285/70R17 vs 315/70R17

Same rim, 30 mm wider, the usual 33-to-35 metric step.

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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285/70R17 vs 315/70R17 is the metric version of 33 vs 35. Same 17-inch rim, same 70-series sidewall math, 30 mm more width. Height goes from 32.7″ to 34.4″. The 315 is still not a true 35. Compare them live: 285/70R17 vs 315/70R17.

The two stamps

Same 17 in rim, same 70 aspect, width walking up.
SizeDiameterWidthSidewall
285/70R1732.7″11.2″7.9″
315/70R1734.4″12.4″8.7″

Diameter grows +5.1%. Width grows +10.5%. At 60 indicated on a truck calibrated for the 285, the 315 is doing 63.0 mph actual. That is a speedometer problem you will feel and a well problem you might hear.

What shops call them

285/70R17 is the stamp people treat as a 33 (32.7″). 315/70R17 is the stamp people treat as a 35 (34.4″). A 35x12.50R17 is the true 35, and it is also a 12.5 inch section. The 33 vs 35 page is the slang table.

Width is the filter that fails first

A 315 on a wheel that was happy with a 285 needs more rim width and more room in the well. Diameter can pass the 3% check while the sidewall kisses a liner.

Frequently asked questions

Is 315/70R17 a 35-inch tire?

No. It is 34.4″. People call it a 35 because it is the tallest common 17-inch metric on a half-ton wheel.

How much taller is 315/70R17 than 285/70R17?

+5.1% diameter, +10.5% width. About 63.0 mph actual at 60 indicated if you do not recalibrate.