Flowline is proof that good protection doesn’t have to be complicated or expensive. This modern Troy Lee Designs helmet hides top-tier safety technology and incredible comfort beneath its minimalist design. Whether you’re riding a mountain trail or relaxing after training, Flowline gives you protection you’ll appreciate — without any unnecessary fuss. Thanks to the innovative Mips® B-Series system and a four-star safety rating from Virginia Tech, you can be confident your head is in the best hands.
- The lightest protection with maximum comfort
Weighing just 375 grams, Flowline gives you protection without the burden — you’ll simply forget you’re wearing it. - Safety to top standards
The Mips® B-Series system and the four-star Virginia Tech rating mean reliable protection in rotational impacts.
- 14 ventilation openings for optimal cooling
- 360° adjustable screwless visor
- Extended coverage suitable for MTB trails
- Fully integrated In-Mould construction
- 3-level rear height adjustment
- Side strap adjusters
Specifications:
Weight: 375 gSafety rating: 4 stars (Virginia Tech)
Construction type: fully integrated In-Mould
Number of vents: 14
Fit system: 360° with 3-level height adjustment
Helmet type: MTB trail helmet with extended coverage
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 |






