jSimpson Race Products has been building race-proven safety gear for decades—but let’s be honest: Sizing charts can trip people up, even those who’ve been around race gear for years, especially when you’re dropping real money on helmets, suits, and gloves.
This guide breaks sizing charts down in a way that actually makes sense—no lab coat required. Whether you’re a garage-built weekend racer, a track-day regular, or someone who wants top-tier gear that fits right the first time, this one’s for you.
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Why Sizing Charts Matter More Than You Think
When it comes to racing gear, sizing isn’t about comfort alone—it’s about function and safety.
- A helmet that’s too loose can move when it shouldn’t.
- A suit that’s too tight can restrict movement.
- Gloves that don’t fit kill feel and control.
Simpson sizing charts aren’t guesses—they’re built around how the gear is designed to protect you. Once you know how to use them, buying gear becomes a lot less stressful.
Pro tip:
- Ignore your T-shirt or jacket size. Measure your body and trust the numbers.
- Tables narrow things down—but they’re not the whole story.
How to Measure Without Overthinking It
- Use a soft measuring tape
- Measure against your body, not over bulky clothes
- Snug, not tight—don’t crank the tape
- Measure twice (seriously)
If you’re between numbers, always go with the larger measurement—then let fit guidance decide the rest.
Helmets
- Should feel snug everywhere
- Cheek pressure is normal
- No rocking or shifting
- Padding will break in slightly
If you’re between sizes: size down for race use
Helmet Sizing Charts:
Adult
|
Size |
Hat Size |
Inches* |
Centimeters |
|
X-Small |
6 ⅝ - 6 ¾ |
20 ½ - 21 ¼ in |
52-54 cm |
|
Small |
6 ⅞ - 7 |
21 ¼ - 22 in |
54-56 cm |
|
Medium |
7 ⅛ - 7 ¼ |
22 - 22 ¾ in |
56-58 cm |
|
Large |
7 ⅜ - 7 ½ |
22 ¾ - 23 ½ in |
58-60 cm |
|
X-Large |
7 ⅝ - 7 ¾ |
23 ½ - 24 ½ in |
60-62 cm |
|
XX-Large |
7 ⅞ - 8 |
24 ½ - 25 ¼ in |
62-64 cm |
* approximate
Youth
|
Size |
Inches* |
Centimeters |
|
Youth Medium |
20 - 20 ½ in |
51-52 cm |
|
Youth Large |
20 ½ - 20 ¾ in |
52-53 cm |
|
Adult Junior |
20 ¾ - 21 ¼ in |
53-54 cm |
* approximate
Stilo Helmet
|
Size |
Hat Size |
Inches* |
Centimeters |
Shell Size |
|
X-Small |
6 ⅝ - 6 ¾ |
21 - 21 ¼ in |
54 cm |
Small shell |
|
Small |
6 ⅞ - 7 |
21 ⅝ - 22 in |
55 cm |
Small shell |
|
Medium |
7 ⅛ - 7 ¼ |
22 ¼ - 22 ¾ in |
57 cm |
Small shell |
|
Large |
7 ¼ - 7 ½ |
23 ¼ - 23 ⅝ in |
59 cm |
Small shell |
|
Large Plus |
7 ¼ - 7 ½ |
23 ¼ - 23 ⅝ in |
60 cm |
Large shell |
|
X-Large |
7 ⅝ - 7 ¾ |
24 - 24 ⅜ in |
61 cm |
Large shell |
|
XX-Large |
7 ⅝ - 7 ¾ |
24 - 24 ⅜ in |
63 cm |
Large shell |
|
XXX-Large |
7 ⅝ - 7 ¾ |
24 - 24 ⅜ in |
64 cm |
Large shell |
* approximate
Stilo CMR Child Karting Helmet
|
Size |
Hat Size |
Inches* |
Centimeters |
Shell Size |
|
X-Small |
6 ⅝ - 6 ¾ |
21 - 21 ¼ in |
54 cm |
VB shell |
|
Small |
6 ⅞ - 7 |
21 ⅝ - 22 in |
55 cm |
VB shell |
|
Small Plus |
7 ⅛ - 7 ¼ |
22 - 22 ¼ in |
56 cm |
VB shell |
|
Medium |
7 ¼ - 7 ½ |
22 ¼ - 2 ¾ in |
57 cm |
Small shell |
|
Large |
7 ¼ - 7 ½ |
23 ¼ - 23 ⅝ in |
59 cm |
Small shell |
* approximate
** Stilo helmets tend to run a bit small. You may want to try one cm larger size than usual. Size Small Plus 56cm available only in CMR helmet.
Racing Suits
- You should be able to sit, bend, and reach comfortably
- Slight looseness is okay
- Excess fabric is not your friend
Height and weight matter just as much as chest size
Racing Suit Sizing Charts
Adult
|
Size (in) |
Chest |
Waist |
Hip |
Inseam |
Neck |
Height |
Weight |
|
Small |
30-34 |
26-30 |
33-37 |
31 |
14.5 |
5’5”-5’7” |
115-130lb |
|
Medium |
34-38 |
30-34 |
37-41 |
32 |
15.5 |
5’7”-5’10” |
140-165lb |
|
Large |
38-42 |
34-38 |
41-45 |
33 |
16.5 |
5’10”-6’2” |
175-200lb |
|
X-Large |
42-46 |
38-42 |
45-49 |
34 |
17.5 |
5’11” & up |
210-225lb |
|
XX-Large |
46-50 |
42-46 |
45-49 |
35 |
18.5 |
5’11” & up |
235-250lb |
Youth
|
Size (in) |
Chest |
Waist |
Hip |
Inseam |
Neck |
Height |
Weight |
|
X-Small |
28-31 |
21-24 |
26-29 |
22 |
11 |
4’0”-4’4” |
50-60lb |
|
Small |
31-33 |
24-26 |
29-31 |
23 |
12 |
4’1”-4’5” |
60-75lb |
|
Medium |
33-36 |
26-28 |
31-33 |
24 |
13 |
4’5”-4’10” |
75-90lb |
|
Large |
36-38 |
29-31 |
34-36 |
26 |
13 |
5’0”-5’4” |
90-105lb |
|
XX-Large |
39-41 |
32-34 |
38-40 |
28 |
14 |
5’4”-5’6” |
105-120lb |
Gloves
- Snug in the palm
- Fingers should reach the ends without bunching
- Control beats comfort every time
Gloves should feel tight at first—not sloppy
Gloves Size Chart
|
Size |
Inches |
Centimeters* |
|
XX-Small |
5-6 in |
12 ½ - 15 ¼ cm |
|
X-Small |
6-7 in |
15 ¼ - 17 ¾ cm |
|
Small |
7-8 ½ in |
17 ¾ - 21 ½ cm |
|
Medium |
8-9 ½ in |
20 ¼ - 24 ¼ cm |
|
Large |
9-10 ½ in |
22 ¾ - 26 ¾1 cm |
|
X-Large |
10-11 ½ in |
25 ½ - 29 ¼ cm |
* approximate
Head & Neck Devices - HANS® and Hybrid
- The device should sit flat on your shoulders, not floating or digging in
- It should feel secure once belted in, not loose or sloppy
- When paired with your helmet and tethers, everything should move together as one system
If it feels awkward outside the car but locks in once you’re strapped down—that’s normal.
Key measurements that matter
- Neck size / collar size (not your shirt size)
- Helmet size and type
- Seat angle (this affects which HANS model you need)
- Harness type and mounting angle
This is one area where guessing or “close enough” isn’t good enough.
Common mistakes to avoid
- Sizing up “for comfort”
- Mixing incompatible helmet anchors or tethers
- Ignoring seat angle recommendations
- Assuming one size fits all across different vehicles
A properly sized head and neck device should disappear once you’re driving—no distraction, no fighting it, just confidence.
Bottom line
Head and neck restraints aren’t comfort gear—they’re life-saving systems. If the chart puts you between sizes, follow the manufacturer’s guidance and prioritize correct geometry over feel in the pits. When everything is sized and set up right, the device does exactly what it’s supposed to do when it matters most.
If you’re ever unsure, this is one category where asking questions is smart—not cautious.
Hybrid Head and Neck Restraints Size Chart
|
Size |
Inches |
Centimeters |
|
Child* |
22-26 in |
56-66 cm |
|
Youth* |
26-30 in |
66-76 cm |
|
X-Small |
32-36 in |
81-91 cm |
|
Small |
36-40 in |
91-102 cm |
|
Medium |
40-44 in |
102-112 cm |
|
Large |
44-48 in |
112-122 cm |
|
X-Large |
48-52 in |
122-132 cm |
* Child and youth sizes available in Hybrid Sport
HANS Device Head and Neck Restraints Size Chart
|
Size |
Inches |
Centimeters* |
|
Super Small |
11-13 in |
28-33 cm |
|
Youth |
13-14 in |
33-35.5 cm |
|
Small |
13-15 in |
33-38 cm |
|
Medium |
15-17 in |
38-43 cm |
|
Large |
17-20 in |
43-51 cm |
* approximate
Race Fit vs “Comfort Fit” (This Is Where People Mess Up)
Here’s the thing: racing gear isn’t supposed to feel like street clothes.
- Race Fit = snug, secure, minimal movement
- Casual Fit = looser, more forgiving
Simpson designs their gear for race fit. Sizing up for comfort often means less protection and worse performance.
If you want the gear to work the way it’s designed to—trust the race fit.
Final Thoughts: Buy Once, Cry Once
Sizing charts don’t have to be complicated. When you:
- Measure correctly
- Use the diagrams
- Understand how the gear is meant to fit
You’re not guessing—you’re dialing it in.
Simpson sizing charts are built around real-world racing, not fashion sizing. Take five extra minutes to measure properly and you’ll end up with gear that fits better, feels right, and does what it’s supposed to do when it matters.
If you ever need a second opinion, that’s what shops like JS Speedshop are here for—because good gear deserves a good fit.
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