265/40R21 Tire Size Specifications & Compatible Vehicles
Overall Diameter
745.4 mm
Section Width
265 mm
Sidewall Height
106.0 mm
Circumference
2341.7 mm
Revs/Mile
687
Rim Diameter
21"
Inch Equivalent
29.3x10.4R21
Rim Width (ETRTO)
7.5" – 10.0"
Alternative Tire Sizes
These tire sizes are within 3% overall diameter of 265/40R21 and may be used as replacements:
Popular Comparisons
See how 265/40R21 compares to other common tire sizes:
Understanding 265/40R21
The tire size 265/40R21 means the tire has a section width of 265mm, an aspect ratio of 40% (the sidewall height is 40% of the width), and fits a 21-inch rim.
Sidewall Height = 265 x 0.4 = 106.0 mm
Overall Diameter = (106.0 x 2) + (21 x 25.4) = 745.4 mm
Circumference = 745.4 x π = 2341.7 mm
Overall Diameter = (106.0 x 2) + (21 x 25.4) = 745.4 mm
Circumference = 745.4 x π = 2341.7 mm
Frequently Asked Questions
The 265/40R21 is a standard tire size. Check your vehicle door jamb sticker or owner manual to confirm compatibility.
A 265/40R21 tire has an overall diameter of 745.4mm (29.3 inches). The sidewall height is 106.0mm, and the total circumference is 2342mm.
For 265/40R21 tires, the ETRTO recommended rim width is 9.0". The acceptable range is 7.5" minimum to 10.0" maximum. Using a rim outside this range can cause improper bead seating and unsafe handling.
Yes, as long as the replacement tire overall diameter is within 3% of the 265/40R21 745.4mm diameter. Compatible alternatives include 175/75R19, 235/45R21, 155/60R22. Use our Tire Size Calculator to compare any two sizes.