ok this is stupid but im not sure what the measurements all mean when u look at a tire size .. xxx/xx/xx

like my tires are 255/55/16

i know the 16=16"

 

The 255 mm is the width and the 55 is the aspect ratio. What this mans is the width of the tire in proportion to the sidewall height.

The sidewall is 55% of the width or in other words 140mm thick from rim edge to the tire tread

 

ahhh ok thank you thank you, im getting new tires in a month, and i want them to be a lil wider, but i want 16"s so i dont have to change my wheels, so i would want like a 275/255/16 or something?

 

no You still have the middle aspect # wrong.

And average size tire for our car is a 245/50/16

What that means?
245mm wide at the tires widest point
50= 50% of with for sidewall height or 122.5mm thick

mm to inches is [mm divided by 25.4 = inches]

245mm divided by 25.4 = 9.65" wide tire
The rubber sidewall is 4.8" thick
The total tire height is 25.7" tall ( I just know this reference)

A larger tire would be a 255/50/16
This tire is 10.04" wide
the sidewall is 127.5mm or 5.02" thick
This tire is taller at 26" on the same 16" rim


A 245/45/17 and a 245/50/15 are the same width tires both section widths (overall width of the tire) are 245mm or 9.65" wide. The hieghts or overall diameters can be different though. But the fact is all 245 tires regardless of aspect ratio or rim size are the same section width.

 

The widest 16" tire made that you could put on our car is a 265/45/16 but you have two problems-

1) Its only availiable in that size in an "R" compound ultrasoft racing tire that would wear out very very very quickly from normal street use

2) that tire size will fit a minimum of an 8.5" wide 16" rim. Your 3rd gen stock 16" rims are only 8" wide

and I'll add a #3) fact- a 265/45/16 is a slightly shorter diamater standing at 25.2" tall instead of the 25.7-26" range these cars are designed for to keep the speedometers accurate.

 

The width on DOT tires is measured across the section of the tire not the tread. Section width can vary depending on the rim width. The same tire on a 7" rim will have a different section width as on a 10" rim. It all depends what rim width the tire measurements are based on. Typical street rims are as narrow as 5" and usually as wide as 7" with a few factory rims at 8".

The section width is in milimeters so the tire section is 255mm across. The sidewall height is 55% of that.

To find the total tire height take the section width and multiply by the ratio. 255 x 55. Divide that by 2540 to convert to inches. That's now the sidewall height. Multiply that by 2 for top and bottom and add the rim size.

255 x 55 / 2540 x 2 + 16 = 27.04" tall tire. You'll find most car tires are around 26" tall. Changing the tire height will change your speedometer accuracy. If you want a wider tire, try to find one that's the same height as the origianal ones to keep any tire swap problems to a minimum. Changing diff gears (sort of) or speedo gears can recalibrate a speedometer.

 

that was a typo in my middle number

 

i get what your saying, what would be an wide ideal tire size thats good all around

 

i think i might just buy the same size tire i have right now.... 255/55/16s , their nice size, fit my stock iroc rims and all

 

mastercraft makes a 295/50-16. looks huge on a stock wheel.

 

i was just about to suggest the 295/50/16. they are 27.7" tall and are like 10" wide tread, 12" bulge to bulge. i have seen them on stock wheels, but they wouldn't help handling much. but if it's just cruizing you want with a larger tire, i'd say go for it! a wider rim would be better down the road though, like a 16x10.

 

255/55/16 are taller than stock tires, you want to run 255/50/16 to keep the stock 26" tire diameter, and keep the sidewall smaller for better handling.

 

So anyone have pics of some 295/50/16’s on stock rims? A friend of mine has some on a set of 16x8 ARE TTII’s on his GTO and we keep talking about getting together and swapping wheels to see if they fit, but we haven’t gotten around to it.