1989 mustang gt 18" tire info needed!!
 

Hi everyone I am new to the forums but I do always read them and swear they are my lone source of great info,upgrades etc.I have an 89 Mustang get w40k miles on it,I've converted it from auto to manual,new Ford racing engine and t5.I now am at the stage of purchasing new Tires,the car has a sn95 front spindles and North race car cobra conversion w/fox length axles.I have 18 x 9 black Saleen rims with 30mm offset and 6.18 backspace,Also the car has new Moog stock height coil springs.I was hoping somebody out there can help me choose tire sizes for front and rear,I was thinking 245/35 front and 275/35 rears.I appreciate any help as if I buy the wrong size I will not be able to return the tires.Thank you so much and sorry couldn't find anything for stock height.

245/35 is a bit short on the front, maybe look at 245/40 or 255/35. The problem with having very short sidewall tires on a stock ride height car is the fender gap looks disproportionately large. 245/40 and 275/35/18 will be almost identical to the overall diameter of the original 225/60/15 tires, but will look shorter on the car because of the ratio of rubber to rim ... it's going to look like the car is actually "lifted".


cheers
Ed

Thank you fast ed,The car was lowered when I bought it its just I live on an acreage where the road is crappy and Made the decision to go back to stock height.I guess 245/40 front and 275/40 rear is best option with my setup?I guess I could go 1 size taller to fill the gap but then its gonna look like a 4wd.Either way Thanks a bunch for your info,I really do appreciate the help.

The problem with getting too much taller with that extra width, you may get in to rubbing on the fenders. 245/40/18 is stock diameter, 275/40 is about an inch taller. If you want the same height all around with staggered widths, the aspect ratio has to be lower on the rear to get the same sidewall height.

Take a look at a site like this to compare various sizes:

https://tiresize.com/calculator/

IMO, you might be better off to put the same size all around, maybe something like 255/40/18 which is going to be roughly 26.0" diameter vs. the stock 25.7". My guess is that 275/40/18 would rub on the back without some serious fender lip trimming or rolling.


cheers
Ed

Thanks for the link to that Website,also I think that's a good plan with the 255/40/18 all the way around & That way I can rotate them as well.Thanks again fast ed,I will let you know what I decide in the end and you have yourself a good weekend.