The journal
What does 70 mean on a tire?
On a tire, 70 is the aspect ratio: the sidewall height is 70 percent of the tire’s width. See how to read the code and check basic fitment.
It’s the aspect ratio. A 70 in a tire size means the sidewall height equals 70 percent of the tire’s nominal width shown before the slash (https://www.readingtruck.com/understanding-truck-tires-load-ratings-and-sizes/).
How to read a size like 225/70R16
In a code such as 225/70R16: 225 is the nominal width in millimeters; 70 is the aspect ratio (sidewall height as a percent of width); R indicates radial construction; and 16 is the wheel diameter in inches (https://www.readingtruck.com/understanding-truck-tires-load-ratings-and-sizes/). For sidewall height, multiply the width by 0.70. Example: 225 × 0.70 = 157.5 mm of sidewall height.
What a 70 aspect ratio means on the road
Higher aspect ratios (like 70 or 75) mean a taller sidewall that generally rides with more cushion and comfort on rougher roads. Lower aspect ratios (like 40 or 50) have a shorter sidewall that typically feels firmer and more responsive to steering inputs (https://www.duallywheels.com/blogs/guide/what-do-tire-numbers-mean?srsltid=AYCX9vI9gfSVX4gMk9UKnI_Sb3XRlZv0KhGjr_KxZH7aPUoQLiwXy05t).
Fitment basics before choosing a 70-series tire
Match what your vehicle needs
- Rim diameter must match the last number in the tire size. A 225/70R16 fits a 16-inch wheel, not a 17 or 15 (https://www.readingtruck.com/understanding-truck-tires-load-ratings-and-sizes/).
- Confirm the load index and speed rating meet or exceed the vehicle’s requirements shown next to the size on the sidewall and in your manufacturer’s recommendations (https://www.readingtruck.com/understanding-truck-tires-load-ratings-and-sizes/).
- Stick with the tire sizes and load ratings your manufacturer recommends for best results; changes in wheel size can affect vehicle handling (https://www.readingtruck.com/understanding-truck-tires-load-ratings-and-sizes/).
Quick fitment checks for a 70-series tire
Related reading from Driven & Kept
FAQ
Does 70 mean the sidewall is 70 mm tall?
No. 70 is a percentage. Multiply the nominal width (in millimeters) by 0.70 to get sidewall height (https://www.readingtruck.com/understanding-truck-tires-load-ratings-and-sizes/).
Is a 70-series tire taller than a 60-series if the width is the same?
Yes. A higher aspect ratio means a taller sidewall at the same width, which generally gives a more cushioned ride (https://www.duallywheels.com/blogs/guide/what-do-tire-numbers-mean?srsltid=AYCX9vI9gfSVX4gMk9UKnI_Sb3XRlZv0KhGjr_KxZH7aPUoQLiwXy05t).
Can I mount a 70-series tire on any 16-inch rim?
The rim diameter must match, and you should verify the tire’s load index and speed rating are appropriate for your vehicle per the manufacturer’s recommendations (https://www.readingtruck.com/understanding-truck-tires-load-ratings-and-sizes/).
