I have a chance to get a set of nice chrome stock sts rims and nexen n5000 for $100 for the set. the tires are 235/60-16 and i wanted to know if the extra half inch will fit. I also wanted to know if it would increase my highway gas mileage or throw off my speedometer. Here are some specs from another website that compares tire sizes and calculates the difference.
Tire size calculator

Tire size calculator

Tire Size Comparison

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference 225/60-16 5.3in 13.3in 26.6in 83.7in 757 0.0% 235/60-16 5.6in 13.6in 27.1in 85.1in 744 1.8%

 

what bolt pattern do they have?

make sure it's 5x115 or 5x114.3

They are small enough to where it shouldn't affect you speedometer but it still may affect it just slightly.

As for you highway gas mileage?? there's only one way to really find out and that's trying them. Are they lighter than the rims on there now?

 

The sts is a rear wheel drive car so the backspacing may not work.

 

I measured the back spacing and the STS rim is only 3/16 deeper. I put one on the rear and they seemed to fit fine. No rubbing when I spun the wheel and I still had a half inch or more between the strut tower and the tire edge.
I think they will be fine. They Look great compared to the bottle caps that were on the car. Much wider and flatter tread on the nexens.

 

there's a monte by me i always see on oem caddy rims but i think they're dts rims