Tire size meaning

245/35 R18

What the numbers on a 245/35 R18 tire actually mean — width, sidewall, construction and rim — explained in plain language with real-world driving context.

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Direct answer

What does 245/35 R18 mean?

245/35 R18 is a metric tire size: 245 mm wide, a sidewall 35% of that width (86 mm), radial construction, fitted to a 18-inch wheel. Overall diameter ≈ 629 mm.

245
Section width in mm (sidewall to sidewall).
35
Aspect ratio — sidewall is 35% of width (86 mm).
R
Radial construction — the modern layered build.
18
Wheel rim diameter in inches (457 mm).

Ø 629 mm · 24.75″ · 506 revs/km

Section width 245 mmSidewall 86 mmR18 (457 mm)Ø 629 mm (24.75″)

Dimensional breakdown

Section width
245 mm
Aspect ratio
35%
Sidewall height
85.8 mm
Rim diameter
18″ (457.2 mm)
Overall diameter
629 mm
Circumference
1.975 m
Revs per km
506
Construction
Radial (R)

What 245/35 R18 feels like on the road

A 245/35 R18 tire is an ultra-low-profile performance tire. With a sidewall of 86 mm, it delivers very sharp steering response but transmits more road imperfections into the cabin and is more exposed to pothole damage.

The 245 mm contact width delivers maximum contact patch for high-performance and SUV applications. Combined with a 18-inch wheel, this size is most commonly found on mid-size sedans, sport trims and modern crossovers.

At highway speed each tire completes about 506 revolutions per kilometre — the figure your speedometer and ABS were calibrated against if 245/35 R18 is the OEM specification.

Common alternatives to 245/35 R18

Sizes within ±3% overall diameter — generally safe swaps for speedometer accuracy and clearance. Click any size to open a full side-by-side comparison.

Driver feel · telemetry

What 245/35 R18 usually feels like

A driver-perspective read on this size — steering, comfort, highway stability and rough-road behavior.

Steering feel

Sharper steering response

Short sidewall loads the contact patch fast — quick turn-in and confident on-center feel.

Ride comfort

Firmer over rough pavement

Short sidewall transmits more imperfections and increases wheel-damage risk on potholes.

Highway stability

Planted at highway speed

Wider contact patch resists crosswinds and tramlining — strong straight-line confidence.

Pothole comfort

Less margin against pothole damage

Run wider arc around potholes — short sidewall means the rim takes more of the hit.

Sporty vs OEM tone

Aggressive performance setup

A performance fingerprint — sharp, planted, low and committed.

Sidewall86 mm
Ø629 mm
Width245 mm
Revs/km506

Related tire sizes for 245/35 R18

Explore neighbouring sizes by intent — similar, wider, lower-profile, OEM-safe, or aggressive. Each link opens a full side-by-side comparison.

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Frequently asked questions