Helmet Sizing Guide
Orthrus (OTS) Helmet Sizing Guide
Getting the right helmet size is critical for both safety and comfort. A helmet that is too loose will not protect you properly in an accident, and a helmet that is too tight will be uncomfortable to ride in.
Follow this guide to find your perfect fit for Orthrus (OTS) Foxhound, Doberman, Husky and all other series helmets.
1. How to Measure Your Head
You will need a soft cloth tape measure. If you don't have one, use a piece of string and then measure the string with a ruler.
-
Placement: Wrap the tape measure around your head about 1 inch (2.5 cm) above your eyebrows and ears. This is usually the widest part of your head.
-
Take the Measurement: Pull the tape comfortable—not too tight, not too loose.
-
Repeat: Measure 2 or 3 times to be sure you have the largest measurement.
2. Adult Size Chart (Foxhound & Doberman Series)
Applicable for all Adult Full Face and Modular helmets.
| Size | Head Circumference (CM) | Head Circumference (INCH) | Hat Size (Approx) |
| Small (S) | 55 - 56 cm | 21.7" - 22.0" | 6 ⅞ - 7 |
| Medium (M) | 57 - 58 cm | 22.4" - 22.8" | 7 ⅛ - 7 ¼ |
| Large (L) | 59 - 60 cm | 23.2" - 23.6" | 7 ⅜ - 7 ½ |
| X-Large (XL) | 61 - 62 cm | 24.0" - 24.4" | 7 ⅝ - 7 ¾ |
| XX-Large (2XL) | 63 - 64 cm | 24.8" - 25.2" | 7 ⅞ - 8 |
📝 Pro Tip: If your measurement falls between two sizes, we recommend choosing the LARGER size for a more comfortable fit, or the SMALLER size if you prefer a tight, professional race fit.
3. Youth Size Chart (Husky Off-Road Series)
For kids and young riders using the Husky AH609 series.
| Youth Size | Head Circumference (CM) | Head Circumference (INCH) |
| Small (S) | 49 - 50 cm | 19.3" - 19.7" |
| Medium (M) | 51 - 52 cm | 20.1" - 20.5" |
| Large (L) | 53 - 54 cm | 20.9" - 21.3" |
| X-Large (XL) | 55 - 56 cm | 21.7" - 22.1" |
4. The "Fit Check": How Should It Feel?
Many new riders think their helmet is "too small" when they first put it on. Here is how to check if it is actually the right size:
-
The Cheek Test: When the chin strap is fastened, the cheek pads should press firmly against your cheeks. You should feel like a "chipmunk." This is normal and ensures the helmet won't rotate during a crash.
-
The Forehead Test: The helmet should fit snugly against your forehead but should not cause pain. If you feel a sharp pressure point on your forehead leaving a red mark after minutes, it is too small.
-
The Shake Test: Shake your head from side to side. The helmet should move with your skin, not slide over your skin. If it slides freely, it is too large.
-
Break-In Period: Keep in mind that the interior padding will compress by about 10-15% after the first 10-20 hours of riding. A brand-new helmet should feel slightly tight.
Still Unsure?
If you have any questions about sizing, please contact our support team at customerservice@otsmoto.com or use the chat button. We are based in Chino, CA and happy to help you find the right Orthrus (OTS) helmet!