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ST 100 Mountain Bike Helmet -
ST 100 Mountain Biking Helmet - Red
  • ST 100 Mountain Biking Helmet - Red
  • ST 100 Mountain Biking Helmet - Red
  • ST 100 Mountain Biking Helmet - Red
  • ST 100 Mountain Biking Helmet - Red
  • ST 100 Mountain Biking Helmet - Red
  • ST 100 Mountain Biking Helmet - Red
  • ST 100 Mountain Biking Helmet - Red

ST 100 Mountain Bike Helmet -

536 of 560 people recommends this product
Our team has designed this mountain bike helmet for protecting you from branches and impacts on your first mountain bike rides (up to 1½ hours).
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        User comfort

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


        Adjust the helmet to your head using the adjustment wheel.


        Breathe: its 9 large ventilation holes let air move through.

        Easy to use

        Enjoy: Y-shaped straps stitched under the ears for a snug fit.



        To figure out your helmet size, you need to measure your head. 1/ Get a tape measure 2/ Place it around your head, about 1 cm above your eyebrows and ears. Do not pull too tight. You will be able to tighten your helmet. 3/ If you are between sizes, choose the larger size. This mountain bike helmet is available in two sizes: M: 53 - 57 cm L: 57 - 62 cm Please note: for safety reasons, helmets cannot be returned.


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


        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/ Lastly, adjust the tightness around your head. The helmet should be in contact with your head, without tipping forward, backward, or sideways, even when you're moving.


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


        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! ;)


        4.5/5 560 reviews
        536 of 560 people recommends this product
        Post a review
        Mauvaise qualité
        Used for 2 to 8 weeks
        Produit retourné et échangé contre un casque de gamme supérieure
        Response of the brand
        Bonjour Monsieur,

        Je vous remercie pour votre avis concernant noter casque VTT ST 100.
        Je suis content de lire que notre politique d'échange vous a permis de trouver le produit approprié à votre usage.
        Je serais intéressé de connaitre les raisons précises qui vous ont motivé à monter en gamme.
        Vous pouvez m'adresser vos problématiques directement par mail à l'adresse
        Je vous remercie par avance pour le temps que vous voudrez bien accorder à la question.

        Sylvain _ Chef de Produit
        Guy found this answer helpful
        Rock rider Helmet
        Used for 7 to 12 months
        I was given a new helmet, Rock rider ST100 White for my birthday last August 2018. Within 24 hours the ratchet adjuster had given up and I was reluctantly given a replacement after complaining at the store, finally it was deemed to be a manufacturing fault. The adjuster on this one has just given up on me (April 2019), it is too dangerous to use as it does not stay in place on the head.
        Response of the brand
        I'm sorry to read that there was an issue with your helmet. Please return it to us for a refund or a replacement as it's important you have a well fitted helmet for you rides.
        Peter, Cycling Manager, DECATHLON
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