1. Achieve the perfect fit by measuring your head circumference correctly.

2. Watch the video below to see how to measure your head correctly.

3. VIDEO: How To Measure For A Bike Helmet

4. On the chart below, find the helmet model that you are interested in, then find your head measurement to see which size you need.

Rudy Project Bike Helmet Size Charts

Model	Small	Small/Medium	Large
Airstorm Outlet		54.9 – 58.7cm	59.6 – 61.5cm
Airstorm Outlet		21⅝” – 23⅛”	23½” – 24¼”
Boost 01		54.9 – 58.7cm	59.6 – 61.5cm
Boost 01		21⅝” – 23⅛”	23½” – 24¼”
Protera Outlet		54.9 – 58.7cm	59.6 – 61.5cm
Protera Outlet		21⅝” – 23⅛”	23½” – 24¼”
Protera+		54.9 – 58.7cm	59.6 – 61.5cm
Protera+		21⅝” – 23⅛”	23½” – 24¼”
Racemaster MIPS		54.9 – 58.7cm	59.6 – 61.5cm
Racemaster MIPS		21⅝” – 23⅛”	23½” – 24¼”
Spectrum	51.1 – 54.9cm	55.8 – 58.7cm	59.6 – 61.5cm
Spectrum	20⅛” – 21⅝”	22″ – 23⅛”	23½” – 24¼”
Strym		54.9 – 58.7cm	59.6 – 61.5cm
Strym		21⅝” – 23⅛”	23½” – 24¼”
The Wing		54.9 – 58.7cm	59.6 – 61.5cm
The Wing		21⅝” – 23⅛”	23½” – 24¼”
Volantis		54.9 – 58.7cm	59.6 – 60.6cm
Volantis		21⅝” – 23⅛”	23½” – 23⅞”

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