Last Updated on February 1, 2023 by Paul S.
Finding the correct size for your 35 inch tires sometimes means jumping into the metric system. Performing a straight conversion from inches into meters will not provide you with the correct information!
The quick answer to the metric size for 35 inch tires is around 315/75/R16….. but it depends! There are many different metric sizes that somewhat fit that description of a 35 inch tire. Here are some examples:
315/75/R16 295/70/R18 315/60/R20
So here is what I mean when I say they somewhat fit the description:
315/70/R17 = 34.4 inch diameter tire
295/70/R17 = 34.3 inch diameter tire
315/75/R16 = 34.6 inch diameter tire
Tire Conversion Metric to Inches
The conversion from metric is a little easier if you have those values than from diameter in inches to metric.
Let’s break the metric version down so we understand:
This number represents the tire width of the tire tread in millimeters.
This number represents the aspect ratio. The aspect ratio is the percentage of the tire width that gives you the height of the sidewall. In this case, it says 75, so that means 75% x the width (315) will give you the sidewall height. For this case, it equals 236.25 mm.
You will notice that off road vehicles have higher percentages because you want a larger sidewall height to allow for more flex in the tires, better ride in the bumps, and the more you can air down.
The last value is the diameter of the wheels. If you are going to be offroading you will stick with, 16, and 17 inch wheels depending on your tire size.
So let’s put that all together to get the diameter from the metric size of the tire. Use the following steps:
315 mm X .75 = 236.25 mm. (This is our sidewall height)
Convert to inches: 236.25 mm x (1 inch/25.4mm) = 9.3 inch
9.3 inches x 2 sidewalls = 18.6 inch
18.6 inch + R16 inch = 34.6 inch
Now you can see why it is difficult to convert from a diameter in inches to a metric size. You will need to know all of the info. Only having the diameter of the tire does you no good.
If you have the tire with you, check the side wall of the tire and that will get you the metric version of it very quickly.
Why sidewall height is important for your offroading vehicle?
The easiest way to show you why you need a larger sidewall is by photos. See below the difference between an offroad vehicle’s tires and a street car’s tires. Which one would you like to take on the trail with you?
Here are important attributes that a larger sidewall gets you out on the trail!
- Softer Ride: A larger sidewall provides more air and rubber between you and that rock. This allows a slight energy dissipation prior to the shock hitting your wheel.
- Tire Flex: With a larger sidewall the tires can mold a little easier to the trail when you air down and it gives you more assurance that you will not scrape your rims up.
- Ground Clearance: The larger sidewalls boost your ground clearance. Imagine sitting on small sidewalls! Leave that to the street lowriders!
There are many more characteristics that your tires help you get off road, like off road tire tread, but they all contribute to ripping it up and staying safe.