The A3 helmet from Troy Lee Designs isn’t just a piece of kit — it’s a revolution in safety and comfort.
Built for ambitious cyclists who refuse to compromise, it combines cutting-edge protection technology with unrivalled lightness.
Thanks to 16 intelligently positioned ventilation ports, the helmet practically disappears on your head, while its advanced construction protects you like never before. A feeling of safety without the feeling of weight — that’s the A3 promise.
- Maximum protection with Mips® B-Series technology
Your brain is protected against rotational impacts by one of the most advanced systems on the market, significantly reducing the risk of injury in a crash. - Incredible lightness — just 315 grams
So light you’ll barely notice it, yet it delivers the professional level of protection you need.
- In-moulded EPP and EPS construction
- 16 optimally tuned ventilation ports
- Advanced three-piece shell
- Sweat Glide system — moisture-wicking EVA foam
- 3D magnetic Fidlock® system
- Smart visors with automatic release
Specifications:
Weight: 315 g
Visor: 3-Way Magnajust®
Inner liner: 2-piece Ionic®
Certification: CPSC 1203, CE EN 1078, AS NZ 2063:2008*
Note: Certifications vary by regional standards
What started as a hobby for motocross racer Troy Lee, painting helmets for his friends in his parents' garage, has grown to become recognized as the premier helmet painting competition in the world. Troy Lee Designs supplies motocross and mountain bike equipment to the world's fastest racers.
Helmets – head circumference (cm)
These measurements may vary slightly from model to model.
| Model | YOUTH | XS | XS/S | SM | MD | LG | XL | Extra Large / Extra Extra Large | 2X |
| D4 | – | 53–54 | – | 55–56 | 57–58 | 58–59 | 60–61 | – | 62–63 |
| D3 | – | 53 | – | 54–55 | 56–57 | 58–59 | 60–62 | – | 63–65 |
| A3 / Stage | – | – | 53–56 | – | – | – | – | 60–63 | – |
| Flowline / Flowline SE / Grail | 48–53 | – | 53–56 | – | – | – | – | 60–63 | – |
A3 / Stage a Flowline: M/L = 57–59 cm.
Men's jerseys
| Size | SM | MD | LG | XL | XXL |
| Center of the front from the shoulder (cm) | 69,9 | 71,8 | 73,7 | 75,6 | 77,5 |
| Center of the back from the shoulder (cm) | 76,2 | 78,1 | 80,0 | 81,9 | 81,9 |
| Bust measurement (cm) | 50,8 | 54,6 | 58,4 | 62,2 | 67,3 |
| Waist size (cm) | 50,2 | 54,0 | 57,8 | 61,6 | 66,7 |
| Sleeve opening (cm) | 9,5 | 10,2 | 10,8 | 11,4 | 12,1 |
| Length of long sleeve from the center of the neck (cm) | 85,1 | 87,6 | 90,2 | 92,7 | 95,3 |
Men's shorts / pants
| Size | 28 | 30 | 32 | 34 | 36 | 38 | 40 |
| Waist size (cm) | 37,5 | 40,0 | 42,5 | 45,1 | 47,6 | 50,2 | 52,7 |
| Length across the hips (cm) | 48,3 | 50,8 | 53,3 | 55,9 | 58,4 | 61,0 | 63,5 |
| Inseam (cm) | 32,4 | 33,7 | 34,9 | 36,2 | 37,5 | 38,7 | 40,0 |
| Leg opening (cm) | 14,0 | 14,6 | 15,2 | 15,9 | 16,5 | 17,1 | 17,8 |
| Inseam – pants (cm) | 80,0 | 82,6 | 82,6 | 82,6 | 85,1 | 85,1 | 85,1 |
Women's jerseys
| Size | XS | S | M | L | XL |
| Center of the front from the shoulder (cm) | 59,7 | 62,2 | 63,5 | 65,4 | 66,7 |
| Center of the back from the shoulder (cm) | 67,3 | 69,2 | 71,1 | 73,0 | 74,3 |
| Bust measurement (cm) | 40,0 | 43,8 | 47,6 | 51,4 | 55,2 |
| Waist size (cm) | 37,5 | 41,3 | 45,1 | 48,9 | 52,7 |
| Short sleeve length from the center of the neck (cm) | 11,4 | 13,3 | 15,2 | 17,1 | 19,1 |
Women's shorts / pants
| Size | XS | SM | MD | LG | XL |
| Waist size (cm) | 37,5 | 40,0 | 42,5 | 45,1 | 47,6 |
| Length across the hips (cm) | 47,6 | 50,2 | 52,7 | 55,2 | 57,8 |
| Inseam (cm) | 30,5 | 31,8 | 33,0 | 34,3 | 35,6 |
| Leg opening (cm) | 21,6 | 22,9 | 24,1 | 25,4 | 26,7 |
| Inseam – shorts (cm) | 49,5 | 51,4 | 53,3 | 55,2 | 55,2 |
Kids' jerseys
| Size | XS | SM | MD | LG | LX |
| Center of the front from the shoulder (cm) | 49,5 | 52,1 | 54,6 | 57,1 | 59,7 |
| Center of the back from the shoulder (cm) | 54,6 | 57,1 | 59,7 | 62,2 | 64,8 |
| Chest circumference (cm) | 35,6 | 38,1 | 40,6 | 43,2 | 45,7 |
| Waist size (cm) | 35,6 | 38,1 | 40,6 | 43,2 | 45,7 |
| Sleeve opening (cm) | 6,99 | 7,62 | 8,26 | 8,89 | 9,53 |
| Sleeve length (cm) | 61 | 63,5 | 66 | 68,6 | 71,1 |
Kids' shorts / pants
| Size | 28 | 30 | 32 | 34 | 36 | 38 | 40 |
| Waist size (cm) | 74,9 | 80 | 85,1 | 90,2 | 95,3 | 100 | 105 |
| Length across the hips (cm) | 88,9 | 94 | 99,1 | 104 | 109 | 114 | 119 |
| Inseam (cm) | 64,1 | 66,7 | 69,2 | 71,8 | 74,3 | 76,8 | 79,4 |
| Leg opening (cm) | 48,3 | 50,2 | 52,1 | 54,0 | 55,9 | 57,8 | 59,7 |
| Inseam – pants (cm) | 30,5 | 33 | 33 | 33 | 35,6 | 35,6 | 35,6 |
| Outer seam – pants (cm) | 53,7 | 57,1 | 58,4 | 59,4 | 63,2 | 64,5 | 65,4 |
Protective gear – adults
Knees: Measure 10 cm above the center of the knee (thigh) and 15 cm below the center of the knee (calf). Elbows: Measure the circumference of the wrist behind the wrist bone and above the bicep at its narrowest point. Chest: Measure approximately 2.5 cm below the armpit.
| Typ | Rate | XS/SM | M/L | Extra Large / Extra Extra Large |
| Knee | Lower thigh (cm) | 34,5–39,5 | 39,5–44,5 | 44,5–49,5 |
| Calf (cm) | 32–37 | 37–42 | 42–47 | |
| Weight (kg) | 32–63 | 63–82 | 82–100 | |
| Elbow | Wrist (cm) | 15–17,5 | 17,5–20 | 20–22,5 |
| Upper biceps (cm) | 25,5–30,5 | 30,5–35,5 | 35,5–40,5 | |
| Weight (kg) | 32–63 | 63–82 | 82–100 | |
| Thoracic | Chest (cm) | 86–89 (S) | 91–97 (M) / 102–107 (L) | 112–117 (XL) |
Protective gear – children
The same measurement instructions as for adults. Chest: Measure approximately 2.5 cm below the armpit.
| Typ | Rate | YM | YL |
| Knee | Thigh circumference (cm) | 26,5–30,5 | 30,5–34,5 |
| Calf circumference (cm) | 24–28 | 28–32 | |
| Elbow | Wrist (cm) | 15–17,5 | 17,5–20 |
| Upper biceps (cm) | 17,8–22,9 | 22,9–27,9 | |
| Thoracic | Chest (cm) | 66–68.5 (M) | 71–73.5 (L) / 76–81.5 (XL) |
Gloves
| Group | Size | Hand circumference (cm) | Palm length (cm) |
| Men's | XS | 19–20 | 17,7–18,5 |
| S | 20–21 | 18,5–19 | |
| M | 21–21,7 | 19–19,7 | |
| L | 21,7–22,7 | 19,7–20,3 | |
| XL | 22,7–22,5 | 20,3–20,7 | |
| Women's | XS | 16,5–17,5 | 16–17 |
| S | 17,5–18,2 | 17–17,7 | |
| M | 18,2–19 | 17,7–18,3 | |
| L | 19–19,7 | 18,3–19 | |
| Children's | XXS | 13,6 | 15,1 |
| XS | 14,4 | 15,8 | |
| S | 15,2 | 16,5 | |
| M | 16,0 | 17,2 | |
| L | 16,8 | 17,9 | |
| XL | 17,6 | 18,6 |






