridgestone Potenza RE760 Sports and Nitto Invo are both available in the sizes you want.

 

I have a couple of real world experiences with my 04 G35 Coupe 6 speed w/Bremebos. First, the stock 18" rims are factory fitted w/225mm wide, 45 series on front and 245 mm wide 45 series tires on the rear. My upgrade upon tire replacement was 235mm wide, 40 series on front and 255mm wide 40 series tires on the rear. This works very well and basically are the widest tires you should fit given the factory rim widths. Anything wider and as another posted reply suggested, you are creating a situation of tire sidewall flex that negates properly handling. I just put new 19" TSW Chrome Indy 500 wheels fitted with 245mm wide 35 series on the front and 275mm wide 30 series tires on the rear. These work very well but remember that the wider the tires are, the greater the chances of hydro planing in heavy rain. Also, I have noticed an appreciable increase in resistance to plowing through heavy standing rain on the highway with the wider front tires. In the dry the 19" combination is great. Many owners have gone to 20" tire/wheel combinations and even wider tires. The reason to go beyond the factory tire diameter sizes is all about cosmetics, not increasing handling or cornering speeds. Research into tire diameter sizes used in serious auto crossing or track usage will show that 18" diameter is usually as large as these racers go, increasing tire width is the key to better handling, not tire diameter size.

 

Wow, those fronts are pretty small. I don't mean width, I mean diameter. The 235/40 is about 2.2% smaller than the stock 225/45's, which already looks too small. I'd never go that small. I guess you can call it an upgrade, but I wouldn't.