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Mountain Bike Shorts ST 500

Sale price: $25.00 Regular price: $44.99

Lightweight and durable shorts with built-in undershorts and clever pockets. Enjoy both support and freedom of movement on your bike. Bonus feature: snap your gloves directly to your shorts.

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Size: Select a size
Size Guide
Sale price: $25.00 Regular price: $44.99

Free shipping over $35

Final Sale: No returns or exchanges

Free returns

Free pickup

San Francisco, 735 Market St. Options

Select an available color and size to see options.

Model: 8500913

Product Features

A photo of the Mountain Bike Shorts ST 500 in use

Mountain Bike Shorts ST 500 | Our team designed these shorts for mountain biking in warm weather for more than 2 hours.

Lightweight and durable shorts with built-in undershorts and clever pockets. Enjoy both support and freedom of movement on your bike. Bonus feature: snap your gloves directly to your shorts.

Seat comfort

Ride comfortably for up to 3 hours with the built-in foam pad.

Abrasion resistant

Dare to go anywhere! The abrasion-resistant fabric won't snag on vegetation.


Take everything you need in the handy pockets.

Freedom of movement

A comfortable fit and stretchy fabric for easy riding.


Added comfort: gel strips to keep undershorts in place.

Product Lifestyle Image Gallery

Image Gallery

Mountain Bike Shorts ST 500,black 

Mountain Bike Shorts ST 500,black 

Mountain Bike Shorts ST 500,black 

Mountain Bike Shorts ST 500,black

Product Customer Reviews

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Mountain Bike Shorts ST 500,black
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Great value MTB shorts

Bought for my son, these shorts are well made and have good features like the phone pocket

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Mountain Bike Shorts

These shorts are well made, waterproof, practical and comfortable. A bargain at this price.

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Great Shorts

Very comfortable shorts over 4-5 hours of trail riding.

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shorts had a hole in it. why were they available ?

The shorts had a rip in them. I'm amazed it was on the shelf available for sale when it was defective. Now I have a long drive back to return. Best to carefully look over garments before purchasing

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Hi Shane,

I'm sorry to hear about your experience with our ST 500 Mountain Bike Shorts. We always strive to create exceptional experiences for our customer and it seems like this time we've missed the mark. When you're able to, please come back to your closet store and we'll be happy to return these shorts for you.



Great shorts!

Excellent product, great quality. Good value for money.

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Very comfortable and practical

Great shorts for my very day commute to work. They fit perfectly and are really comfortable

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Way too small

Size is about 2-3 sizes too small

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Hello John, 

Thank you for taking the time to leave a review. We are sorry that the product did not fit you perfectly. 

Although we try to accommodate our design and size guides, our customers always advise taking one or two size up compared to your regular size. 

If you are not satisfied with the product, you can always exchange it at the store for another size. 

Do not hesitate to ask our advisors for advice if you have any doubt about the size you need. It is important to feel comfortable in your clothing! 

Please be assured that we are doing our best to adapt our offer and make the size selection easier for all our customers.

Can't wait to welcome you to our store again.

Thanks & Best Regards,

Decathlon Brampton Team

Too big

Go true to size

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Horrible Pocket

The shorts themselves are great, they fit well are comfortable, strechy and pretty nice. However the phone pocket is HORRIBLE your phone and whatever you put in there will bop up and down as you pedal (its fine while you go down though. I would recommend getting a different one from Decathlon but probably a different model.

Not great

Too small, not great quality

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Good shorts but maybe buy a size larger

Good quality shorts but lack of pockets and maybe buy a size larger

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Exactly as needed

Very comfortable, but undersized. Would definitely go a size up on normal fit.

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Inner shorts are tight

Just bought a pair in large size. The outer shiets are a great fit but the inner shorts are very tight particularly restrictive around the thigh. I don't wont to go up a size as the outer shirts won't fit. Will probably buy a separate inner shirt on a better size.

Sizing issues

I have purchased similar shorts from Decathlon in the past and am a medium. Website states that the medium size is 93 to 98 cm as does the label on the shorts. On receiving the shorts they are far too small, I measured the shorts as being a 76cm, which is 17cm smaller than advertised.

Good shorts

Good shorts a pity about the liners The shorts are well designed and comfortable with well placed pocket The liner seem a strange shape so I wear my older inners with the shorts

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Size Guide

Size Guide Visual

Additional Product Information


Main fabric

  • 12% Spandex
  • 88% Polyester cationic


  • 100% Polyester cationic

Inner fabric

  • 100% Polyester cationic

Padding - Inner fabric

  • 6% Spandex
  • 11% Polyester cationic
  • 23% Polyamide
  • 60% Polyurethane

Padding - Outer fabric

  • 20% Spandex
  • 80% Polyamide


  • 29% Polyurethane
  • 71% Polyester cationic

Keep your gloves handy!

When mountain biking, gloves are often the last thing you put on and the first thing you take off. To keep your gloves handy without having to dig through your pockets, these shorts have a loop at the waist. You can snap your ST 100 and ST 500 gloves on them using the press stud to keep them handy at all times.

About these shorts...

To enjoy your rides more, these shorts feature 2 components: a stretch fabric to follow your every move and a durable fabric to prevent snags and tears. They are also lightweight and breathable for better moisture management. To give you greater freedom of movement when mountain biking, the waistband is elasticated for better fit and stretch. The cut was designed to keep the crotch from catching on the edges of the saddle.

Clever pockets

To have everything you need when you head out for a ride, these shorts have clever pockets: - At the back, you'll find a secure zip pocket to hold keys, an ID, a debit card etc. - There is a waterproof secure zip pocket at the back of the thigh (easy to access, even with just one hand) that is specially placed to keep your smartphone safe if you fall. - Along the thigh are 3 pockets for cereal bars: just push up to slide them out.

The evolution of these shorts: from our ideas to your input

We originally wanted to create a pair of shorts designed especially for mountain biking and to carry everything you need when riding. Our team of 5 designers spent 18 months working on studies, technologies, designs, prototypes and lab tests and gathering your input. We went to France and Italy to meet with around 30 mountain bikers to do functional and usage tests. The end result? A product that suits your sport and your needs!

Shorts, undershorts, pad? our tips!

The ST 500 shorts are sold with removable undershorts to change undershorts without changing the shorts (just like you would an undergarment)! The shorts and undershorts are sold attached. Before riding, remember to separate them! Why? Because each has their own role to play: - The undershorts are worn against the skin for comfort and support. - The shorts give you freedom of movement when riding.



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.

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