truck tire size?

[woodsracer144]

how much bigger is a 315 75 16 over a 285? I know the 16 is the rim size but i dont know what the other two numbers mean.

[kbnorth99]

The first number is the width of the tire in millimeters. The second number is the profile. That's the distance from the rim to the tread (basically the height). The profile number is a percentage of the width.

So a 315/75/16 is....
315 mm wide (12.4 inches)
236.25 mm tall from rim to tread (9.3 inches)
16 wheel.

so that that means it's a 34.6x12.4 tire

to know who much taller it is than the 285 you need know the profile as well. If its a 285/75/16 then its 32.8x11.2

Here's a good site that converts for you.


Tire size converter (http://www.therangerstation.com/tech_library/Metric_To_Inch_Tires.html)

[Ruby Soho]

yeah a 315/75r16 is equivelant to a 35x12.5r16

[wilkin250r]

Except for an online calculator like the one kbnorth99 posted, there's no real easy way, you have to do the calculations to convert from one to the other.


The first number is the width of the tire, in mm. 315mm wide.

The second number describes the height, but it's a percentage. The 75 means the height of the sidewall is 75% of the width.

The last is the rim size.

To convert mm to inches, you divide by 25.4.

Most of the time, you're interested in the height of the tire, so you multiply 315 by 0.75 and you get 236.25 That means the height from the rim to the edge of the tire is 236.25mm. To get the total height, you need to add two of these (top and bottom), plus the rim size. However, the rim size is in inches, and you're probably interested in inches anyways, so it's probably easiest to convert to inches right from the start.

So:

315/25.4 = 12.4 inches wide

12.4*0.75 = 9.301 sidewall height.

(9.301 * 2) + 16 = 34.6 inches tall. (the 16 is the tire size)

[woodsracer144]

I have 285 75 16 and want a little bigger... to gain some speed.... trucks geared low

[muddy400EX]

as long as the sidewall is the same the 315 will be bigger. but it wont be that much wider without a wider wheel

[CJM]

285s are about 32.5-33 inches or so depending on tire maker, 315's are 34-35 inches.

Best thing to do is research the tires you want and check the makers website for exact dimensions.