255/70R17 in inches

31.1″ overall diameter, 10.0″ section width, 7.0″ sidewall.

	255/70R17	315/70R17	Diff
Diameter	31.1″	34.4″	+10.6%
Width	10.0″	12.4″	+23.5%
Sidewall	7.0″	8.7″
Circumference	97.6″	108.0″
Revs / mile	649	587

Recommended Tire Care & Emergency Gear

Protect your tire investment, prevent uneven tread wear, and stay prepared for highway roadside emergencies.

Driver Equipment

Roadside Power Roadside Must

NOCO Boost Plus GB40 1000A 12V Lithium Jump Starter

Ultra-compact 1000-amp lithium jump starter rated for gasoline engines up to 6 liters and diesels up to 3 liters. Delivers up to 20 jump starts per charge with spark-proof technology and reverse polarity safety protection.

Revives dead vehicle batteries instantly without needing a second jump car

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Emergency Air Pro Compressor

Heavy-Duty 12V Metal Cylinder Portable Tire Inflator

High-output direct battery clamp air compressor delivering up to 120 PSI. Inflates standard passenger tires and oversized SUV/truck tires (up to 33 inches) in minutes with thermal overload cutoff protection.

Eliminates roadside strandings and avoids coin-operated gas station air pumps

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Wheel Service Torque Spec

LEXIVON 1/2-Inch Drive Click Torque Wrench (10-150 ft-lb)

Pre-calibrated reversible click-stop torque wrench with electro-black finish and dual-range highlighted scale. Ensures wheel lug nuts are tightened to exact manufacturer torque specifications.

Prevents warped brake rotors, broken wheel studs, and loose lug nuts

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Pressure Calibration Driver Essential

AstroAI Heavy-Duty Digital Tire Inflator Gauge (250 PSI)

Commercial pistol-grip inflator gauge with backlit LCD, heavy-duty brass air chuck, and quick-disconnect bleeder valve. Delivers precise 0.1 PSI resolution for exact cold-pressure balancing.

Maximizes tire contact patch, fuel efficiency, and tread longevity

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Puncture Repair Flat Defense

Boulder Tools Heavy-Duty All-Metal Tire Plug Repair Kit

Heavy solid steel T-handle spiral reamer and split-eye insertion needle with self-vulcanizing rubber repair strings. Plugs nail punctures and screw holes in steel-belted radial tires without demounting wheels.

Permanently seals tread punctures on the shoulder in under 10 minutes

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Safety Inspection Wear Inspector

Digital Tire Tread Depth Gauge with Backlit LCD Screen

High-precision hardened probe gauge measuring remaining rubber depth in 32nds of an inch and millimeters. Features one-touch zero tare to detect early suspension camber wear.

Alerts you before tread wears past the critical 4/32" wet hydroplane threshold

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Tire Maintenance & Wheel Service Matrix

Standard vehicle maintenance intervals to maximize tread lifespan, fuel economy, and highway braking stability.

Service Task	Recommended Equipment	Service Interval	Vehicle Safety & Handling Impact
Cold Pressure Calibration	Digital Inflator Gauge (0.1 PSI resolution)	Monthly or before highway road trips	Maintains uniform footprint, avoids edge-shoulder wear, and saves fuel.
Lug Nut Torque Verification	1/2-Inch Drive Click Torque Wrench	Every tire rotation or 50 miles after wheel installation	Eliminates wheel wobble, sheared wheel studs, and warped brake discs.
Tread Depth Inspection	Digital Tread Depth Gauge	Every 3,000 miles across all 4 tires	Catches toe or camber alignment issues before tires fail wet braking tests.
Roadside Puncture Sealing	T-Handle Vulcanizing Plug Kit	On-demand when encountering road debris	Seals nail punctures in the tread crown without waiting for roadside tow trucks.
Mobile Air Delivery	12V Battery-Clamp Air Compressor	Pre-trip safety and roadside emergency inflation	Re-inflates low tires after slow bead leaks or temperature drops.
Emergency Powertrain Start	1000A Lithium Jump Pack	Vehicle emergency glovebox standby	Provides standalone cranking amps during cold morning battery drains.

Mechanic Tip

Cold Inflation Calibration Rule: Tire pressure drops roughly 1 PSI for every 10 degrees Fahrenheit drop in ambient temperature. Furthermore, driving even 1 mile generates internal friction that raises tire pressure by 3 to 5 PSI above true ambient resting level. Never set your tire pressure to the "Max PSI" molded on the tire sidewall, which indicates the maximum mechanical burst rating of the casing. Always calibrate tire pressure when the vehicle has rested for at least 3 hours, matching the cold PSI specified on the yellow-and-white driver-side door jamb placard.

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255/70R17 measures 31.1″ overall diameter and 10.0″ section width. Sidewall height is 7.0″, circumference is 97.6″, and the tire turns 649 times per mile. Those figures are geometry off the stamped size, not a brand or load range.

255/70R17 dimensions

Calculated from 255/70R17. Diameter and width are what the "in inches" search is asking for.
Measurement	Inches	Metric
Overall diameter	31.1″	789 mm
Section width	10.0″	255 mm
Sidewall height	7.0″	179 mm
Circumference	97.6″	2478 mm
Revolutions per mile	649	404 / km

The stamped width is 255 mm (10.0″). The aspect ratio is 70, so the sidewall is 70% of that width, which is 7.0″. The rim is 17 inches. Overall diameter is the rim plus two sidewalls: 17 + 2 × 7.0″ = 31.1″.

Sizes near 255/70R17

A swap that stays inside about 3% diameter usually keeps the speedometer honest and clears the same well. 275/65R17 is a close neighbour at +0.1% diameter. The percent column opens both stamps in the comparison calculator.

Catalog sizes closest to 255/70R17 by overall diameter.
Size	Diameter	Width	vs 255/70R17
275/65R17	31.1″	10.8″	+0.1%
255/75R16	31.1″	10.0″	+0.0%
265/65R17	30.6″	10.4″	-1.6%
31x10.50R15	31.0″	10.5″	-0.2%
285/65R17	31.6″	11.2″	+1.7%
265/70R17	31.6″	10.4″	+1.8%

How to read the stamped size

255/70R17 is a metric size: width in millimetres, aspect ratio as a percent of that width, then the rim diameter in inches after the R. The how to read tire size page walks the whole sidewall, including load index and speed rating, which this page does not use.

These numbers are geometry, not a fitment guarantee

Diameter and width tell you whether a size is in the same family as what you have. They do not tell you whether 255/70R17 clears your fenders, matches your wheel width, or is load-rated for the vehicle. Check the door-jamb sticker and the wheel well before you buy.

Speedometer and revs

At 649 revolutions per mile, a trip computer calibrated for 255/70R17 is reading true only while this diameter is on the truck. A taller replacement under-reads speed and distance by the same percent the diameter grew. A shorter one over-reads. The comparison calculator puts a second size next to 255/70R17 and shows the error at 60 mph.

Frequently asked questions

What is 255/70R17 in inches?

255/70R17 is 31.1″ overall diameter and 10.0″ section width. The sidewall is 7.0″. Those convert the stamped size; they are not a brand measurement.

How tall is a 255/70R17 tire?

Overall diameter is 31.1″. That is the height of the tire standing on the ground, rim plus both sidewalls.

How wide is 255/70R17?

Section width is 10.0″ (255 mm). The tread is usually a bit narrower than the section width.