I needed to get some new tires and I had seen that the front tires were 225/45, but the guy at the tire place said that the fronts could also take 245/40's on the 18" wheels.

Was he right, or am I going to be pissed when I go in to get the tires put on and they won't work?

 

They will fit just fine, and maintain the stagger (the outer diameter of both sizes are very similar). The 245/40s will lessen the understeer that is built in to the "G" with the narrower 225/45. The car will be more neutral handling. You may or may not like this. The 225/45/18 size is rather hard to find. 245/40s are far more common. IMO, you ought to try it, you probably will like the change.

However, what about the rears? In a performance car, like ours, it's wise to keep the brands (read tread pattern) the same front to back. With the 245/40s in front the stock size 245/45 or 255/45 will work in the back.

Lou

 

If you stay with the Michelen Pilot Sports, the tires should fit. Following is a link to the Pilot Sports' page. The spec sheet will indicate the rim width that is ok for the tires.
http://www.michelinman.com/catalog/t...etype=3&tire=2

 

I just mounted 245/45 ZR 18 all the way around and am more than pleased with the result. Another member suggested that I try 245/40 ZR 18 next time.

My recollection from the last time I saw tire size/speedometer specs was that at 60 mph, the 45's were less than 1 mph off and the 40's were about 3 mph, but check to be sure.

 

Sorry, but wrong. You just killed the stagger. VDC should kick in quite a bit in spirited driving. As far as the differences in Outer diameter with the sizes we are speaking of - For Pilot Sports:

225/45/18 = 25.8"
245/40/18 = 25.8"
245/45/18 = 26.8"
255/45/18 = 26.9"
Some other tire brands may vary by not more than a tenth or so.

But as you can see Nissan (Infiniti) built our cars with a 1/2" height stagger (front to back), and tweaked our electronics to match. You have upset this, and you could run into problems.

You can see from the figures above that 225/45 and 245/40 are the same height, and thus would have no effect on any speedometer readings.

Lou

 

Yes the OEM stagger may be off, but it's not hurting anything really. For the winter I run 235x45x18 on all corners. No problem and is much better than the understeer from the stock widths.

Due to my eibachs, I am ordering 245x40x18 for the front. The oem's are howling like a road repair crew.



"Planet Is Full, Go Home." - Hooter's Sign
G35 Coupe 5AT, DP, Tire and Wheel Pkg., Aluminum Pedals, Clear Corners, missing turbo

 

Yea, I am changing the backs out as well to some new 245/45s.

I'll let everyone know how they go.

Thanks everyone!

 

Anyone try a:
235/40/18 & 255/45/18 combo?
I got that VDC ABS thing too.
I tried to emmulate it again but it hasnt appeared again.
I shouldve gone with a 245/40/18 front...

 

sorry i'm a newbie and don't know jack about tires...but from what i'm reading 255/45/18 is fine for the rear, right?

I have new mich. sports 225/45/18's in the front...will the 255/45 be ok for the rear?

 

From all other posts, a lot of people suggested 255/45/18 for the rear; So I dont see a problem with that size. My Stagger seems too extreme being the stock front tire diameter is 26.0" to 25.4" and the rear 26.7" to 27.0". Difference: .7" to 1.6" stagger. So far the VDC/ABS Fault hasnt appeared...just once. I've read that it should re-appear with "spirited" driving...and I do a lot of "spirited" driving...breaking the rear loose, going sideways in parts I can get away with and it hasnt reappeared...yet.

 

PUH-LEASE.....
there are many people who have never seen or tried any other wheel combo than what they read about. Then they spout it out as if it was the WORD.
yes tire manafactures have recommended guidelines, which are very very conservative. They do this for legal reasons for the most part. Try going to an auto cross event or road course event & check out the tire/rim combos that the people who are actually racing, are using. Most of them will not even bother posting here about tires & rims because there are so many people who know "nothing of what they speak" just waiting to flame them. I on the other hand want to let ya'll know about my experiences with my stock 17in rims.(8in wide)
I have 255's on the front & 275's on the rear. Fit fine, ride great, no bulge. PERIOD.

2 year's auto-crossing (15+ events)
1 HSDE course 125MPH+

255's will work fine on the rear, I had Pilot sports on the rear for 1year before I changes to my current setup.
note pics...
85MPH+ turning onto the front stretch
90MPH+ through the esses
125MPH+ on the front

 

sorry if I ranted, but I just work 7 night shifts in a row & now I'm off for 7!!

Good luck in your choices

 

245/40 all around on 8" rims.

 

I am running Ealge F1 GSD-3 245/40/18 in the front and 245/45/18 in the rear. No vdc problems yet, but the handling slightly improved.