285/70R17 in Inches

285/70R17 and seven nearby 17-inch tire sizes

Every percentage uses 285/70R17 as the original reference. Positive values identify a taller candidate; negative values identify a shorter one. Diameter is shown in both inches and millimeters, and section width is converted to inches. These are metric size alternatives for geometric comparison; sharing a 17-inch bead diameter does not establish wheel-width or vehicle compatibility.

Read the width, aspect ratio and wheel diameter

The first number, 285, gives nominal section width in millimeters. Divide by 25.4 to express that width in inches. Section width is not tread width: shoulder shape and the measuring rim influence the dimensions published for an exact tire. The middle number, 70, means the sidewall height is 70 percent of the section width. It is a ratio, rather than a sidewall measurement in millimeters.

One sidewall is therefore 285 times 70 divided by 100, or 199.5 mm (7.85 inches). The wheel contributes 431.8 mm. Adding two sidewalls gives 830.8 mm overall diameter. R identifies radial construction, and 17 specifies wheel bead diameter in inches. Neither the letter R nor the final number describes the outer tire radius.

Circumference and revolutions per mile

Multiplying the unrounded outer diameter by pi gives a nominal circumference of 2610.0 mm, or 102.76 inches. Dividing 1,609,344 millimeters per mile by that circumference gives 616.6 revolutions per mile. Keep full precision through the calculation and round only the displayed result; using the rounded 32.7-inch label would introduce a small avoidable difference.

These revolutions describe an ideal circular tire calculated from its marking. Manufacturer rolling data can differ because construction, inflation pressure, load and tread affect the tire in service. A loaded radius is a separate measurement. Use the published specification for the exact tire when comparing product dimensions or measured rolling revolutions, and compare figures obtained under comparable conditions.

Is 33x11.50R17 or 34x11.50R17 closer?

Of those two nominal flotation labels, 33x11.50R17 is closer in outer diameter. Its stated height is 0.29 inches taller than 285/70R17, while 34x11.50R17 is 1.29 inches taller. Both labels specify 11.50 inches of width, which is 0.28 inches wider than the metric size's nominal section width.

Calling 285/70R17 a 33-inch tire is a coarse category description, not an exact conversion. Its calculated height falls between 32 and 33 inches and nearer 33. A flotation label supplies overall diameter directly, whereas a metric label requires calculating two sidewalls first. Neither label proves that an exact product exists in a particular catalog or that it can replace a vehicle-approved size.

Compare 265/70R17, 285/75R17 and 295/70R17

Compared with the 285/70R17 reference, 265/70R17 is 1.10 inches shorter (-3.37%). At an indicated 60 mph, the calculated actual speed becomes 57.98 mph. Keeping the same aspect ratio while reducing width also shortens the sidewall, so changing width alone changes overall height. The linked 265/70R17 versus 285/70R17 comparison lets you inspect that pair in more detail.

The 285/75R17 candidate is 1.12 inches taller (+3.43%); its calculated actual speed at an indicated 60 mph is 62.06 mph. The 295/70R17 candidate is 0.55 inches taller (+1.69%), with 61.01 mph actual at the same indication. All comparisons here start from 285/70R17. Reversing original and candidate changes the percentage denominator, so do not simply reuse the same percentage for the reverse swap.

Understand speedometer direction before choosing a size

With a taller tire, the speedometer reads lower than actual speed, assuming calibration to the original tire and no other instrument error. Each revolution covers more distance. Actual speed equals indicated speed multiplied by candidate diameter divided by original diameter. A shorter tire reverses that geometric effect. Existing factory calibration and vehicle sensor processing remain separate from this nominal comparison.

A diameter difference also changes the nominal distance covered per wheel revolution and can affect odometer readings. Before choosing among the table rows, record the original axle sizes, wheel width, offset and exact service description. Check clearance through steering and suspension travel, then investigate the specific tire product. The calculator is useful for exploring another pair; a close percentage alone does not settle those vehicle-specific questions.

Frequently asked questions

How tall is 285/70R17 in inches?

Nominal overall diameter is 32.71 inches, commonly rounded to 32.7 inches. This includes the 17-inch wheel and both calculated sidewalls. An exact manufacturer's published outside diameter may differ from nominal geometry.

How wide is a 285/70R17 tire?

The marking specifies 285 mm of nominal section width, equal to 11.22 inches. That is not a direct measurement of tread width or a statement that every 17-inch wheel has an approved width for this tire.

Is 285/70R17 exactly a 33-inch tire?

No. Its calculated diameter is slightly below 33 inches and closer to 33 than to 34 inches. Use the full metric code when comparing actual products, and treat a rounded inch category as an approximate description.

Does 285/75R17 have the same height because the width matches?

No. The 75 aspect ratio makes each sidewall taller than the 70 aspect ratio at the same 285 mm width. The diameter increases even though the wheel diameter and nominal section width stay the same.

Continue your comparison

• Compare 265/70R17 versus 285/70R17
• Calculate your exact original and candidate sizes
• Learn how to convert metric tire sizes to inches