What is the diameter of a 265/45R18 tire?

A 265/45R18 tire has an overall diameter of 27.39 inches (695.7mm).

How many revolutions per mile does a 265/45R18 tire make?

A 265/45R18 tire makes approximately 736 revolutions per mile.

What rim width is recommended for 265/45R18 tires?

The recommended wheel rim width for a 265/45R18 tire is 6.6" - 9.3".

265/45R18

Standard Metric

Factory Specs, Physical Dimensions & Compatible Vehicle Applications

Factory Spec Overview

The 265/45R18 tire size features an overall diameter of 27.39 inches, a section width of 10.4 inches (265mm), and rotates 736 times per mile. It is a standard factory tire fitment on 54+ vehicle models including Cadillac CT6, Porsche Boxster.

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Physical Dimensions & Specs

Overall Diameter

27.39"

695.7 mm

Section Width

265 mm

10.43" wide

Sidewall Height

4.69"

119.1 mm (45% aspect)

Revolutions / Mile

736

Circumference: 86.05"

Rim Diameter

18"

Wheel size

Recommended Rim Width

6.6" - 9.3"

Optimal rim width range

Speedometer & Alternate Size Calculator

Testing an alternate size for your vehicle? Compare 265/45R18 against any proposed tire size below:

Popular Comparisons:

Tire 1 (Stock / Base)265/45R18

Section Width (mm)

Aspect Ratio (%)

Rim Diameter (in)

Wheel Width (in)

Offset ET (mm)

Overall Height:27.4"

Sidewall:4.7"

Revs/Mile:736

Tire 2 (New / Compare)245/60R18

Section Width (mm)

Aspect Ratio (%)

Rim Diameter (in)

Wheel Width (in)

Offset ET (mm)

Overall Height:29.6"

Sidewall:5.8"

Revs/Mile:682

Visual Tire & Wheel Comparison

Speedometer Variance

+8.0%At 60 mph reading, actual speed is 64.8 mph

Indicated	Actual Speed	Diff
20 mph	21.6 mph	+1.6 mph
30 mph	32.4 mph	+2.4 mph
45 mph	48.6 mph	+3.6 mph
60 mph	64.8 mph	+4.8 mph
75 mph	81.0 mph	+6.0 mph
90 mph	97.2 mph	+7.2 mph

Fender & Suspension Clearance

Fitment Status: MODERATE RISK

Flush fitment. Extends 17.7mm outwards. Check wheel arch clearance under full suspension compression.

Inner Strut Space:7.7mm LESS clearance

Outer Fender Push:Extends 17.7mm further out

Ride Height Delta:+1.09" ground clearance

Vehicles That Fit 265/45R18 (54+ Models)

Factory standard and optional vehicle fitments utilizing 265/45R18 tires:

Year	Make & Model	Trim / Variant	Lookup Specs
2017	Cadillac CT6	Plug-In	View 2017 CT6 ›
2018	Cadillac CT6	Plug-In	View 2018 CT6 ›
2013	Porsche Boxster	Base, Automatic DCT Trans	View 2013 Boxster ›
2013	Porsche Boxster	Base, Standard Trans	View 2013 Boxster ›
2014	Porsche Boxster	Base, Automatic DCT Trans	View 2014 Boxster ›
2014	Porsche Boxster	Base, Standard Trans	View 2014 Boxster ›
2014	Porsche Cayman	Base, Automatic DCT Trans	View 2014 Cayman ›
2014	Porsche Cayman	Base, Standard Trans	View 2014 Cayman ›
2015	Porsche Boxster	Base, Standard Trans	View 2015 Boxster ›
2015	Porsche Boxster	Base, Automatic DCT Trans	View 2015 Boxster ›
2015	Porsche Cayman	Base, Automatic DCT Trans	View 2015 Cayman ›
2015	Porsche Cayman	Base, Standard Trans	View 2015 Cayman ›
2016	Porsche Boxster	Base, Standard Trans	View 2016 Boxster ›
2016	Porsche Boxster	Base, Automatic DCT Trans	View 2016 Boxster ›
2016	Porsche Cayman	Base, Automatic DCT Trans	View 2016 Cayman ›
2016	Porsche Cayman	Base, Standard Trans	View 2016 Cayman ›
2017	Porsche 718 Boxster	Base, Standard Trans	View 2017 718 Boxster ›
2017	Porsche 718 Boxster	Base, Automatic DCT Trans	View 2017 718 Boxster ›
2017	Porsche 718 Cayman	Base, Standard Trans	View 2017 718 Cayman ›
2017	Porsche 718 Cayman	Base, Automatic DCT Trans	View 2017 718 Cayman ›
2018	Porsche 718 Boxster	Base, Automatic DCT Trans	View 2018 718 Boxster ›
2018	Porsche 718 Boxster	Base, Standard Trans	View 2018 718 Boxster ›
2018	Porsche 718 Cayman	Base, Automatic DCT Trans	View 2018 718 Cayman ›
2018	Porsche 718 Cayman	Base, Standard Trans	View 2018 718 Cayman ›
2019	Porsche 718 Boxster	Base, Automatic DCT Trans	View 2019 718 Boxster ›
2019	Porsche 718 Boxster	Base, Standard Trans	View 2019 718 Boxster ›
2019	Porsche 718 Cayman	Base, Automatic DCT Trans	View 2019 718 Cayman ›
2019	Porsche 718 Cayman	Base, Standard Trans	View 2019 718 Cayman ›
2020	Porsche 718 Boxster	Base, Standard Trans	View 2020 718 Boxster ›
2020	Porsche 718 Boxster	Base, Automatic DCT Trans	View 2020 718 Boxster ›
2020	Porsche 718 Cayman	Base, Standard Trans	View 2020 718 Cayman ›
2020	Porsche 718 Cayman	Base, Automatic DCT Trans	View 2020 718 Cayman ›
2021	Porsche 718 Boxster	Base, Automatic DCT Trans	View 2021 718 Boxster ›
2021	Porsche 718 Cayman	Base, Automatic DCT Trans	View 2021 718 Cayman ›
2021	Porsche 718 Boxster	Base, Standard Trans	View 2021 718 Boxster ›
2021	Porsche 718 Cayman	Base, Standard Trans	View 2021 718 Cayman ›
2022	Porsche 718 Boxster	Base, Automatic DCT Trans	View 2022 718 Boxster ›
2022	Porsche 718 Boxster	Base, Standard Trans	View 2022 718 Boxster ›
2022	Porsche 718 Cayman	Base, Standard Trans	View 2022 718 Cayman ›
2022	Porsche 718 Cayman	Base, Automatic DCT Trans	View 2022 718 Cayman ›
2023	Porsche 718 Boxster	Base, Standard Trans	View 2023 718 Boxster ›
2023	Porsche 718 Boxster	Base, Automatic DCT Trans	View 2023 718 Boxster ›
2023	Porsche 718 Cayman	Base, Automatic DCT Trans	View 2023 718 Cayman ›
2023	Porsche 718 Cayman	Base, Standard Trans	View 2023 718 Cayman ›
2024	Porsche 718 Boxster	Base, Automatic DCT Trans	View 2024 718 Boxster ›
2024	Porsche 718 Boxster	Base, Standard Trans	View 2024 718 Boxster ›
2024	Porsche 718 Cayman	Base, Standard Trans	View 2024 718 Cayman ›
2024	Porsche 718 Cayman	Base, Automatic DCT Trans	View 2024 718 Cayman ›
2025	Porsche 718 Boxster	Base, Standard Trans	View 2025 718 Boxster ›
2025	Porsche 718 Boxster	S, Eng CD MDJ.UB	View 2025 718 Boxster ›
2025	Porsche 718 Boxster	GTS 4.0, Eng CD MDW.AD	View 2025 718 Boxster ›
2025	Porsche 718 Cayman	GT4 RS	View 2025 718 Cayman ›
2025	Porsche 718 Cayman	S, Eng CD MDJ.UA	View 2025 718 Cayman ›
2025	Porsche 718 Cayman	Base, Standard Trans	View 2025 718 Cayman ›