How many inches is a 235 tire


Tire Size Calculator | Quadratec


How to Understand Your Current Tire Size

Knowing your Jeep's tire size can be essential information when it comes time to replace that rubber, or even if you ever decide to change wheels. And while a stock tire size is imprinted right inside the driver side B pillar, you may not know what if have if you are not the original owner.

So here is some helpful information to assist you in determining what you currently have on the vehicle.

First, the sidewall of your tire contains all the information needed to understand everything about that specific tire. All tires are required to have this information, regardless of the manufacturer brand name.

Now, this information could read in a few different ways. For example, it could simply say 35x12.5 R17, or it may show as P265 75 R15. If it is the first listing, then here is the breakdown. That first number is your tire size at 35", and then the second number tells you the tire width at 12. 5". That third reading is the tire type as radial and diameter as 17".

The second listing is a metric set up, and is what is more common on factory-type sized tires. From left to right, the P indicates a passenger tire while 265 indicates the tires width in millimeters. That 75 is the tire's aspect ratio and simply means the tire's height is equal to 75 percent of its width. Finally, like the first set of numbers, that R15 means it is a radial tire and has a 15" diameter.

For those who have the metric reading on their tires, you can simply plug that into the conversion calculator to determine the tire size, or find that corresponding reading on one of the below conversion charts.

Metric to Standard Conversion

Enter the metric size (i.e. 285/75 R17)

15-inch Wheel Conversion Chart

Metric to Standard Tire Conversion Chart for 15 inch Wheels
Metric Standard
215/75/15 27. 7"x 8.5"
225/70/15 27.4"x 8.9"
225/75/15 28.3"x 8.9"
235/75/15 29.0"x 9.3"
245/75/15 29.5"x 9.6"
255/75/15 30.0"x 10.0"
265/75/15 30.6"x 10.4"

16-inch Wheel Conversion Chart

Metric to Standard Tire Conversion Chart for 16 inch Wheels
Metric Standard
205/85/16 29.7"x 8.1"
215/75/16 28.7"x 8.5"
225/70/16 28.4"x 8.9"
225/75/16 29.2"x 8.9"
235/70/16 29.0"x 9.3"
235/85/16 31.7"x 9.3"
245/70/16 29.5"x 9.6"
245/75/16 30.5"x 9.6"
255/70/16 30.0"x 10.0"
265/70/16 30. 6"x 10.4"
265/75/16 31.6"x 10.4"
275/70/16 31.2"x 10.8"
285/75/16 32.8"x 11.2"
295/75/16 33.4"x 11.6"
305/70/16 33.0"x 12.2"
315/75/16 34.8"x 12.4"
375/55/16 32.8"x 15.5"
395/70/16 37.9"x 16.0"

17-inch Wheel Conversion Chart

Metric to Standard Tire Conversion Chart for 17 inch Wheels
Metric Standard
245/70/17 30.6"x 9.8
265/70/17 31.6"x 10.7
285/70/17 33.0"x 11.5
315/70/17 34.4"x 12.4

18-inch Wheel Conversion Chart

Metric to Standard Tire Conversion Chart for 18 inch Wheels
Metric Standard
275/65/18 32. 1"x 11.0
375/50/18 33.0"x 15.4
325/60/18 33.2"x 13.3
325/65/18 34.8"x 13.5
305/70/18 35.0"x 12.2
375/60/18 35.7"x 15.5
395/65/18 37.8"x 15.7

20-inch Wheel Conversion Chart

Metric to Standard Tire Conversion Chart for 20 inch Wheels
Metric Standard
325/50/20 33.0"x 13.2"

Metric measurement example: 225/70R15

225 = Section width in millimeters

70 = Aspect ratio (ratio of section height to section width)

R15 = Rim diameter

R = Radial Construction, B = Bias Construction, D = Bias Belted Construction


Calculations for Measurements

Tire Width: Section width divided by 25.4 (Ex: 225 / 25.4 = 8.86")

Section Height: Tire width times aspect ratio (Ex: 8. 86" x 70% = 6.20")

Overall Diameter: Section height times 2 plus rim diameter (Ex: (6.20" x 2) + 15 = 27.40")

See all tires here


Related Articles:

When Is It Time To Change My Jeep's Tires?

Choosing The Best Jeep Tires

How Do You Rotate Jeep Tires?

P-Metric Tire Sizes – P-Metric to Inches Conversion Chart |

Offroaders Staff Technical & Info

Offroaders.com Guide to P-Metric Tire Sizes, Conversion Chart and Tire Terminology – P-Metric to Inches

The following chart lists common p-metric tires sizes and the converted tread width and the actual tire height in inches.  The values shown are calculated measurements based on the p-metric formula, which is explained below on this page.  This chart is for an estimated conversion and the actual advertised tire height and tread width will vary from manufacturer to manufacturer. If you need to know the actual p-metric tire size and the equivalent measurements in inches for a specific tire, check with the manufacturer’s actual dimensions per individual tire brand before purchasing. 

Rim SizeP-Metric SizeTread WidthActual Tire Height
15 Inch205/70R158.0 inches26.3 inches
215/75R158. 46 inches27.7 inches
235/75R159.25 inches28.9 inches
265/70R1510.4 inches29.6 inches
16 Inch225/75R168.8 inches29.3 inches
235/85R169.25 inches31.7 inches
245/75R169.6 inches30.5 inches
265/70R1610. 4 inches30.6 inches
265/75R1610.4 inches31.6 inches
285/75R1611.2 inches32.8 inches
305/70R1612.0 inches32.8 inches
315/75R1612.4 inches34.6 inches
345/75R1613.6 inches36.4 inches
17 Inch235/65R179. 25 inches29.0 inches
245/70R179.6 inches30.5 inches
255/75R1710.0 inches32.0 inches
255/80R1710.0 inches33.0 inches
265/70R1710.4 inches31.6 inches
275/70R1710.8 inches32.2 inches
285/70R1711.2 inches32. 7 inches
285/75R1711.2 inches33.8 inches
305/65R1712.0 inches32.6 inches
315/70R1712.4 inches34.4 inches
18 Inch265/60R1810.4 inches30.5 inches
275/65R1810.8 inches32.1 inches
275/70R1810. 8 inches33.2 inches
285/75R1811.2 inches34.8 inches
295/65R1812.6 inches33.1 inches
305/60R1812.0 inches32.4 inches
305/70R1812.0 inches34.8 inches
20 Inch275/60R2010.8 inches33.0 inches
275/65R2010. 8 inches34.0 inches
285/60R2011.2 inches33.4 inches
285/65R2011.2 inches34.5 inches
295/55R2012.6 inches32.8 inches
295/60R2011.6 inches33.9 inches
305/55R2012.0 inches33.2 inches
325/60R2012.8 inches35. 3 inches

 

Other 4×4 Related Calculators

▪ Convert P-Metric Tire to Inches
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▪ Speedometer Converter
▪ Find new Gear Ratio with new Tire Size
▪ Find Overall Crawl Ratio
▪ Find MPH
▪ Find RPM
▪ Convert P-Metric Tire to Inches

 

All tires are required to have certain information molded into the side of the tire in a location known as the sidewall.  Some of the information is self explanatory while other information requires a little knowledge to decipher.  The following will help you understand what this information means.

Tire Type – This Defines the intended proper use of the tire. P indicates this is a passenger car tire while LT indicates the tire would be for a light truck with a heavier load rating.

Tire Width – This is the width of the tire measured in millimeters from sidewall to sidewall.   An example might be 215 representing 215 millimeters.

Aspect Ratio – This is the ratio of the height of the tire’s cross-section to its width. An example of this might be 65, which means that the height is equal to 65% of the tire’s width.  To calculate the aspect ratio, multiple the first number (e.g. 215) by the second number with a decimal before the number (e.g. .65).  Using the example numbers the tires aspect ratio would calculate as 215x.65=139.75 where 139.75 is the tires height in millimeters.  This is the height of the rubber from rim to tread on one side of the tire. 

To convert the aspect ratio to a full tire height in inches, do this:
Convert the above calculated tire height (aspect ratio) in millimeters to inches by multiplying the millimeters by .03937 (139.75 x .03937 = 5.5 inches).  Then take the inches and multiply by two and add the rim size. Example: 5.5 x 2 + 15 (rim size in inches) = a 26 inch tall tire.

Construction – This indicates how the how the tire was put together and will say much about the tires handling characteristics. R indicates the tire is a radial type tire.  For more information about what a radial is, click here.  B indicates the tire is a bias ply type tire.  For more information about bias ply type tires, click here.

Wheel Diameter – This is the width of the opening in the tire where it would be mounted to a wheel.  This is measured from one bead across the opening to the other side of the same bead.  This measurement is in inches and an example would be 15 and indicates that this tire is for a 15 inch rim, or wheel.

Load Index – This is a number corresponds to the maximum load in pounds that a tire can support when properly inflated. You will also find the maximum load in pounds and in kilograms molded elsewhere on the tire sidewall.

Speed Rating – This is a number that corresponds to the maximum service speed for a tire.   See Chart for ratings.  Note: Speed ratings are specific for passenger car tires and not light truck tires.  Light truck tires (LT) are not speed rated. 

Rating

Maximum Speed
Q99 mph
S112 mph
T118 mph
U124 mph
H130 mph
V149 mph
W168 mph
Y186 mph
ZAbove 149 mph

 

Related Articles

235/85 R16 vs 235/85 R15 Graphic tire size comparison (difference in inches)

Your machine size

/ 253035404550556065707580859095100 R 121314151617181920212222. 52324

Calculate

135145155165175185195205215225235245255265275285295305315325335345355365375385395 / 253035404550556065707580859095100 R 121314151617181920212222.52324

New tire size

CM INCHES


Index Old New Difference
Diameter - - -
Width - - -
Circumference - - -
Profile height - - -
RPM - - -
Clearance change -
Result: -

With speedometer:

Real speed will be:

Comparison of tire sizes 235/85 R16 and 235/85 R15.

In the table above you can see a detailed comparison of the difference in dimensions, parameters and performance between a 235/85 R16 tire and a 235/85 R15 tire. The results of the calculations are also presented in the form of visual models (infographics), on which the tire with a size of 235/85 R16 is on top, and with a size of 235/85 R15, respectively, at the bottom. The visualization was generated in two projections: lateral (left) and frontal (right). The online calculator compares tires according to the following characteristics: diameter, width, circumference, profile height, revolutions per km, ground clearance change. In addition, a potential deviation between the actual speed and the speed displayed on the speedometer is calculated, which can occur if the difference between tires 235/85 R16 and 235/85 R15 is significant. US and UK inch version of calculations.

If you want to compare other tyres, just select the required parameters in the drop-down fields and click on the green button.

Infographic

Side Comparison Frontal comparison

See also:

Tire calculator inches

American and European tires are distinguished by their markings. European tires have a metric marking system. Therefore, when replacing tires, the problem of translating tire parameters may arise. In most cases, this is the conversion of inches to centimeters. Enter the size in inches and click calculate. You will see the tire size in meters (dimensions will be rounded to European parameters).

US size
Metric size
Rounded to European standard

Comparison: inches and meters

When you enter the old inch parameters and new European ones, you can see how the external parameters of the tire and ground clearance will change, as well as differences in the speedometer readings.

Old size: 27293031323335373840 / 8.59.510.511.512.513.514.515.5 R 14151616.517182022
New size: 145155165175185195205215225235245255265275285295305315325 / /253035404550555606570758085 R 12131415161718192021222324
Tire width mm (A)
Profile height mm (B)
ID mm (C)
OD, mm (D)
Speedometer (km/h)
Real speed (km/h)
Difference (km/h)

Ground clearance (mm)

Metric to Inch Tire Size Conversion (US)

Thanks to the Tire Calculator, you can do the reverse calculation - convert "cm" and "mm" to inches.


Learn more