Btwin Rockrider 20 Review

The Btwin Rockrider 20 inch kids bike packs a ton of punch into its sub-$200 price tag. All of our testers raved about its smooth ride, while we were incredibly impressed by its unmatched quality and performance for the price. So it’s no surprise that the Decathalon Btwin Rockrider was enthusiastically received by our testers and their parents.

What else makes this little 20″ bike so awesome? The Rockrider’s durable frame has a lifetime warranty and its dual handbrakes are impressively responsive for this price point. To top it off, it doesn’t have a coaster brake!

Young rider smiling while riding the Decthalon btwin 20 inch Rockrider

“Can I please ride the white bike?” Specs aside, we can’t emphasize enough just how much our testers loved the Rockrider! Read our review to learn why the Rockrider is hands down our favorite 20 inch budget bike.

Btwin Rockrider 20 Inch ST100

RATING: Highly Recommended

MSRP: $149

BEST FOR: Everyday neighborhood riding on paved or all-terrain surfaces

SEAT HEIGHT: 23.25″ – 30.25″

WEIGHT: 24.3 lb.


BRAKES: Dual handbrakes


  • Unbeatable quality of build for its price
  • Responsive dual hand brakes that are easy to adjust (and no coaster brake!)
  • Thickly-padded saddle
  • Lighter than similarly priced bikes
  • Lifetime warranty on frame
  • Compatible with training wheels (but not included)
  • Available in three different model levels
  • Height adjustable handlebars (on all models but the ST900)


  • Does not come with kickstand (but one is available for $10)
  • Sticker decals likely to come off with time
  • On the heavier side for a 20 inch bike (but still lightweight for its price)

Btwin 20 inch Bike Models

Btwin (Decathlon’s house brand) offers two different lines of kids bikes. The Rockrider line is designed with a mountain bike look and functionality (on higher-end models). The urban Original line is designed for city use on smooth, paved surfaces.

decathlon btwin bikes 20 inch models, Rockrider and Original
Btwin Rockrider vs. Btwin Original

The Rockrider line, which this review centers around, comes in 3 different models that vary in color, gearing options, and components. The difference between these models is explained in the next section.

The Original line is available in 2 different models. The base Original 100 model is a single-speed, while the Original 500 model is 6-speed and also comes with metal fenders and a basket.

Rockrider 20 ST100 vs. ST500 vs. ST900

The Rockrider 20 inch is available in three different models – the ST100, ST500 and ST900. All three models have the same size frame, but they vary in color, gearing, and components.

The Rockrider model that is best for your child really depends on how your child plans on using it. The more aggressive your child’s riding style (as well as the trails they are riding), the higher the Rockrider model number is appropriate for them.

Suspension ForkNoYesYes
Derailleurn/aMicroshift grip shiftShimano Altus trigger
BrakesV-brakesV-brakesMech. Disc

Based on our experience, we would recommend the single-speed ST100 for timid riders who ride mainly around town, the geared ST500 for adventurous neighborhood riders who want a shock to help do small bunny-hops and jumps, and the geared ST900 for true single-track riders hitting basic to intermediate trails.

In the remainder of this review, we will be focusing mainly on the ST100, but keep in mind that all models of the Rockrider 20 inch have the same size frame and will fit the same size child.

Decathlon Btwin Rockrider ST100 – Test Results

We put the Rockrider 20 ST100 to the test with three different riders, ages 6 and 7. With bike skill levels ranging from timid beginner to confident cruiser, we were pleasantly surprised at how well the bike was received and performed for all types of riders.

Offering the perfect mix of simplicity and brawn, the single-speed Rockrider ST100 wasn’t too much bike for our more timid riders, but still offered enough “spunk” for our more advanced riders.

Young girl riding the Rockrider 20 inch btwin bike

For those riders who want gears or a suspension fork, the higher-end ST500 or ST900 provide a great bang for your buck. But for those on a tighter budget or who don’t need the added complexity of gears, the Rockrider ST100 is hands down the best 20-inch bike you can buy for under $200.

Neighborhood Performance

Although the higher-end Rockrider models are certainly mountain capable (on basic trails that is), the Rockrider ST100 is really best suited at home for cruising around the neighborhood. With a mountain bike style frame and all-terrain tires, the Rockrider ST100 gives the look of a rugged, big kid bike that appeals to young riders. But it is smartly specced out to suit the more basic needs of neighborhood riders.

With responsive dual-hand brakes, no coaster brake, and no gears to worry about, the Rockrider 20 is simple and easy to use. Even our timid 6-year-old tester, who was trying out a 20″ bike for the first time, was easily able to hop on and pedal away.

Boy riding the Decathlon Btwin 20 inch Rockrider

Our more experienced testers, some of whom ride higher-end brands, commented on the smooth and “easy” ride of the Rockrider 20 and happily rode it around with friends.

All-terrain Performance

As a single-speed bike, the ST100 really isn’t designed to tackle true all-terrain trails, but its knobby tires certainly make it suitable for smooth, dirt trails with minimal elevation changes. We even had our timid rider take the Rockrider on a gravel path and the bike happily obliged and no problems maintaining traction.

riding the rockrider 20 bike in the dirt

What size child fits on the Btwin Rockrider 20?

We tested the Rockrider ST100 20 inch on three kids ages 6 and 7 whose height ranged from 46″ to 50″. We found the bike to offer a great fit for all three kids. With a seat height ranging from 23.25″ – 27.25″, there was plenty of room for adjustment for all of our testers.

boy riding the rockrider 20 inch on a paved road

On the tall end, our 50″ tester with a 28.5″ inseam also comfortably fit on the larger 24 inch Rockrider with its seat set to its lowest at 26″. As a result, to allow maximum room for growth, we would recommend kids who are 49″ tall with at least a 28″ inseam to move up to the 24″ size.

Below you can see our 50″ tall tester on the Btwin 20″ Rockrider, next to his 51″ sister on the 24 inch Rockrider.

a girl on a 24 inch Rockrider next to a boy on a 20 inch Rockrider kids bike

For kids on the shorter end, Decathlon does not offer the Rockrider in a 16″ wheel size, but they do offer 16″ and 14″ bikes in their Original line.

Components and Features of the Btwin Rockrider 20 ST100

Single-speed Simplicity

The Rockrider ST100 20 inch is single-speed with a 3.6 gain ratio. This mid-range gearing is just right for riding around the neighborhood. It’s low enough to allow kids to easily start pedaling the bike without much effort, but high enough to allow them to gain speed without having to spin their legs excessively fast.

For those speed seekers who want to gain a lot of speed on a long straightaway, the single speed Rockrider is geared a bit too low and the geared Rockrider models would be a better option.

close up of the drivetrain on the Decathlon 20 inch Rockrider bike

Responsive Hand Brakes with NO Coaster Brake!

One feature that we love, love, love about Decathlon bikes is their quality hand brakes. Unlike the many other “budget bikes” we have tested, the brakes on all five of the Decathlon’s kids bikes we have tested work amazingly well straight out of the box – without any adjustments needed. In addition to not needing adjusting, the brakes are very responsive and require little effort for smaller hands to engage.

If the brakes do need adjusting, Decathlon makes it easy by proving an easy-to-use adjustment knob. Simply twist it forward to or back to adjust the tension on the brakes as needed.

close up shot of the btwin rockriders brakes with easy adjustment knob


The Rockrider places the child in a semi-upright position which is typically favored by most kids on 20 inch bikes. Not too leaned forward but not too upright, a semi-upright position helps kids feel comfortably centered on the bike, while still allowing them to lean into turns and power up and over jumps when needed.

In the image below, you can see how the geometry of the Rockrider compares to the Schwinn Koen 20 inch. The Rockrider has much lower handlebars than the Schwinn, which allows more weight to be placed on the front handlebars, which helps to increase maneuverability.

The handlebars of the Schwinn Koen are adjustable, but only to a higher position, which would greatly decrease the rider’s ability to quickly maneuver the bike.

comparison image of a girl on the Rockrider 20 inch and the Schwinn Koen 20 inch

Adjustable Height Handlebars

To help maintain a good fit on the Rockrider 20, the handlebars are height-adjustable on the ST100. By simply loosening the Allen bolt on the top of the stem, the handlebars can be raised about 1.5″ as your child grows.

The ST500 also has height-adjustable handlebars, but the more rigid and durable handlebar set up on the ST900 is not adjustable.

The height adjustable stem of the Decathlon Btwin 20 inch bike

Knobby Tires

The Rockrider comes with knobby tires that provide plenty of grip for tackling dirt trails, yet still offer a smooth ride on paved surfaces. For those who want to tackle true single-track, be aware that the tires on the ST100 are knobby but pretty soft, so they aren’t likely to last very long when ridden aggressively.

The ST500 and ST900 models feature a more durable knobby tire.

Knobby tires on the Decathlon btwin 20 inch Rockrider

Padded Saddle

Another rare find in a low-priced bike is a true, padded saddle. Ergonomically shaped to fit smaller-framed kids, as well as with plenty of thick cushioning, the Rockrider 20 seat was well-loved by our testers.

ergonomic and padded saddle on the btwin rockrider 24

Sticker Decals

The one place where the Rockrider’s price point is apparent is its sticker decals. While we had no issues with the decals coming off, with time we anticipate they will begin to peel.

sticker decals on the btwin rockrider 24

Btwin Rockrider 20 Bottom Line and Comparisons

From geometry to performance, the Decathlon Rockrider 20 inch is an excellent single-speed bike for neighborhood riders. You simply can’t buy a better 20-inch bike for under $200, and trust us – we have tried!

For those who need gears (versus want – trust us… gears are a challenge with younger kids, so only get them if they need them!), the higher ST500 and ST900 models would be a better fit.

What do I lose by buying a cheaper 20 inch bike at a big box store?

The four main benefits of the Rockrider over other budget brands are:

  • Weight – Lower-priced bikes weigh up to 5 pounds more
  • Geometry – The Rockider places the child in a semi-upright position that most kids prefer. Lower-end bikes typically place the child in a very upright position that makes it more challening for riders on 20″ bikes to quickly manuver the bike.
  • No Coaster Brake! – We have yet to find a more affordable 20 inch bike with reliable dual hand brakes and no coaster brake (backpedal brake)
  • High Quality of Build – The Rockrider provides a smooth, comfortable, and sturdy ride

What’s the benefit of spending $50 – $150 more on a 20 inch bike?

Quality 20 inch bikes can vary widely in price! Typically, the more expensive the bike, the better quality components. This difference can be seen in the 3 models in the Rockrider line.

  • Even lighter weight – Higher-end bikes are built with aluminum frames, versus heavier steel. The Rockrider ST100 and ST500 have steel frames while the ST900 is aluminum.
  • Gears – Gears on 20-inch bikes can be a blessing and a curse. Shifters and derailleurs easily break if not properly taken care of, especially gearing systems on budget bikes. If you want gears on a 20-inch bike, don’t go cheap!
  • Higher quality drivetrain Rigid, durable, yet lightweight bike components don’t come cheap. In most cases, higher-quality parts on the drivetrain can lead to less chain deraillments and more responsive shifting.
  • Stickers vs. Integrated decals – Decals always last longer and look better than stickers

What is the Btwin brand and where can I purchase them?

The Btwin brand of bikes are available at or at Decathlon stores. While new in the US, Decathlon is a well-known and well-established international brand with over 40 years of experience.

Decathlon is a unique sporting goods store in that it only sells its own house brands. Btwin is Decthalon’s brand for its entire bike line – ranging from technical adult mountain and road bikes to balance bikes. With everything from research and development, to distribution all done in-house, Decathlon is able to produce quality products at lower prices.

FTC Disclosure: Affiliate links are included in this review.  No monetary compensation was provided for this review, however, the reviewed product was supplied by the manufacturer or distributor to help facilitate this review. All opinions and images are that of Two Wheeling Tots LLC.  All content and images are copyrighted and should not be used or replicated in any way. View our Terms of Use.

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