Smith Optics 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.
Smith Optics Bike Helmet Size Charts
| Model | XS / Youth S | Small | Medium | Large | Extra Large |
|---|---|---|---|---|---|
| Convoy MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | 61 – 65cm | |
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | 24⅞” – 26⅜” | ||
| Engage MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | 61 – 65cm | |
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | 24⅞” – 26⅜” | ||
| Express & Express MIPS |
51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Forefront 2 MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Ignite MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Jetstream TT MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Mainline MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Maze | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Network MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Persist MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | 61 – 65cm | |
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | 24⅞” – 26⅜” | ||
| Podium TT MIPS | 55 – 59cm | 59 – 62cm | |||
| 21¾” – 23¼” | 23¼” – 24½” | ||||
| Portal MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Route MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Rover MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Session MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Signal MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | 61 – 65cm | |
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | 24⅞” – 26⅜” | ||
| Trace MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Venture MIPS | 51 – 55cm | 55 – 59cm | 59 – 62cm | ||
| 20⅛” – 21⅝” | 21¾” – 23¼” | 23¼” – 24½” | |||
| Wilder Jr. MIPS | 48 – 52cm | ||||
| 18⅞” – 20½” | |||||
| Zip Jr. MIPS | 48 – 52cm | ||||
| 18⅞” – 20½” |
