Runs small, size up
Lightweight and durable hand-laid carbon fiber construction starting weight at 1,670 grams
Fully-integrated communications system powered by Cardo's proprietary DMC technology providing wireless mesh connectivity with up to 14 other riders
JBL speakers with 509's uniquely designed PSI (Pressurized Sound Isolation) system for passive noise cancellation
Innovative Venturi Venting System pulls moist air out without cold wind coming in Venturi Vents
Easily controllable, active chase light for safety and functionality
Comes standard with Fidlock® easy-open magnetic strap clasp
You're going to LOVE the fit. Try it on and experience our perfect fit. If you don't love it, send it back in new and unused condition within 30 days for an exchange or full refund*. Risk free.
Not sure about your size? Try on at your local dealer!
*Street Helmets are a tighter fit due to cheekpad compression, however, they do pack out over time/use.
How to Measure
When measuring your head, use a cloth tape. Start it just above your eyebrows and circle it around the thickest point in the rear of your head and then reference the size guide below.
Scroll to the right to see more sizes
| Size | US Hat Size | Inches | Centimeters |
| X-Small | 6 5/8 - 6 3/4 | 20 7/8 - 21 1/8 | 53 - 54 |
| Small | 6 7/8 - 7 | 21 5/8 - 21 7/8 | 55 - 56 |
| Medium | 7 1/8 - 7 1/4 | 22 1/2 - 22 5/8 | 57 - 58 |
| Large | 7 3/8 - 7 1/2 | 23 1/4 - 23 1/2 | 59 - 60 |
| X-Large | 7 5/8 - 7 3/4 | 24 - 24 1/4 | 61 - 62 |
| 2X-Large | 8 | 24 3/4 - 25 | 63 - 64 |
| 3X-Large | 8 3/4 | 25 1/4 - 25 3/4 | 64 - 65 |
| 4X-Large | 9 | 26 - 26 1/4 | 66 - 67 |
| Youth Small | 6 | 18 1/8 - 18 7/8 | 47 - 48 |
| Youth Medium | 6 1/8 - 6 1/4 | 19 1/4 - 19 5/8 | 49 - 50 |
| Youth Large | 6 3/8 - 6 1/2 | 20 - 20 1/2 | 51 - 52 |
Pressure Points
When trying on a helmet, take note of any pressure points on your forehead—a sign that the helmet is too round. Pressure points on the sides of your head indicate a helmet is too oval for the shape of your head. After you buy a new helmet, try wearing it for 30 to 45 minutes to check for pressure points before using it on a ride.
Pressure Points
When trying on a helmet, take note of any pressure points on your forehead—a sign that the helmet is too round. Pressure points on the sides of your head indicate a helmet is too oval for the shape of your head. After you buy a new helmet, try wearing it for 30 to 45 minutes to check for pressure points before using it on a ride.
Overall rating: 4.017857 / 5 from 56 reviews.
The Mach V Carbon Commander Helmet is praised for its phenomenal quality, fantastic design, and lightweight construction. Customers appreciate its sleek look and the integrated Cardo system, which outperforms aftermarket add-ons. The helmet also features advanced noise-canceling JBL speakers and air pump ear pads for comfort.
Review topics: ["fit","model","strap","issues","weight","quality","looks","function","design","customer service","technology","works","sound","padding","support","features","helmet","speakers","shield","system","music","visor","cardo","commander","lens","ears","wind","light","picture","rides"].
"Awesome helmet 😁"
"The image doesn't do this justice. This helmet set thr ground for how all futur manufacturers think about including technology with safety. Love the look got so many compliments. Love the cardo integration and speakers and audio quality. Love the no fogging lens. This helmet is great."
"I was very impressed with the clear instruction and delivery of the replacement. The troubleshoot and customer service was very good. I love my helmet and it's working perfect."
"What a great helmet!!! Looks amazing, fits perfect and love the features it offers, the light in the back and the built in Cardo system!!! Fantastic job 509 Team."
"The helmet looks sooo much better in real life, love the flashy rear light and the fact that I can hook it up while I'm using it (I often do 10-12H rides in a day) Fit is great, adjustable earcuffs is a nice touch! I bit on the heavy side, but I have neck pain and I can still wear it all day long!"
"The look of the helmet is amazing fun and modern. The actual function and form … hard pass it’s gone back in the box and sits now the helmet interior design is horrible the ear cups serve. No purpose the fit over all reminds me of a knock off agv . It does look cool but over all function you really fell it on you head when you ride"
"Its been doing great when I first got it, but now it's starting to fall apart on me. The visor making a loud click when i open it, the Bluetooth buttons are starting to malfunction, the bottom front part that secures the visor down somehow broke apart. Isn't tight on my head anymore"
"Helmet weighs more than one would think it should for a carbon helmet. Bought two of these, one of them had a battery failure and had to be replaced. CS handled it well. No snow shield available per CS, seems a little crazy for the price of this helmet that it cant be used in multiple seasons."
"All in all, I believe it's a good helmet. I've only got 2 actual issues with it; my biggest issue is the wind noise. Once you get past 70-ish mph, the noise you're getting from the wind, especially on the highway, is deafening. You can barely make out your music over the wind or hear any words, even when you use the air pump to get the ear muffs tighter around your ears. I can even put my hand over the side of the helmet where my ear is, and the wind noise goes away. My second issue with the helmet is that there really is no real place to mount a GoPro, making it extremely hard for anyone wanting to record daily commutes, forcing us to resort to mounting a camera on our bike."
"When I take long rides this is my go to helmet. Somewhat tight fit but snug is a good thing. Looks fantastic and has excellent fuctions, my ability to listen to music or answer my phone while riding was a must and this helmet takes the cake!"
