275/35R21 in inches

A 275/35R21 tire is 28.6″ tall and 10.8″ wide, and fits a 21″ wheel. In inches it is written 28.6×10.8R21.

Diameter28.58″

Width10.83″

Sidewall3.79″

Drawn to scale. Nominal dimensions calculated from the size code.

Manufacturer data

How tall 275/35R21 tires really are

Heights published by Michelin and Toyo for all 24 tires in this size. Their published revolutions per mile work out to 27.7″ under load (below).

Real 275/35R21 tires measure 28.50–28.60″, against 28.58″ from the size code. Most run shorter than the size code (23 of 24).

Height under load27.7″

Published revs per mile (728–729) mean the tire rolls like a 27.7″ tire on the vehicle. Use this for speedometer calibration.

Weight spread26.7–34.6 lb

The lightest (Michelin Pilot Sport 4 S, XL) is 7.9 lb lighter per corner than the heaviest (Michelin Pilot Super Sport, SL).

24 tires in 275/35R21

Sort by the spec you care about.

	Load					Revs/mi	Source
Michelin Pilot Sport 4 SPerformance	XL · 103(Y)	28.50	26.7	9.0	1,929	729	Spec page
Michelin Pilot Sport S 5Performance	XL · 103(Y)	28.50	27.2	9.0	1,929	729	Spec page
Michelin Pilot Sport Cup 2Performance	XL · 103(Y)	28.50	27.6	7.2	1,929	729	Spec page
Michelin Pilot Sport S 5Performance	XL · 103(Y)	28.50	27.7	9.0	1,929	729	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 103(Y)	28.50	27.9	9.0	1,929	729	Spec page
Michelin Pilot Sport S 5Performance	XL · 103(Y)	28.50	27.9	9.0	1,929	729	Spec page
Michelin Pilot Sport S 5Performance	XL · 103(Y)	28.50	28.3	9.0	1,929	729	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 103(Y)	28.50	28.6	9.0	1,929	729	Spec page
Michelin Pilot Sport Cup 2 ConnectPerformance	XL · 103(Y)	28.50	28.7	7.2	1,929	729	Spec page
Michelin Pilot Sport S 5Performance	SL · 99Y	28.50	28.8	8.5	1,709	729	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 103(Y)	28.50	29.1	9.5	1,929	729	Spec page
Michelin Pilot Sport 4 SPerformance	XL · 103(Y)	28.50	29.6	9.5	1,929	729	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 103Y	28.50	29.9	10.0	1,929	729	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 103W	28.50	29.9	9.0	1,929	729	Spec page
Michelin Pilot Alpin 5Winter	XL · 103V	28.54	30.0	9.5	1,929	729	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 103V	28.50	30.1	9.5	1,929	729	Spec page
Michelin Pilot Sport All-Season 4Performance	XL · 103V	28.50	30.4	9.5	1,929	729	Spec page
Michelin Pilot Sport 4Performance	XL · 103(Y)	28.50	30.8	9.5	1,929	729	Spec page
Michelin Pilot Sport S 5Performance	XL · 103(Y)	28.60	30.9	9.0	1,929	729	Spec page
Toyo Proxes Sport 2Performance	XL · 103(Y)	28.50	31.1	9.2	1,929	728	Spec page
Michelin Primacy Tour A/STouring	XL · 103V	28.50	31.1	9.0	1,929	729	Spec page
Michelin X-Ice Snow+Winter	XL · 103H	28.54	32.4	10.5	1,929	729	Spec page
Michelin Pilot Sport EVPerformance	XL · 103Y	28.50	32.6	8.5	1,929	729	Spec page
Michelin Pilot Super SportPerformance	SL · 99Y	28.50	34.6	9.5	1,709	729	Spec page

Is 275/35R21 a 29-inch tire?

≈29″

Close. The size code works out to 28.58″, and the 24 tires here publish 28.50–28.60″, so people call it a 29.

All 29-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

Size	Diameter ″	vs 275/35R21	Difference
255/35R21	28.03	-0.55″	-1.9%
305/30R21	28.20	-0.37″	-1.3%
265/35R21	28.30	-0.28″	-1.0%
315/30R21	28.44	-0.14″	-0.5%
325/30R21	28.68	+0.10″	+0.3%
245/40R21	28.72	+0.14″	+0.5%
285/35R21	28.85	+0.28″	+1.0%
335/30R21	28.91	+0.33″	+1.2%
225/45R21	28.97	+0.39″	+1.4%
255/40R21	29.03	+0.45″	+1.6%

How to read 275/35R21

How to read any tire size

How 275/35R21 103Y is printed on the sidewall. It's the most common code among the 24 tires here (14 of them); tires in this size come in other load and speed ratings too.

1275Section width

275 mm across the widest point, or 10.83 inches. Every 275 size

235Aspect ratio

A percentage, not a measurement: the sidewall is 35% as tall as the tire is wide, which is 96.3 mm or 3.79 inches.

3RConstruction

Radial construction.

421Wheel diameter

Mounts on a 21-inch wheel. Approved wheel widths run 9.0″ to 11.0″.

5103Load index

Each tire carries up to 1,929 lb (875 kg) at its maximum pressure.

6YSpeed rating

Rated for up to 186 mph sustained.

XLExtra load

Printed after the size. In this size the XL tires carry up to 1,929 lb each and the standard-load tires up to 1,709 lb, as published.

Specification	Inches	Metric
Overall diameter	28.58	726 mm
Section width	10.83	275 mm
Sidewall height	3.79	96.3 mm
Circumference	89.8	2,280 mm
Revolutions per mile (calculated, unloaded)	705.7	439 per km
Revolutions per mile (published by manufacturers)	728–729	452–453 per km
Approved wheel width	9.0–11.0	229–279 mm

Speedometer error after switching to 275/35R21

Your actual speed– mph

Questions about 275/35R21

What is 275/35R21 in inches?

28.58 inches tall, 10.83 inches wide, on a 21-inch wheel. Written in inches, that is roughly 28.6×10.8R21.

How much does a 275/35R21 tire weigh?

Between 26.7 lb and 34.6 lb for the 24 tires listed here. The lightest is the Michelin Pilot Sport 4 S (XL); the heaviest is the Michelin Pilot Super Sport (SL).

What wheel width do I need for 275/35R21?

Manufacturers approve 9.0–11.0″ wide wheels for this size.

How many revolutions per mile does a 275/35R21 make?

Published figures run 728–729 revolutions per mile. The calculated figure is 705.7, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 275/35R21 than 315/30R21?

0.14 inches taller on paper (28.58″ vs 28.44″), which raises the axle about 0.07″. Your speedometer will read about 0.5% slow.