255/45/17?

[Y2KSVT]

Hey guys, I know the 17" wheels are only 7.5" wide, but has anyone run a 255/45/17 tire on them? Surprisingly, I can get them cheaper than the stock 235/50/17 size. Just seeing if anyone else has run a 255 on these wheels, as I've seen a few running 245's.

Mark

[shorod]

Don't know about running a 255 width tire on the 7.5 inch wheel. However, if you run a 255/45 in place of a 235/50, you have not "plus sized" correctly. To keep the speedometer/transmission/ABS/Traction Control functioning close to correctly, you should go with a 255/40.

Is the only reason you're considering the 255/45 due to cost? Seems like safety should be the primary concern.

-Rod

[Y2KSVT]

shorod,
I think I'll have to correct you on that. A 40 series tire isn't going to be the correct height on a 255 width tire. The '40' designates the percentage of the width of the tire, in this case 255mm. For instance:

Stock: 235 x 50%(or .5) = 117.5mm
Upsize: 255 x 45%(or .45) = 114.75mm
Your suggestion: 255 x 40%(or .4) = 102mm

I called the local Discount Tire, and a 255/45/17 is a recommended size for a 17"x7.5" wheel, when the factory size is 235/50/17.

I ended up ordering some factory sized 235/50/17 Falken ZIEX ZE-512's. I've had a couple of sets of these tires on my old Contour SVT, and loved them. They were delivered today!

Mark

[shorod]

Doh, you're right. The information I was thinking of is for "plus one" sizing, going from a 17 inch wheel to an 18 inch wheel.

I understand the concept of the aspect ratio, I just should have done the math rather than relying on my memory.

Thank you for checking the information rather than taking it as gospel, and for providing the correction.

-Rod

[Y2KSVT]

Originally Posted by shorod

Doh, you're right. The information I was thinking of is for "plus one" sizing, going from a 17 inch wheel to an 18 inch wheel.

I understand the concept of the aspect ratio, I just should have done the math rather than relying on my memory.

Thank you for checking the information rather than taking it as gospel, and for providing the correction.

-Rod

Not a problem Rod! And thank you for not taking my correction, as me pointing my finger at you. Too many people on other forums who'd snap back, thinking I was trying to belittle them.

Mark