Sorry if the question has been answered, folks, but I was curious as to the largest tire one can fit on the FRONT of a 4th gen. I have found 285 40 18's...BRAND SPANKING NEW Goodyear Eagle F1 Supercars for $99 each! I was going to get them all the way around.

 

A member here has 275s on the front of his 94.

 

Yes and thank you. I know those will fit, but I'm wondering if the extra 10mm will cause rub. 285's on the front is pretty damn beefy, but finding those tires...at that price...is absolutely freaking insane! The place selling them is about 35 miles from me, but I'd still likely have them shipped. If you know anything about L.A. traffic, it's almost worth paying the extra $50 to avoid the hassle! I'll probably just call the place on Wednesday.

 

275 came standard on ws6 and SS cars on all 4 corners.

285 is the widest you can fit on the front with a 17 inch rim and 40 aspect ratio. On an 18 inch rim with the same 40 aspect ratio you will more than likely have clearance issues. The height difference between a 275/40/17 and a 285/40/18 is close to 2 inches.

 

Nooooo! Ugh...looks like I won't be able to get those F1 Supercars for the front. Sad, too. For some strange reason, only the 285's are on sale. How about a 285 30 18...acceptable?

 

Failed is giving you good info but it's math time as it seems that nobody has explained this to you yet.

Anyway, first and foremost the 18's are no good to you if you have 17 inch rims; you understand that don't you?

now to the math

I'm going to use metric

25.4mm is 1 inch

17 inches = 432 mm (rounded)
18 inches = 457 mm (rounded)
let's discuss aspect ratio and use a 17 inch tire for this exercise

what we are looking to discover is tire diameter or tire height

naturally the 17 inches (432mm) is part of it because there is also the tire in the equation

a 275 40 17 tire is

275mm wide
the 40 is what is known as the aspect ratio. That is, 40% of the width is the height of the sidewall.

So, if you have a new 275 x 40 tire (diameter isn't important yet) then the sidewall height would measure 110mm. To get the entire height of the tire you need the diameter plus 2 times the sidewall. Or, if it's a 40 series (aspect ratio) just multiply the width time .8 which is 40 twice and you get 220mm

so, the tire height of a 275 40 17 tire is the 432 mm diameter plus 2 times the aspect ratio or 220mm so 432 + 220= 652 mm tire height (24.9 inches)

now what happens when we add an 18 inch diameter but keep the same width and aspect ratio is that you added an inch to the tire height.

So, to hit the tire height of around 25 inches and to use an 18 then you need to either reduce the width and keep a 40 aspect ratio or keep the 275 and reduce the aspect ratio (35 or 30 but the math will get you there)

with the 285's and going to an 18 and a 40 aspect ratio then the tire is even taller than a 275 40 18

Now, if your headlights perhaps are aimed too low, there are much easier ways to get them aimed upward than to increase the ride height in the front.

I hope this exercise helps you better understand what those numbers mean when you tire shop.

 

Thanks for the math lesson, LOL. I will do my best to figure it out from there.

As it stands, I currently have 18" rims and the front is actually lowered 1.5 inches. The rear will be lowered 1.2" in the very near future. I've found a few different options for tires, including 285/40/18 rear and 245/40/18 front, Eagle F1 Supercar since my last post. Total price of $550 + shipping. I've also found other options, most notably some Z rated Generals for about $500, free shipping. 285/35/18's.

I know the 245's will fit up front and the 285's will fit in back-even lowered-as I had them before. I was just thinking about going bigger if I could because $99 a tire for brand new F1 Supercars is pretty damn awesome.

 

Well, a little searching online found me this handy tool:

Tire Size Calculator - Compare Tire Sizes