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Rockrider ST500 Mountain Bike Undershorts Men's

Sale price: $20.00 Regular price: $24.99

Are you looking for a good balance between support and simplicity for your rides? With their thick pad and breathable fabric, these ST 500 mountain biking undershorts keep you comfortable and cool.

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Sale price: $20.00 Regular price: $24.99

Free shipping over $49

Final Sale: No returns or exchanges

Free returns

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San Francisco, 735 Market St. Options

Select an available color and size to see options.

Model: 8529624

Product Features

A photo of the Rockrider ST500 Mountain Bike Undershorts Men's in use
A photo of the Rockrider ST500 Mountain Bike Undershorts Men's in use

Rockrider ST500 Mountain Bike Undershorts Men's | These comfortable mountain biking undershorts are designed for rides lasting over 2 hours.

Are you looking for a good balance between support and simplicity for your rides? With their thick pad and breathable fabric, these ST 500 mountain biking undershorts keep you comfortable and cool.

Seat comfort

Ride comfortably for up to 3 hours thanks to the ergonomic 12 mm foam pad.

Moisture wicking

Stay dry: the airy mesh fabric quickly wicks perspiration.


More support for more comfort thanks to the elastic band and gel bands.


You just need one: these undershorts are compatible with our men's MTB shorts.

Questions & Answers

Product Customer Reviews

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Could be more comfortable

Its good enough and perfect fit and works as it supposed to be.

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In the top

In the top

Good Product đź‘Ť

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A Must product

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Excellent product

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its decathlon. what else to say.

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Good product and value for money.

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I bought it for just 199/- during clearance sale... A good product but this time the elastic is getting loose easily than earlier purchase.

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Very good for the price you pay

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Poor elastic. Useless in a very short period of time when elastic lost it's elasticity

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Very good at the price of 199. OK for rides upto 100km

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Worth the price

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Good product

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Size Guide

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Additional Product Information


Main fabric: 100.0% Polyester ; Padding - Inner fabric: 100.0% Polyester ; Padding - Outer fabric: 80.0% Polyamide, 20.0% Elastane

Are these undershorts supportive? we explain all.

Bibless undershorts can be much more practical. But do you get enough support?To guarantee the support you need, even without straps, we have made a pair of undershorts that hugs your body just like boxers. The elasticated waistband adapts to fit you and stays in place with no adjustment needed.And to stop the shorts riding up as you cycle along, there are gel bands at the bottom to keep your undershorts just above your knee.

A second skin with comfort to boot.

Feeling comfortable in the saddle is a top priority when you're on the go for several hours!For maximum comfort, even when you're hurtling down mountain bike trails, your undershorts have an ergonomic 12 mm foam pad.Besides making the saddle more comfortable, the pad reduces rubbing so you won't get chafed.

Several layers for less heat?

In the middle of summer in particular, you need to get rid of heat quickly.That's why the ST 500 undershorts have a breathable foam pad and mesh fabric, to wick away perspiration quickly.The result is that you don't warm up, even though you're wearing 2 layers of shorts.

How our ideas and your feedback made these undershorts.

We entrusted our mountain biking team with the task of designing bibless undershorts that give you a good balance between simplicity and support.It took 5 people 18 months of studying, designing, prototyping and running lab tests... And we also had your feedback.We traveled to France and Italy to meet up with around 30 intermediate mountain bikers and run a series of functional tests in real situations.The result was a product that's suited to your sport and meets your needs!

Shorts, undershorts, pad? here are our tips!

Undershorts are to MTB what kilts are to Scotland: you wear them against your skin!To avoid chafing, we therefore recommend changing them and washing them as if they were underwear.And when you're riding, your shorts and undershorts should never be attached.Why? Because each has their own role to play:- The undershorts stay in place for comfort and support.- The shorts move with you for better freedom as you cycle along.

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


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