Sena Bike Helmet Size Chart

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

2. Watch the video below to see how to measure your head correctly. (If you don’t see a video below, please refresh this page, or you might need to allow this website through your Ad blocker.)

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.

Sena Bike Helmet Size Charts

Sena Smart Road Cycling Helmets

Model S M L
R1 Smart Cycling Helmet 50 – 55cm 55 – 58cm 58 – 62cm
19⅝” – 21¾” 21¾” – 22⅞” 22⅞” – 24½”
R1 Evo Smart Cycling Helmet 50 – 55cm 55 – 58cm 58 – 62cm
19⅝” – 21¾” 21¾” – 22⅞” 22⅞” – 24½”
R2 Smart Cycling Helmet 50 – 55cm 55 – 58cm 58 – 62cm
19⅝” – 21¾” 21¾” – 22⅞” 22⅞” – 24½”
R2 Evo Smart Cycling Helmet 50 – 55cm 55 – 58cm 58 – 62cm
19⅝” – 21¾” 21¾” – 22⅞” 22⅞” – 24½”
RX2 Smart Cycling Helmet 50 – 55cm 55 – 58cm 58 – 62cm
19⅝” – 21¾” 21¾” – 22⅞” 22⅞” – 24½”
C1 Smart Cycling Helmet 54 – 58cm 58 – 61cm
21¼” – 22⅞” 22⅞” – 23¾”

Sena Smart Hybrid Cycling Helmets

Model M L
Rumba Multi-Sport Helmet 54 – 58cm 58 – 62cm
21¼” – 22⅞” 22⅞” – 24½”
X1S Smart Cycling Helmet 55 – 59cm 59 – 63cm
21¾” – 23⅜” 23⅜” – 24¾”

Sena Smart Trail Helmets

Model M L
M1 Mountain Bike Helmet 55 – 59cm 59 – 63cm
21¾” – 23⅜” 23⅜” – 24¾”
M1 Evo Mountain Bike Helmet 55 – 59cm 59 – 63cm
21¾” – 23⅜” 23⅜” – 24¾”