Mountain Bike Helmet ST 500 - Red


This well-ventilated, adjustable mountain biking helmet is designed for rides lasting over 2 hours.

The dial makes it easy to adjust while the removable foam on the inside makes it comfortable.Plus they have 17 wide vents, compatible with a ponytail and a rear clip-on light.

Color: Bright red
Size: size guide


Product benefits

User comfort

Forget it's there: its comfortable removable foam pads prevent pressure points.


The 3D tightening dial guarantees a good hold during your rides.

Ease of use

Fixed side straps. Quick and easy to pull your pony tail through.


Air circulates through the 17 vents.


Compatible with a ponytail and a rear clip-on light.

Impact protection

Complies with EN 1078.


Size S: 280 g Size M: 320 g Size L: 370 g

Technical information


17 vents
Chinstrap fastening: clip
Occipital adjustment: 360° dial.
Comfort foam: detachable and washable (available from after-sales)
Visor: fixed, detachable.
Outer shell: polycarbonate Inmold.
Compatibility: ponytail and clip-on light (rear).
Space requirements, size M: Length: 30 cm, width: 21 cm, height: 15.5cm


To find your helmet size, simply measure your head circumference (around the forehead). This mountain bike helmet is available in three sizes:
S: 52 - 55 cm
M : 55 - 59 cm
L: 59 - 62 cm


European standard setting out the requirements and test methods for helmets to be worn by users of rollerblades, skateboards, scooters and bicycles. The corresponding requirements and test methods cover the following aspects: construction, including field of vision; shock absorption properties; characteristics of the retention system, including the chinstrap and tightening devices; marking and information.


A cushioning foam replacement kit is available for this helmet on our website

Please note that on some helmets, the colour of the EVA cushioning foams (those in contact with the top of the head) may vary.


We recommend replacing your helmet in 2 cases:

1/ After a fall:
In the event of a fall, your helmet's material can deteriorate or even break. Sometimes, you won't even notice. That is why we recommend replacing it if you have the slightest doubt.

2/After 5 years of use:
The foam deteriorates. It can deteriorate due to impact, where it is stored, the climate, and its use. We therefore recommend replacing your helmet at least every 5 years.


3 quick steps for adjusting your helmet in 2 minutes:
1/ If needed, pull your ponytail through the back of the helmet (lower the dial's rim).

2/ Adjust and clip the buckles on the 2 straps: check that you can still slide 2 fingers between the strap and your chin.

3/ Adjust the tightness around your head using the rear dial.

The helmet should be in contact with your head, without tipping forward, backward, or sideways, even when you're moving.

Product tests

Our team of product designers based at the B'Twin Village in Lille is continuously working to make cycling more comfortable for our users.
Our obsession is to create products that meet the specific cycling needs of our users and eliminate things that get in the way of their rides.

A rating to compare products' environmental impact.

A product's environmental impact is calculated for its entire life cycle using various indicators.
An overall rating (ABCDE) is given, allowing you to easily identify products with the best environmental performance by comparing similar products to each other (T-shirts, trousers, backpacks etc.).

Decathlon openly displays the environmental ratings of its products.
To find out more:

Returns conditions for personal protective equipment

Make sure that this product fits properly.

If you do need to return it, you will need to make sure it still has its instructions, labels and, where applicable, original packaging. so that it can be reconditioned. Let's take care of our planet, together.


2 years

Product concept & technology

Product Composition

Foam 100% Expanded Polypropylene Shell 100% Polycarbonate Buckles 100% Polyoxymethylene Webbing 100% Polyester


Store the helmet in a dry place away from direct sunlight, and avoid high temperatures (> 60°C).
Clean the outside with a simple soft sponge and neutral soap.

User Directions

Suitable for skating & skateboarding. Not for motor sports.


Our engineers always have real riders test all our products in real conditions. These tests round out our lab tests and let us validate all our products before they hit store shelves.A helmet is a piece of safety equipment: for this reason, we perform numerous tests on it, in particular, those required by safety regulations. This helmet complies with EN 1078 standard for cycling, skating and skateboarding helmets.


Mountain Bike Helmet ST 500 - Red
Mountain Bike Helmet ST 500 - Red
Mountain Bike Helmet ST 500 - Red
Mountain Bike Helmet ST 500 - Red
Mountain Bike Helmet ST 500 - Red
Mountain Bike Helmet ST 500 - Red
Mountain Bike Helmet ST 500 - Red
Mountain Bike Helmet ST 500 - Red


Customer reviews