335/30R18 tire size

A 335/30R18 tire is 25.91 inches (658.2 mm) tall, 13.19 in (335 mm) wide and fits a 18-inch wheel. In inch notation it is roughly a 25.9x13.2R18.

335/30R18 dimensions
Overall diameter25.91 in658.2 mm
Section width13.19 in335 mm
Sidewall height3.96 in100.5 mm
Circumference81.41 in2,068 mm
Revolutions778.3 per mile483.6 per km
Rim diameter18 in457.2 mm

Compare 335/30R18 with another size

Speed in

Overall diameter difference

+1.23%

60 mph on the speedometer = 60.7 mph actual

Within the ±3 % diameter range most tire fitters accept.

Ground clearance
+4.0 mm (+0.16 in)
Revolutions
778 → 769 per mile

335/30R18 335/35R17

Side-by-side dimensions

CurrentNewDifference%
Diameter25.91 in26.23 in+0.32 in+1.23%
Diameter658.2 mm666.3 mm+8.1 mm+1.23%
Width13.19 in13.19 in0.00 in0.00%
Width335.0 mm335.0 mm0.0 mm0.00%
Sidewall3.96 in4.62 in+0.66 in+16.67%
Sidewall100.5 mm117.3 mm+16.7 mm+16.67%
Circumference81.41 in82.41 in+1.00 in+1.23%
Revs per mile778.3 768.8 −9.5 −1.22%

Speedometer error

Speedometer showsActual speedDifference
20 mph20.2 mph+0.2 mph
30 mph30.4 mph+0.4 mph
40 mph40.5 mph+0.5 mph
50 mph50.6 mph+0.6 mph
60 mph60.7 mph+0.7 mph
70 mph70.9 mph+0.9 mph
80 mph81.0 mph+1.0 mph

Plus and minus sizes for 335/30R18

SizeWheelDiameterDifference
335/35R17Minus 1 (17 in)26.23 in+1.23%
305/30R19Plus 1 (19 in)26.20 in+1.12%
325/30R19Plus 1 (19 in)26.68 in+2.95%
335/25R20Plus 2 (20 in)26.59 in+2.63%

Vehicles approved with 335/30R18 tires

Models whose Swiss type approval lists 335/30R18 as a standard or optional size (30 approvals in total). Always check your own vehicle's placard or papers.

Source: Swiss Federal Roads Office (FEDRO/ASTRA), open government data. Original data (downloaded 2026-09-29). Data processed by us; errors in processing are ours, not the publisher's.

Reading the 335/30R18 size

The load index and speed rating (for example 91V) follow the size on the sidewall. They must meet at least the values on your vehicle's tire placard.