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O'Neal  |  SKU: CA-ON0818522

Oneal 2024 Sierra II V.23 Flat Black Helmet

In Stock

Online Only

Ready For Delivery

$209.96 $249.95
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Size

Please note that the following sizing chart is intended to be used as a guide only. We highly recommend trying on the riding gear before purchase to ensure the best fit.

MX HELMETS SIZE CHART (CM) 

10 SRS

Size Head Circumference (cm) Cheek Pad (mm) Weight (kg)
XS 53 - 54 38 1.15 - 1.20
SM 55 - 56 33 1.15 - 1.20
MD 57 - 58 28 1.15 - 1.20
LG 59 - 60 30 1.20 - 1.25
XL 61 - 62 25 1.20 - 1.25
2XL 63 - 64 20 1.20 - 1.25

5 SRS

Size Head Circumference (cm) Cheek Pad (mm) Weight (kg)
XS 53 - 54 38 1.38 - 1.43
SM 55 - 56 33 1.38 - 1.43
MD 57 - 58 28 1.38 - 1.43
LG 59 - 60 30 1.38 - 1.43
XL 61 - 62 25 1.38 - 1.43
2XL 63 - 64 20 1.38 - 1.43
3XL 65 - 66 20 1.38 - 1.43
4XL 67 - 68 20 1.38 - 1.43
5XL 69 - 70 20 1.37 - 1.43

3 SRS

Size Head Circumference (cm) Cheek Pad (mm) Weight (kg)
XS 53 - 54 38 1.35 - 1.40
SM 55 - 56 33 1.35 - 1.40
MD 57 - 58 28 1.35 - 1.40
LG 59 - 60 30 1.35 - 1.40
XL 61 - 62 25 1.35 - 1.40
2XL 63 - 64 20 1.35 - 1.40
3XL 65 - 66 20 1.35 - 1.40

2 SRS

Size Head Circumference (cm) Cheek Pad (mm) Weight (kg)
XS 53 - 54 63 1.45 - 1.50
SM 55 - 56 58 1.45 - 1.50
MD 57 - 58 48 1.45 - 1.50
LG 59 - 60 53 1.45 - 1.50
XL 61 - 62 43 1.45 - 1.50
2XL 63 - 64 38 1.45 - 1.50

1 SRS

Size Head Circumference (cm) Cheek Pad (mm) Weight (kg)
XS 53 - 54 40 1.37 - 1.47
SM 55 - 56 35 1.37 - 1.47
MD 57 - 58 35 1.37 - 1.47
LG 59 - 60 30 1.37 - 1.47
XL 61 - 62 25 1.37 - 1.47

HOW TO MEASURE

Head Circumference

Using a measuring tape, measure the Head Circumference at the head's widest point, just above the eyebrows and ears.

MEN'S JERSEY SIZE CHART (CM) 

Size Chest (cm) Chest (inch)
SM 81.3 - 86.4 32 - 34
MD 88.9 - 94 35 - 37
LG 96.5 - 102 38 - 40
XL 104 - 109 41 - 43
2XL 112 - 117 44 - 46
3XL 119 - 127 47 - 50

MEN'S PANTS SIZE CHART (CM)

Size Waist (cm) Hip (cm) Inseam (cm)
28 76.2 86.4 - 88.9 69.6
30 81.3 91.4 - 94 71.1
32 86.4 96.5 - 99.1 72.4
34 91.4 102 - 104 73.9
36 96.5 107 - 109 75.4
38 102 112 - 114 77
40 107 117 - 119 77
42 112 122 - 124 77
44 117 127 - 130 79
46 122 132 - 135 79
48 127 137 - 140 80
50 132 142 - 145 80
52 137 147 - 150 81

HOW TO MEASURE 

A. Chest

Measure around the fullest part, under the armpits, keeping the tape horizontal.

B. Waist

Measure around the natural waist line, inline with the navel, keeping the tape horizontal.

C. Hip

Measure around the fullest part of your hips, about 20cm below waist line, keeping the tape horizontal.

E. Inseam

Stand against a wall, ask someone else to measure from the crotch to the bottom of your leg.

MEN'S GLOVES SIZE CHART (CM)  

Universal Size Size Length (cm)
XS 7.5 17.5 - 18
SM 8 18 - 18.5
MD 9 18.5 - 19.3
JG 10 19.3 - 20.1
XL 11 20.1 - 20.6
2XL 12 20.6 - 21.1
3XL 13 21.1 - 21.8
4XL 14 21.8 - 22.6
5XL 15 22.6 - 23.1

HOW TO MEASURE

Hand Length

Measure from the tip of the longest finger to the crease under the palm

MEN'S FOOTWEAR CONVERSION 

US UK EU Length (cm)
7 6 39 26.6
7.5 6.5 40 27
8 7 41 27.5
9 8 42 28.3
10 9 43 29.1
10.5 9.5 44 29.6
11 10 45 29.9
12 11 46 30.8
13 12 47 31.7
14 13 48 32.5
15 14 49 33.4

HOW TO MEASURE 

Using a tape measure or ruler, measure the distance from the back of your heel to the end of your longest toe. 

WOMEN'S JERSEY SIZE CHART (CM) 

Size Chest (cm) Chest (inch)
XS 81.3 - 83.8 32 - 33
SM 86.4 - 88.9 34 - 35
MD 91.4 - 94 36 - 37
LG 96.5 - 102 38 - 40
XL 104 - 109 41 - 43

WOMEN'S PANT SIZE CHART (CM) 

US Size Waist (cm) Hip (cm) Inseam (cm)
1/2 58.4 - 61 85.1 - 87.6 65
3/4 63.5 - 66 90.2 - 92.7 66
5/6 68.6 - 71.1 92.7 - 95.3 70.1
7/8 73.7 - 76.2 95.3 - 97.8 71.1
9/10 78.7 - 81.3 97.8 - 102 71.9
11/12 83.8 - 86.4 102 - 105 72.9
13/14 88.9 - 91.4 105 - 109 74.9

HOW TO MEASURE

A. Chest

Measure around the fullest part, under the armpits, keeping the tape horizontal.

B. Waist

Measure around the natural waist line, inline with the navel, keeping the tape horizontal.

C. Hip

Measure around the fullest part of your hips, about 20cm below waist line, keeping the tape horizontal.

E. Inseam

Stand against a wall, ask someone else to measure from the crotch to the bottom of your leg.

WOMEN'S GLOVES SIZE CHART (CM)

Universal Size Size Length (cm)
SM 6 16.8 - 17.5
MD 7 17.5 - 18
JG 8 18 - 18.8
XL 9 18.8 - 19.3
2XL 10 19.3 - 20.1

HOW TO MEASURE

Hand Length

Measure from the tip of the longest finger to the crease under the palm

WOMEN'S FOOTWEAR CONVERSION 

US UK EU Length (cm)
5 3 35 22
6 4 36 23
7 5 37 24
8 6 39 25
9 7 40 26
10 8 41 27
11 9 42 28
12 10 43 29

HOW TO MEASURE 

Using a tape measure or ruler, measure the distance from the back of your heel to the end of your longest toe. 

YOUTH HELMETS SIZE CHART (CM) 

2 SRS YOUTH

Size Head Circumference (cm) Cheek Pad (mm) Weight (kg)
SM 49 - 50 45 1.15 - 1.20
MD 50 - 52 40 1.15 - 1.20
LG 53 - 54 35 1.15 - 1.20

1 SRS YOUTH

Size Head Circumference (cm) Cheek Pad (mm) Weight (kg)
SM 47 - 48 30 1.05 - 1.13
MD 49 - 50 25 1.05 - 1.13
LG 51 - 52 20 1.05 - 1.13
XL 53 - 54 25 1.05 - 1.13

HOW TO MEASURE 

Head Circumference

Using a measuring tape, measure the Head Circumference at the head's widest point, just above the eyebrows and ears. 

YOUTH JERSEY SIZE CHART (CM) 

Size Chest (cm) Chest (inch)
XS 55.9 - 58.4 22 - 23
SM 61 - 63.5 24 - 25
MD 66 - 68.6 26 - 27
LG 71.1 - 73.7 28 - 29
XL 76.2 - 78.7 30 - 31

YOUTH PANT SIZE CHART (CM) 

Age US Size Waist (cm) Hip (cm) Inseam (cm)
2-3 18 45.72 45.7 - 48.3 41
4-5 20 50.8 50.8 - 53.3 46
5-6 22 55.88 55.9 - 58.4 50
8-10 24 60.96 61 - 63.5 55
12-14 26 66.04 66 - 68.6 59
16-18 28 71.12 71.1 - 73.7 63

HOW TO MEASURE

A. Chest

Measure around the fullest part, under the armpits, keeping the tape horizontal.

B. Waist

Measure around the natural waist line, inline with the navel, keeping the tape horizontal.

C. Hip

Measure around the fullest part of your hips, about 20cm below waist line, keeping the tape horizontal.

E. Inseam

Stand against a wall, ask someone else to measure from the crotch to the bottom of your leg.

YOUTH'S GLOVES SIZE CHART (CM) 

Universal Size Size Length (cm)
XS 1/2 13.5 - 13.7
SM 3/4 13.7 - 14.2
MD 5 14.2 - 15
JG 6 15 - 15.5
XL 7 15.5 - 16

HOW TO MEASURE

Hand Length

Measure from the tip of the longest finger to the crease under the palm

YOUTH FOOTWEAR CONVERSION 

US UK EU Length (cm)
11 10 30 19
12 11 31 19.8
13 12 32 20.7
1 13 33 21.5
2 1 34 22.4
3 2 35 23.3
4 3 36 24.1
5 4 37 24.9
6 5 38 25.8

HOW TO MEASURE 

Using a tape measure or ruler, measure the distance from the back of your heel to the end of your longest toe. 

UNDERDOG III BODY PROTECTOR

Size Chest Width (cm) Chest Length (cm) Sleeve Length (cm) Back Length (cm)
SM 88.9 78 74 52.1
MD 93 86 74.9 52.1
LG 97 86 76.2 52.1
XL 101 89.9 77 52.1
2XL 105 94 78 57.1

HOLESHOT CHEST PROTECTOR

Size Chest Width (cm) Chest Length (cm) Back Length (cm)
ONE SIZE 40 39 50

SPLIT CHEST PROTECTOR

Size Chest Width (cm) Front Length (W/O Straps) (cm) Back Length (W/O Straps) (cm)
ONE SIZE 31.8 40.6 41.9

STV SHIRT PROTECTORS

Size Chest Width (cm) Back Length (cm)
SM 81.9 67.9
MD 84 70.5
LG 86 72.5
XL 88 74.5
2XL 90.2 76.5

TRAIL PANT/SHORT

Size Waist (cm)
SM 68.6 - 76.2
MD 78.7 - 83.8
LG 86.4 - 94
XL 96.5 - 102
2XL 104 - 107

DIRT ELBOW GUARD

Size Bicep (cm) Forearm (cm)
MD 31.1 25
LG 33 26.9
XL 34.9 29

FLOW ELBOW GUARD

Size Bicep (cm) Forearm (cm)
MD 29 16.5
LG 30.5 18.5
XL 32 21

KNEE PROTECTION

Size Thigh (cm) Calf (cm)
SM 41.9 34.9
MD 41.9 - 44 34.9 - 36.8
LG 44 - 46 36.8 - 39
XL 46 - 48 39 - 41
2XL 48 - 50 41 - 42

YOUTH UNDERDOG II BODY PROTECTOR

Size Chest Width (cm) Chest Length (cm) Sleeve Length (cm) Back Length (cm)
SM 80 67.9 47 59.9
MD 83.8 71.9 47 62
LG 89.9 76.2 50 64

YOUTH SPLIT CHEST PROTECTOR

Size Chest Width (cm) Front Length (W/O Straps) (cm) Back Length (W/O Straps) (cm)
ONE SIZE 26.7 33 34.9

YOUTH PEEWEE CHEST PROTECTOR

Size Breastplate Width (cm) Breastplate Length (cm) Back Plate Width (cm) Back Plate Length (cm) Sleeve Length (cm)
XS/SM 19.1 22.9 31 22.9 21
MD/LG 20 25 34 24.1 23.5

YOUTH PEEWEE ELBOW PROTECTOR

Size Age
XS/SM 3-5
MD/LG 5-7

YOUTH KNEE GUARDS

Size Age
XS/SM 3-5
MD/LG 5-7

YOUTH DIRT KNEE GUARDS

Size Thigh (cm) Calf (cm)
SM/MD 26 22.9
LG/XL 29.2 26

YOUTH PEEWEE KNEE PROTECTOR

Size Thigh (cm) Calf (cm)
ONE SIZE 27.9 - 33 26 - 32
Size Chart

O'Neal Sierra II Helmet

O'Neal Sierra II Helmet, featuring polycarbonate/ABS construction, is designed for more aggressive adventure riding and varying terrain. The Sierra II Helmet includes an integrated face shield and a shorter peak visor for more diverse functionality.

Features:

  • Polycarbonate/ABS Shell construction
  • Moisture wicking, removable/washable air channeled comfort liner
  • Vent holes for optimal ventilation
  • Integrated face shield
  • Height adjustable helmet shield
  • Padded chin strap with double-s safety lock
  • Meets DOT and ECE 22.05 safety standards

(Part Numbers: CA-ON0818522, CA-ON0818523, CA-ON0818524, CA-ON0818525, CA-ON0818526)


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