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: 4.7763157 / 5 from 152 reviews.
The Altitude 2.0 Helmet is praised for its lightweight and comfortable design, stylish appearance, vibrant colors, and perfect fit. Customers appreciate its ease of use with the Fidlock® magnetic strap buckle and customizable features.
Review topics: [fit, weight, quality, issues, shipping, strap, looks, price, design, color, style, works, customer service, helmet, vents, altitude 2.0, goggles, light, fidlock, vision, buy, brand, seal, gear].
"Super comfortable, lightweight, can not say more on how much i love this helmet."
"The 509 Altitude 2. 0 is a solid, lightweight helmet that’s super comfortable and fits great. It works nicely with all the goggles i've tried regardless of brand. I even managed to fit a stereo system in with some fidgetting. Amazing all around."
"Thank you 509 for this tribute helmet to Mr. Block! I grew up watching his rally stunts and gymkhana. He was inspiring to my friends and I to go flat out and live life the fullest. This helmet is great and as much as I want to keep it perty. I know Mr. Block would full send it no matter how shiny haha."
"The goggles fog very easy and the opening sits in a bad position on your face, it seems like it should be tilted down further but the goggles press against your nose so the bottom of your vision gets cut off."
"Been rocking 509 gear for years now. Hands down the best helmet and goggle setups."
"Sick helmet and high five for the Ken Block shoutout!"
