#TechTip: Tire Sizes 101

Tire sizes can be confusing the first time you have to read them, so here’s a quick run-through:

Tire sizes can be confusing the first time you have to read them, so here’s a quick run-through:

What you'll see on the tire

#TechTip: Tire Sizes 101

This is a pretty standard example of what you’d find displayed on a sidewall. There are three measurements on most tires, and they refer to the following:

  1. The width of the tire (in mm)
  2. The sidewall height (displayed as a percentage of the width)
  3. The type of tire and the wheel size

Example:

#TechTip: Tire Sizes 101

Here you can see the width is 245mm or a little over 9.5”.
The sidewall is 40% of 245mm wide, putting it at about 98mm on each sidewall
The “R” stands for Radial, and the 18 represents that the tire is for an 18” wheel

Common Misconceptions

#TechTip: Tire Sizes 101

“A certain sidewall size is always the same”: Wrong. Remember that the sidewall is a percentage of the width, so a 205/45 will have less sidewall than a 295/45.

“All tire widths are created equal”: Wrong. Different manufacturers have their own biases towards actual measurements. You may find certain brands run consistently narrower or wider than others. Sidewalls should be consistent, however.

#TechTip: Tire Sizes 101

What’s your tire size? Post it below!

Sponsored Posts

Comments

ZundappDriver

2.75-17 on my moped (no sidewall size)

02/22/2016 - 16:13 |
0 | 0
DanWald

Winter tires 195/65-15
Summer tires 235/45-18

02/22/2016 - 16:13 |
0 | 0
Anonymous

2014 WRX, summer: 235/45/R17
2014 WRX, winter: 215/55/16
1997 Legacy GT Wagon, all season: 205/55/16

02/22/2016 - 16:17 |
0 | 0
Anonymous

VW Fox (br), 195/55 R15 Goodyears.
thinking about changing them to Michelin XM2 195/60 R15 due to potholes and better ride comfort .
am I thinking it right?

02/22/2016 - 16:19 |
0 | 0
Anonymous

In reply to by Anonymous (not verified)

This would increase the diameter of your wheel from 59,6 cm to 61,5 cm.
And this would be illegal in Germany…

02/22/2016 - 17:01 |
0 | 0
Arthon Tuiten

100/80/R17 in the front and 130/70/R17 in the back… #MopedLife

02/22/2016 - 16:22 |
1 | 0
Jordan Mellinger

205/50/R17 Continentals

02/22/2016 - 16:28 |
0 | 0
Clayton Hermes

225/45/17 all the way around.

02/22/2016 - 16:39 |
0 | 0
Jase Jackson

I’ve got 235/60/15 rears and 205/65/15 fronts, keeps the rears slightly taller than the front. Also, need bigger rears because RWD bro.

02/22/2016 - 16:44 |
0 | 0
Anonymous

For the 205: 185/55/14 For the Z3: summer: 225/45/17 winter: 205/55/16

02/22/2016 - 16:47 |
0 | 0
BlueOvalEnthusiast

About to buy a set of 255/85r16s

02/22/2016 - 16:49 |
0 | 0