Product Colors and Sizes
Rockrider ST100, Mountain Bike Shorts, Men's
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.
Free returns
Free shipping over $30
Free pickup
San Francisco, 735 Market St. Options
Select an available color and size to see options.
Product Features

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.
Breathability
With undershorts that effectively wick away perspiration.
Pockets
Take everything you need in the flap pocket on the right thigh.
Product Lifestyle Image Gallery
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Product Customer Reviews

The listed is EU sizing, so the US size varies. An EU small is an US extra small, an EU medium is an US small.
Shorts are comfortable and fit well, only issue is that the padding is to thin.
Reasonable price and good quality
Purchased this product to use mountain biking...comfortable and functional at a great price. Recommend
Cheaply made. After tying the waist it ripped the elastic waste band. The shorts don’t ride well. Will be returning them
I wasn't expecting much from these but they are as comfortable as shorts that cost double, highly recommended.
not too flexible, but do the job
Used it once loved them
Comfy
I was a little apprehensive after reading a few reviews regarding sizing but they fit perfectly, so guessing that other shoppers are not checking the sizing guide and ordering waist instead of hip sizes. Overall quality appears to be good and the only downside is that the seat padding is not quite as thick and supportive as other products i've purchased from Decathlon, but for this price they are much better than I was expecting and I will be purchasing another couple of pairs as soon as they are back in stock. .
Ordered a medium as they allegedly fit a 39 inch waist. Couldn't get them past my knees so returned for an XL. Still too small. I can wear them but can't get onto my bike in them as they are so tight. I think you really need to work with your suppliers to get more accurate sizes. Really annoyed at the hassle. Avoid!
Make sure when you look at the sizing guide you measure your HIPS and not WAIST. No idea why as this is the first time in 35 years I've ever seen men's shorts/trousers measured in hips and not waist! Needless to say I ordered the wrong size!
Normally wear XL size. I have an old BTWin pair which look identical and fit really well. Bought XL but was very tight across crotch and rear but fine on legs and waist. Exchanged for XXL and they are feel too big in all areas, seems like a really big jump in sizes. It is a great price for padded baggy shorts and would still recommend for this but major issue with sizing.
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.
Size Guide

Additional Product Information
Composition
Main fabric
- 100% Polyester cationic
Inner fabric
- 84% Polyester cationic
- 16% Spandex
Padding
- 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.
Origin
Imported
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
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Research and development
delivers high-quality cost-effective products
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State-of-the-art production processes
minimize manufacturing costs
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Optimized supply chain
reduces retail prices
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Minimal retail footprint
lowers overhead and indirect costs

Rockrider ST100, Mountain Bike Shorts, Men's
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Heavy products return policy
If you return a product you will receive a refund for the purchase price plus any applicable sales taxes, less any non-refundable charges.
Decathlon will cover all shipping costs associated with your return except for items excluded from our return policy such as bikes, basketball hoops, snowboards, surfboards, tents, and other larger / heavier items.
Return costs for heavy products:
Weight Thresholds | Shipping within California | Shipping outside of California |
---|---|---|
> 9 lbs | $20.00 | $25.00 |
> 30 lbs | $50.00 | $65.00 |
> 100 lbs | $100.00 | $125.00 |
> 200 lbs | $200.00 | $230.00 |
If you return a product at any of our store locations, we will gladly help you find the best alternative product or refund you on the spot.
