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Mountain Bike Shorts ST 100

Sale price: $16.99 Regular price:
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Sale price: $16.99 Regular price:

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Model: 8381864

Product Features

A photo of the Mountain Bike Shorts ST 100 in use

Mountain Bike Shorts ST 100 is designed for occasional cycling in warm/hot weather (1 hour rides).

The ST 100's built-in foam pad is designed especially for men. Unlike classic shorts, these shorts absorb vibrations and prevent rubbing and irritation.

Resistant to wild vegetation

The "warp and weft" fabric withstands rubbing and snags.

Seat comfort

Preformed foam pad. The seams are positioned to prevent chafing.

Freedom of movement

Enjoy the wide cut, stretch fabric, and elasticated waist.


With undershorts that effectively wick away perspiration.


Take everything you need in the flap pocket on the right thigh.

Product Lifestyle Image Gallery

Image Gallery

Mountain Bike Shorts ST 100,black 

Mountain Bike Shorts ST 100,black 

Mountain Bike Shorts ST 100,black 

Mountain Bike Shorts ST 100,black 

Mountain Bike Shorts ST 100,black 

Mountain Bike Shorts ST 100,black 

Mountain Bike Shorts ST 100,black 

Mountain Bike Shorts ST 100,black 

Mountain Bike Shorts ST 100,black 

Mountain Bike Shorts ST 100,black 

Mountain Bike Shorts ST 100,black

Product Customer Reviews

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379 Reviews
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Mountain Bike Shorts ST 100,black
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Wayyyyy too small!

Recently lost lots of weight cycling, so ordered XL, which supposed were upto 4" too big, but couldn't even get them past my thighs. These are definitely not the right sizes in the size chart!!


excellent padding, and really nice fit. a very good buy, excellent value for money.


I’ve started using my bike more at the moment as something to do so thought I’d invest in some shorts for the padding more than anything. I went on and checked the sizes and it said I needed a Large pair, which is what I ordered. However, when they arrived they are way too small! There’s not extra give to the waist band and they’re far too small to even pass my knees properly. Other than size they seem to be really good material feels strong and durable, under shorts feel good and the padding is decently thick. I’d recommend but you need to order a size or two larger I’d suggest! Shame really especially as the larger sizes are currently out of stock and there’s a pandemic so god knows when they’ll be back in.

Excellent Product...Great Price

Purchased this product to use mountain biking...comfortable and functional at a great price. Recommend

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Good but not quite awesome

Needs a little more support towards the back

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Highly recommended

Great cycling shorts with good comfort and fit. Foam padding is good enough for 1 hour rides.

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THE SIZES ARE MILES OUT! I looked at the sizing which said 36" waist would be a medium - I was surprised as usually I'm an XL - shorts arrived and it says on the label even states 93-98cm (37-39inches) - are you having a laugh? A child would struggle to get these on - how have you got your sizing so so so wrong? Are you going to refund my postage? I made every effort to select the correct size - but your information is miles off!

Thank you for your feedback regarding these shorts.
For some reason, the online size guide uses the hips and not the waist for it's measurements.
If you this is not clear enough (and I don't think it is), please don't hesitate to return them to us.
Peter, Cycling Manager, DECATHLON
MTB Shorts

The quality of this product was excellent. Good for my cycling activity.

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Hello Christopher

Thank you for taking the time to write us a review regarding our product.
In Decathlon, we believe that to get this kind of information from our users is the best way to improve what we are doing.
We are glad that you are satisfied with our products :)
Do check out more variety of our products at 
Again, thank you for the feedback, don't hesitate to come down to one of our stores in Singapore. 
It will be with big pleasure that we will welcome you.
See ya! :)

Sports Leader | Decathlon Singapore Lab
Fine For A short Ride Only

It is a good one if you are riding for like 1hour. Won't recommend for long distance ride as the foam pad wont help much

Mountain Bike Shorts

I use these whilst riding my road bike. I find them comfortable and not as restricting as my normal cycling shorts.

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Great item

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Best for daily use

Best for long commuting and racing

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Good product, i will again for another product.

Good short i like it:)

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Very Good For XC use

The product's quality is very good. The cushion is very comfortable for long rides. And it is easy to wash and dry.

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Perfect and awesome

Very comfortable

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Hi Mohamad Amin, 

Thanks for sharing your thoughts on our ST 100 Mountain Bike Shorts, we're glad you enjoyed using it!

Do head down to any Decathlon experience store to check out what other mountain biking shorts we have on offer.

Hope to see you soon!

Your Friendly Neighbourhood Bicycle Guy,
Sport Leader, B'Twin - Decathlon SG Lab
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Size Guide

Size Guide Visual

Additional Product Information


Main fabric

  • 100% Polyester cationic

Inner fabric

  • 84% Polyester cationic
  • 16% Spandex


  • 56% Polyester cationic
  • 40% Polyurethane
  • 4% Cotton

Cycling shorts, the mountain bike rider's kilt

Don't forget: you wear cycling shorts without underwear. Why? Wearing underwear risks causing irritation. Your skin can rub against the seams and elastic of your underwear. Chafing, shearing, all combined with perspiration (heat + humidity)... this is quite the recipe for infections. That is why we design our shorts with anti-bacterial pads. Dare to wear shorts without underwear!

Our care tips

Machine wash inside out on a synthetics cycle at 86°F. Do not use too much detergent, and do not use fabric softener. It is best dried on a hanger in a warm, well-ventilated place.



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


Size Guide Visual