2021 Ford Mustang tire size

Most common factory size

P265/35R20

Tire sizes by trim

Source marks: one source

2021 Ford Mustang tire size by trim
Size	Trims	Width, mm	Sidewall, % of width	Rim, in	Diameter, in	Sidewall, in	Revs per mile
P265/35R20	EcoBoost Premium RWD, GT Premium RWD	265	35	20	27.30	3.65	739
P255/40R19	EcoBoost RWD	255	40	19	27.03	4.02	746

What P265/35R20 means
Part	Number	Meaning
Type	P	Passenger car tire.
Width	265 mm	Tread width. 10.4 in.
Sidewall	35	Sidewall height is 35% of the width.
Construction	R	Radial tire.
Rim	20 in	Fits 20 in wheels.

Within 3% of the stock diameter. A common shop guideline, not a maker spec.

Sizes within 3% of P265/35R20
Size	Rim, in	Diameter, in	Change	Speedo reads at 60 mph
235/45R19	19	27.33	+0.1%	59.9 mph
265/40R19	19	27.35	+0.2%	59.9 mph
235/40R20	20	27.40	+0.4%	59.8 mph
305/30R20	20	27.20	-0.4%	60.2 mph
295/35R19	19	27.13	-0.6%	60.4 mph
275/30R21	21	27.50	+0.7%	59.6 mph
155/70R19	19	27.54	+0.9%	59.5 mph
255/40R19	19	27.03	-1.0%	60.6 mph

Sizes within 3% of P255/40R19
Size	Rim, in	Diameter, in	Change	Speedo reads at 60 mph
255/35R20	20	27.03	-0.0%	60.0 mph
255/45R18	18	27.04	+0.0%	60.0 mph
225/45R19	19	26.97	-0.2%	60.1 mph
295/35R19	19	27.13	+0.4%	59.8 mph
225/50R18	18	26.86	-0.6%	60.4 mph
305/30R20	20	27.20	+0.6%	59.6 mph
235/50R18	18	27.25	+0.8%	59.5 mph
265/35R20	20	27.30	+1.0%	59.4 mph

Checked against 292 factory sizes listed for 2009-2027 US models.

Tire pressure is on the driver door sticker. Not in this data.

Optional wheel packages may differ.