My 99 STS has two Goodyear Eagle LS for the rear, my front Passenger is a Eagle GA and my driver side is a Super Duty tire. All tires are from the previous owner and me being a 1st time buyer didn't even check the tires. My front passenger isn't looking too good and the GM dealer recommended all 4 were changed which didn't seem right since the rears look good to me.

Well after calling around and getting the best price for 2 Eagle LS with install for $319 for tomorrow morning, I went and checked my tire sizes on my car and I realized my tires are all 225 and not the 235 size. I am of course going to get the fronts replaced and the rears replaced in a while when I have the money.

My question is, I have no idea how long these tires have been on this car. I've owned it since May of this year. What are the issues with having a 225 vs 235 on the car other than it being the wrong size?

Also, any opinions on this tire?

Look at the driver's door sticker to find the correct OEM tire size for your car and replace all 4.

The 225-235 refers to the tire section width in mm. A 235 is the wider tire "fatness-wise". The next figure, 45,50,55 is the sidewall height in percentage of section width. You need to compare the resulting outside diameter difference between the two tire sizes. Anything over 0.4 to 0.5" introduces speedo and engine management errors due to rolling distance-per-revolution.

Sevilles came with two different wheel diameters and several different section widths, all on the same suspension/body, so the 225/235 difference will not lead to fenderwell rubbing, but check that OD - www.tirerack.com for sizing specs - compare tires and spec sheets.

I just got the new ones put on today (two).

This is my size for my car, according to Tire Rack and every where else:
235/60-16

My 225's are still 60-16 and my new ones are the correct OEM size.

225's LS' were taken from the rear and put on the front and the new ones are on the back. I still got a bit of tread left on the 225's, once they are done I will be getting another two 235's.