I have been researching buying some 18" wheels for my 07 Mustang. I know that the wheel offset is +45.

Why is it that several wheels companys show rims with +25 or +35 when doing a search for 05-06 GTs?

Is it that big of a problem to go with wheels with a smaller positive offset. I read here that some might need spacers.

Any thoughts would be appreciated.

B2

 

You need to educate yourself on offset and its significance. Look at the tire racks education site. A POSITIVE offset really should be decreased at least as much as 12.5mm for every inch increase in wheel width to avoid any backspace issues. So a 10 inch wide rim for our cars should have an offset of 45-25=20mm or less to avoid rubbing on the backside. My wheels are 18x9 so the offset needs to be 45-12.5=32.5 or LESS.
Their 24mm offset actually pushes the wheel out 21mm more than stock. (12.5(1/2 of one inch(for the additional inch in width))+8.5(the additional offset below 32.5). Hope you get this. It can be confusing.
!

 

Thanks for the info. I will try to get a better grasp on this. So this only applies if I am going up in tire size from the OEM 17x8 that come with the car. If I went with same size I would need to stick with the +45 offset. Thanks.

B2

 

The only problem there is that the S197 has plenty of spare backspace left to play with, so there is no need to move the offset significantly until you reach the 10" width. Most 10" rims for this car are built on a 45mm offset.

A lot of places are still listing pre-05 wheel fitments for the current generation Mustang, which is where the 25-35mm offsets are coming from. This is why I encourage people to actually do the math themselves instead of just searching for Mustang wheels and assuming that's what will fit, and that's all that will fit.

As I've stated before, you can base your fitment on the MustangTuning 18x10 +45 wheels. These are pretty much the maximum that will fit comfortably on all four corners. The rear seems to take a 10.5 wide +50 wheel without any fuss though. Since just blurting out the formula probably won't do much good, I have a worksheet that I've been using which might help...

http://mystang.thethirdhorse.net/mustang_wheelfit.xls

Frontspace and backspace are in millimeters. The "Allowables" are millimeters from the standard which is set by the 18x10 +45, where negatives mean there is room leftover, positives mean it is outside the allowance.

 

Thanks-awesome table.

It looks like the Enkei wheels will give me the right offset at +35.

Thanks again,

B2

 

linky no worky..

 

so the FR500s with 35+ mm will fit my car comfortably without any problems?