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Rockrider ST900, Mountain Bike Shorts, Men's

Sale price: $30.00 Regular price: $49.99

These ST 900 shorts are durable and thick to withstand vegetation. The stretch fabric provides freedom of movement. 2 flat secure pockets. The little extra: 2 adjustment rip-tabs at the waist.

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Sale price: $30.00 Regular price: $49.99

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San Francisco, 735 Market St. Options

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Model: 8381758

Product Features

A photo of the Rockrider ST900, Mountain Bike Shorts, Men's in use

Rockrider ST900, Mountain Bike Shorts, Men's | These mountain biking shorts are resistant to vegetation and are designed for rides lasting over 3 hours. Undershorts sold separately.

These ST 900 shorts are durable and thick to withstand vegetation. The stretch fabric provides freedom of movement. 2 flat secure pockets. The little extra: 2 adjustment rip-tabs at the waist.

Abrasion resistant

Sturdy and thick to withstand snags from vegetation.

Freedom of movement

Made from stretchy fabric, with 2 rip-tabs on the waistband to adjust the size.


2 flat zip-up pockets for keeping your belongings secure (such as keys).


The fabric and loose fit wick away perspiration.

Product Lifestyle Image Gallery

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Rockrider ST900, Mountain Bike Shorts, Men's,black 

Rockrider ST900, Mountain Bike Shorts, Men's,black 

Rockrider ST900, Mountain Bike Shorts, Men's,black

Product Customer Reviews

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Rockrider ST900, Mountain Bike Shorts, Men's,black
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Awesome! Comfortable and not baggy! But I took one size smaller. Check sizes

Waist Band Clip Cheap and basically useless

The clip at the top of the fly on the waist band, is very cheap and bends easily, to the point of being almost useless after only being worn twice.. A simple button structure would have been better. The bike shorts themselves are good and comfortable.

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Thank you for taking the time to give us some valuable feedback Colin! I will pass this feedback on to the relevant people! In the mean time if you would like to change your pair for another product feel free to contact the store to organise a refund or exchange!

Great shorts. Great price.

Amazing quality and fit at a great price.

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Mountain bike shorts

Very comfortable and great price

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ST 900 Mountain bike shorts

Top shorts. Stylish and sturdy. Super comfortable.

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Bike shorts ST 900

The shorts fit well and are very comfortable. I shall be buying another pair soon.

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Nice fit

Comfortable fit. Perfect for riding and less conspicuous at coffee stops. Front tab does flare out a bit which is a bit annoying. Similar to stock photo.

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So good I bought 2 more

As described. Very comfortable and great wear.

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Great quality and super confortable

I ve been using them witouth any issueas since day one, super cofortable

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Best quality for not a sky high price

Awesome quality. I used it regularly on trails. I already bought 2 types of mountain bike shorts. I will definitely buy more if there’s new styles coming.

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Decent quality, a little too short for me.

Solid quality, just a little too short for me I think. I'm 6'3 tall, anyone shorter the length is fine.

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Shorts that come up short

Comfy shorts that seem well made. Unfortunately I feel annoyed that they don’t come down to the knees as the images suggest. These look ridiculous when you have knee pads on as you get a gap between the top of the knee pad and the bottom of the shorts. So these shorts will be relegated to road cycling duties. If they were longer and covered the knees they would be great!

Excellent shorts

Very comfortable to wear due to the stretchy fabric. Great quality and seem to be wearing well. A 3/4 length version would be absolutely fantastic

No but for the price

Good fit comfortable material more pockets will be nice

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Good product


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Size Guide

Size Guide Visual

Additional Product Information


Main fabric

  • 15% Spandex
  • 85% Polyamide

Our tip: wear undershorts for added comfort!

At Rockrider, we recommend adding undershorts with a pad under your 900 mountain bike shorts. The undershorts fit discreetly under your shorts. We must say: it is certainly more comfortable with a pad. The 500 and 900 mountain bike undershorts are compatible with the 900 mountain bike shorts.

Care tips

Machine wash at 86°F. Synthetics cycle. Turn the article inside out. Use a minimal amount of laundry detergent. Do not use fabric softener. Line dry in a warm, ventilated area. Do not tumble dry.Do not dry clean. Do not bleach. Do not place on a heater to dry.

Product tests

Our team of product designers based at the B'Twin Village in Lille, France is continuously working to make cycling more comfortable for our users. Our mission is to create products that meet the specific cycling needs of our users and to eliminate obstacles to a good cycling experience. We then test our products in the field, as we are convinced that only by subjecting them to real world conditions can we continuously improve our products.



Product testing

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.

Care instructions

Machine washable. Do not tumble dry.

Superior quality. Unbeatable prices.

For 40 years, Decathlon has delivered the best value in the retail sports industry by offering high-quality, sustainable and cost-effective products.

Decathlon makes the difference
  1. product-research

    Research and development

    delivers high-quality cost-effective products

  2. State-of-the-art production processes

    minimize manufacturing costs

  3. Optimized supply chain

    reduces retail prices

  4. laptop-checkout

    Minimal retail footprint

    lowers overhead and indirect costs


Size Guide Visual