Buying the right size of tires can be a hassle.
There are tons of different tire widths available, and you need the exact right size for your tire.
However, the measurements of a tire differ where you live.
Since America is the only country not on the metric system, what are 35-inch tires in metric?
What Are 35-Inch Tires In Metric?
35-inch tires are about 315 millimeters in diameter. However, more calculations go into the true size of a tire. 35 inch wide tires are as wide as 315-millimeter tires, but the thickness and diameter of a tire should also be taken into consideration.
No matter where you buy tires, you have to look at all three variables, not just the width.
In this guide, I’ll teach you how to calculate the size of a tire and how to properly convert it from inches to metric form.
How do I Convert From Inches to Metric for a Tire?
When you’re getting new tires on your truck, car, or SUV, your first step is to look at what size tires you currently have.
Unless you want to pump up your car or trade tire sizes, the manufacturer generally puts the correct size of tire on.
However, if you go to buy new tires and realize that all of your calculations have been in imperial (inches and feet), you might need a metric tire calculation! Don’t get too stressed: it’s all math that can be done on your smartphone or in your head.
The simplest way to convert from inches to the metric system is to multiply the number of inches by 25.4.
This equation will give you the exact amount of millimeters.
For example, 35 X 25.4 = 889.
However, 889 is not the right number–who’s ever heard of 889 tires?
Imperial vs. Metric Systems
Knowing the difference between imperial and metric systems is vital to know what kind of tires you need.
Luckily, the difference is simple: metric tires are measured in millimeters while imperial tires are by inches.
The conversion rate is the same: divide the number of millimeters by 25.4 to get inches.
If you have inches and need millimeters, multiply the inches by 25.4 to get the number of millimeters. This equation works in every walk of life, not just with car tires.
However, the car tire ratios are a little different.
Metric Tire Measurements
Metric tire conversions are a bit trickier than simply converting from inches to millimeters.
Here’s why: the inches measurement (in this case, 35”) is the measured diameter of the tire.
However, for metric tire measurements, the measurement is the width of the tread.
This would be 315 in metric tire measurements.
It gets a little more complicated when you look at tire labels.
Where 35” tires are simply labeled with 35”, metric measured tires look like they have an entire equation for measurements.
It’s usually three numbers divided by dashes.
Don’t let this freak you out either–each of those numbers means something and will help you figure out the conversion width of the tire.
The standard metric tire size (equivalent to a 35 inch) is 315/70/17. Let’s break that down a little.
As we’ve discussed, the first number is the metric width of the tire itself.
This width is measured by the tire’s tread when looking from above.
On the top of your tire, you can measure the metric width yourself by using a tape measure that has metric measurements on it.
However, you don’t have to. A 315/70/17 tire is 315 millimeters wide.
The next number (70) represents the aspect ratio of the tire.
An aspect ratio is the height percentage of the sidewall.
Essentially, it means that the height of the sidewall is about 70% as tall as the width.
To put that in millimeters, you would multiply 315 (the width) by 0.7 (the percentage.
It comes out to 220.5 millimeters.
The third number is the wheel size in inches.
This is where you’ll need to pay attention to your specific make and model.
If your car has 17’ wheels, this tire size should work for you.
However, there are different sizes of tires for different size wheels.
On average, wheels range from 15” to 24”, although most are within the 16-18” range.
Converting it to Inches
We have the size of the sidewall (220.5 millimeters) and the size of the wheel (17”).
All we need to do now is convert the sidewall to inches, and we’ll find out the diameter of the entire tire (and thus, the measurement in imperial standard).
220.5 is only one length of the sidewall.
Double that, and you have 441, which provides the rest of the diameter. 441 divided by 25.4 is approximately 17.36.
That is the size of both sides of drywall in inches. Add 17.36” to 17” of the wheel and you have a little above 34”.
Of course, companies would rather have an even number, so we round up to 35”.
Imperial Tire Measurements
Imperial tire measurements are much simpler than metric.
They are measured by the tire diameter, including the wheel area.
For 35” tires, this is just 35 inches from top to bottom.
It might be easier, but it doesn’t have as many specifications as metric measurements.
What makes things more complicated is that every tire company has slightly different molds.
While the industry standard for a 35” tire is the 315/70/17 metric measurement, it doesn’t mean that every tire is the same.
This difference isn’t something to worry too much about–unless your car is a specialty car, you can use just about any tires and be fine.
Focus on getting the right standard size for your vehicle, and you won’t need to worry about the minuscule differences in tire sizes.
You can compare exact measurements on company sizes.
Of course, you might have to calculate things a little differently if you’re lifting your tires or putting monster truck tires on your car.
This involves specialty tires, and you’ll have to make adjustments to your vehicle itself.
In some cases, you might need to regear the undercarriage to make larger tires work.
Specialty tires involve specific vehicles and purposes.
If you’re trying to add lift to a truck for off-roading, it will be different if you just want larger tires for show or height.
No matter what kind of tires you order, the inches to millimeters measurements will be the same.
You might have to jump through some mathematical hoops to figure it out, but it will still work!
Unless you have specialty tires and need a specific lift height, you can simply buy manufacturer tires and not worry about converting from inches to millimeters too often.
Most tire companies will provide a chart that measures equivalents, so you don’t have to do the math yourself.
While the imperial to metric conversion isn’t too difficult, it is complicated by the number of calculations in a metric tire.
However, with this guide or an equivalency table, you’ll be able to figure out exactly what size the tire is and whether it will work for your car.