My over all is off by about 3/16 of an inch so yes you can get very close, my spedo is off a whopping 2% or when I'm going 70 my speedo reads 69, hell they can be off that much from the factory.

 

Well sure at that size there is but if you are trying to match stock tire size over all with 20's it's no problem.

 

You're so wrong its not even funny. STOCK 18 tires are 235/50-18 which is an overall diameter of 27.3"

Ouch.

 

You mite want to try READING my post first. Was I talking about stock tires? NO. If you want to play with the big boys try acting like one. My numbers are correct don't beleave me check them yourself. Some peoples kids gee...........

Here I'll post the math for you. 255 x .35 = 89.25mm x2 =178.5mm Then convert the wheel to mm 18 x 25.4 = 457.2 then add them together 635.7mm then convert it over = 25.02"

 

No where in you first post did you say you weren't talking about stock tires.

Of course an 18" wheel can take an overall smaller tire. You're just using whatever gay tactic you can to debate with. If that what it takes to prove your point, so be it.

My point is that I don't want the OP to be confused thinking you can't buy 20"s that will retain the stock overall size. Too many people have posted that 20"s will make the stang sit higher. That is 100% false.

 

My 20 tires are 0.10" larger than stock my 17" tires and exact same as stock 18" tires. I highly doubt Ford calibrated mustangs differently depending on whether than had 17's or 18's.

 

Nice, now you have to try to further insult me after seeing that I was indeed correct in my statement. Gay Tactic? Since when did using common since and math become gay?

 

Its gay because no one is going to get a tire that is over 2" SMALLER than stock.

And I repeat. NO WHERE IN YOUR FIRST POST DID YOU SAY YOU WERE TALKING ABOUT RUNNING A NON STOCK DIAMETER TIRE.

 

Oh I agree fully with you about the point you make with the 20's. The "tire" size plays a huge roll on how it sits. My first statement was in general terms when you combine 18's and lowering springs your car will have an apearance of being very low to the ground and will (most of the time) physically sit lower than a car with 20's. I hope that clears that up and I'm sorry if I was not more clear in my first statement.

This is what I was trying to get at. My girlfreind has an 07 Roush with 275x40 18's and she has the same amount of drop spring wise as I do. I'm running 265x35 20's which puts me just about 1" taller than hers. Now when we go over the speed bump where we live she scrapes across it where I do not. So even thow both cars look the same hight wise hers sits lower.

No hard feels man we were both trying to get to the same point but we were looking at it from diffrant view points

Also, when your talking about 18's vs 20's in general you have to take stock out of it since Mustangs do not come with 20's stock. Again, diffrant thinking same point

 

Understood. Sorry about the name calling, I don't like being called kid, lol. That's cool you both got stangs, lovely. My GF has a Focus.

As for the OP, they just need to know 20's fit without a problem. They can be ran with the same springs and drop you would run your stock tires with.