Yeah, getting the proper offsets so you can run that much tire would be a good plan, and the 245/285 stagger looks

 

Haha yeah, I love the look of meaty tires. I'm only asking about these offsets cause they are being offered at a really good deal.

 

Hey, when measuring the variance...how do you properly calculate the numbers between front and back seeing as they are different sizes? Do you take whatever number for both and divide by 2 to get the average? Just curious of the best way to do it...the most accurate

 

I'll get back to you tonight, stay tuned

 

Use this calculator
https://www.myg37.com/forums/tire_rim_calculator.php
Plug in the front tire on top and the rear tire on the bottom. If you have a negative % the tire on the bottom is smaller, if the % is positive the top tire is smaller diameter.

Ideally you want a slightly larger diameter in back since the rears wear faster, this will bring the variance closer to zero over time. If you start w/ a smaller diameter in back the variance will get worse over time.

And once you get tires w/ a good variance you can go to the tire brands' website and look up the exact diameter for that tire model & size, then just divide one diameter by the other to get the true variance of that brand tire at those sizes.

FWIW here's a list of some of the more common sizes in combos that will work w/ AWD staggered setups~
18s
235/45 & 265/40 (0.07%)
245/45 & 275/40 -0.07%
255/45 & 285/40 -0.22%

19s
235/40 & 265/35 -0.37%
235/40 & 275/35 0.67%
245/40 & 275/35 -0.52%
245/40 & 28535 0.51%

20s
235/35 & 275/30 0.07%
245/35 & 285/30 -0.07%

 

This method wont work for a square setups. Well i'll have to right down the differences and then do the math.

So for mine the fronts end up .06" (.22%) and the rear is .31" (1.17%)
So if I divide the rear by the front it ends up being 5.32%. Is that right? That seems awfully high and problematic apparently.

 

Not really sure what you're wanting. If it's a square setup you just use your OEM tire size on the top line and your new tire size on the bottom. With AWD you want front to back to be under 1%, if you just want to run a different square setup then you can be up to 3% difference.
What tire size are you wanting to run?

 

I'm also confused. If you run a square setup, that means front & rear tire size will be the same so there's zero difference.

 

^^^Exactly. I will be running 255/40 19 square. If I do the math according to the calculator, both wheels, compared to stock size, are close as you see from my previous post. But when you do the average as you said the overall % difference is like 5%. That seems high.

 

On a RWD S coupe the speed sensor is set up for a 245/40/19 tire, so going to a 255/40 will result in a 1.17% larger diameter which is just fine for a square setup. If your coupe is a base w/ 225/50/18s they would be only 0.64% larger.

 

ok goo. So the rear is all I really needed to worry about! Thats all I needed to know

 

Thanks I'll see what input they'll have for me

 

Help! I have a 2013 G37x Sedan. After reading up on wheels for quite awhile and after talking with Discount Tire I purchased a set of Konig Oversteers in 19x8.5 +30 square with 255/40/19. I liked the meatier/wide tire for a little extra curb protection. Unfortunately at stock height I have almost 10mm of poke outside the fenders. My question is #1, can this size/setup work on sedans (under compression will this hit my fenders) and #2 could it be fixed if I dropped it about an inch or run some negative camber? How much would a mild drop effect the poke i have? What are my other options for making these wheels work ie. springs, camber adjustment, etc? Thanks in advance. blnewt take the wheel!

 

That's easy Mike, those will tuck just fine under compression. The look right now is a bit poked but nothing crazy. A milder Eibach or Swift drop will have you looking proper, and even as it sits (with the exception of the tire/fender gap) it's not bad at all.
IIRC the tires will tuck about 1/3" for every 1" drop, so a 1.25" drop will get you just about the 10mm you're extending from the fenders.

 

Been researching seen 20x10.5 et 38 or so is pretty common but I am bagged so when I air out I gain a lot of camber wondering if anyone has done 20x10.5 +10 square on a sedan looking for lip to fender fitment