T235/85R16 tire size

T235/85R16 in numbers

T235/85R16 works out at 31.73 inches (806 mm) tall and 235 mm (9.25 in) wide, with 199.8 mm of sidewall on each side of a 16 inch rim. One turn covers 2532 mm (99.7 in), so it turns about 395 times per kilometre and 636 times per mile, or 658 times a minute at 100 km/h. It is the tallest of the 22 temporary spare sizes listed here. At 85 series the sidewall is 0.85 times the width, 199.8 mm: 11 of the other 99 sizes on a 16 inch rim here have a taller one. The T prefix marks a temporary spare, restricted in speed and distance by design. The full-service size with the same dimensions is 235/85R16, LT235/85R16 and ST235/85R16. No other temporary spare size in this catalog comes within 3 percent of its diameter; the nearest are T155/80R19 (-9.34 percent) and T155/85R18 (-10.57 percent).

What each part of T235/85R16 means

235

Section width in millimetres, sidewall to sidewall at the widest point. Not the tread width, which is narrower.

85

Aspect ratio. The sidewall is 85 percent of the section width: 235 x 85 / 100 = 199.75 mm. A lower number is a shorter sidewall on the same width.

R

Radial construction. The R here is construction, not the speed symbol R. The speed symbol sits after the size, in the service description.

16

Rim diameter in inches. The bead seat diameter of the wheel this tire mounts on.

T

T (temporary spare). What the prefixes mean

Dimensions T235/85R16 implies

These are the nominal dimensions the size code implies. A real tire's measured dimensions depend on its mould, its construction and the rim width it is mounted on, so a manufacturer's specification sheet for a specific tire is the authority for that tire.

The overall diameter formula used here reproduces all 52 radial passenger design diameters published in an Indian vehicle standard to within 1.4 mm, 0.5 mm on average: AIS-044 (Part 2) Amendment 2, Annexure A.

Questions this size raises

What does T235/85R16 mean?

235 is the section width in millimetres. 85 is the aspect ratio: the sidewall is 85 percent of the section width, which works out at 199.8 mm. Radial construction. 16 is the rim diameter in inches. The service type is T (temporary spare).

How tall is a T235/85R16 tire?

31.73 inches (805.9 mm) in nominal overall diameter. That is the diameter the size code implies; a specific tire's measured diameter depends on its mould and the rim width it is mounted on, and the manufacturer's specification sheet is the authority for that tire.

What is the sidewall height of a T235/85R16?

7.86 inches (199.8 mm) per side.

How many revolutions per mile does a T235/85R16 turn?

636 revolutions per mile, from the nominal circumference of 99.7 inches. A loaded tire deflects and turns slightly more often than that, so a manufacturer's published revolutions figure usually runs a few percent higher.

The rest of the sidewall

The size is one line of a sidewall. What follows it decides whether the tire is legal on the vehicle at all.

• Load index table - the number after the size, and the mass it stands for. Must meet or exceed the vehicle placard.
• Speed symbol table - the letter after the load index, including the ZR, W, Y and (Y) cases.
• DOT date code - how old the tire is, and why a three digit code is not the same as a four digit one.
• Every other marking - UTQG grades, load range letters, M+S against the three peak mountain snowflake.
• Compare T235/85R16 against another size - diameter, clearance and speedometer error side by side.