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Mountain Bike Helmet ST 50 - Black

Sale price: 5.500 KD Regular price:
Color: Choose a color
Size: Select a size
Sale price: 5.500 KD Regular price:
Model: 8500051

Product Features

A photo of the Mountain Bike Helmet ST 50 - Black in use

Mountain Bike Helmet ST 50 - Black : This mountain biking helmet has been designed for your first mountain bike rides.

Protect yourself from branches and bumps with the ST 50 helmet. It is easy to position, with two buckles under the ears and one under the chin. What's more, it comes with 15 vents.

User comfort

Put on a well-fitting helmet with foam pads that you can forget you're wearing.


Adjust the helmet using the 2 buckles under the ears and one under the chin.


Breathe: its 15 ventilation holes let air move through.

Product Reviews

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1030 reviews

Mountain Bike Helmet ST 50 - Black
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Good basic entry helmet

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good for the money

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Poor fit and little adjustment

Unfortunately, despite following guides and measuring as advised, the helmet is too big and the adjustment method for this helmet is ineffective. I will need to return when shops reopen and will buy an alternative (from Decathlon online) in the meantime.I hope that delivery charge is still refundable as unable to return until shops reopen. I should have read the translated reviews before purchase as this appears to be a common complaint.



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Light weight

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Mountain bike helmet

It’s light and great value for money it your on a budget this helmet is great fits nice and snug , does the job

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Excellent product

excellent product

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A basic functional.

It is a basic helmet, but the rear screw size adjustment makes it a perfect fit. The finish is a bit sloppy with the plastic sticker top finish unevenly applied. Otherwise it does what is required.

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Good Quality and Valuable Item

very good quality product

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poor quality

Very bad quality. Not recommended

Dear Rengraj,

We are sorry to hear about your disappointment with the Helmet, this helmet is designed for first time Mountain Bike users and for a short duration of time. However if you have any specific concern please share it with us so that we can look into it and do the needful.

For further details on this Helmet please refer to the link on the website for the same.

Thank you


Great product


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Good buildup

This helmet is manufactured with really good and durable quality of material.

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Good fitting.

Good Product.

Very good opinion

Worthy purchase

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Additional Product informations



  • 100% Expanded Polystyrene


  • 100% Polycarbonate

How do you choose your mountain bike helmet size?

To find your helmet size, just measure your head's circumference.1/ Get a tape measure2/ Wrap it 1 cm above the eyebrows and ears. Do not squeeze too tight. The helmet will be just as tight.3/ If the measurement falls between two sizes, opt for the larger size.This mountain bike helmet is available in two sizes:M: 54 - 58cmL: 58 - 62 cm

When should i replace my helmet?

We recommend replacing your helmet in 2 cases:1/ After a fallIn the event of a fall, the material of your helmet 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 useThe foam of your helmet degrades over time. It can deteriorate due to impact, where it is stored, the climate, and its use. We recommend replacing your helmet at least every 5 years

How do i adjust my helmet?

Follow these 2 quick steps to adjust your helmet in 5 minutes:1/ Clip the 2 straps with the buckle: check that you can still slide 2 fingers between the strap and your chin.2/ Adjust the straps so that they form a "Y" on each side of your ears. Just below the ear.The helmet should be in contact with your head, without tipping forward, backward, or sideways, even when you're moving.

Compatible accessories

This helmet is not adapted to attach a headlamp or other lighting source. Do you want to film your rides with a mountable camera? For your safety, we recommend attaching your sport camera directly onto the handlebars or on your torso with a suitable harness.

Combining sport & safety

The helmet can seem restrictive at first. The Rockrider team is unanimous: for mountain biking, helmets have an important role to play.Moreover, we all wear a helmet. For us, helmets are essential. Don't forget to wear one! ;)

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 this product is right for you before buying.If you do need to return it, you will need to make sure it still has its instructions, labels and, where applicable, original packaging. This will enable it to be resold. Together, we can respect our planet.

Additional Recently viewed


Size Guide Visual