Originally Posted by NWranglerS
Can someone help me understand what the "75" number means in the tires description (285/75R17E1). I read it is the aspect ratio (width divided by the height) but can someone explain to me how a 285/70R17 tire would look different than a 285/75R17 tire?
I am trying to choose between the trail grapplers 295/70R17 and 285/70R17 or 285/75R17 and don't know why I should choose one over the other
First number shows the width of the tire in mm: 285
Second number shows the sidewall aspect ratio (height) of the sidewall in percentage of the width value: 75
So, for a 285/75R17, you have a tire width of 285mm and the height of the tire sidewall is 75% of 285mm which equates to 213.75mm tall.
285mm = 11.2205 inches wide
213.75mm = 8.41535433 inches tall
So, you can take the wheel size: 17
add it to 2x the sidewall height: 16.8
and can reasonably assume the 285/75R17 tire is equivalent to a 33.8 x 11 x 17 tire.
Yeah, I know... a bit late, but none-the-less.