[Test] Alpinestars Fluid Tech Carbon Knee Brace


We have tested the Alpinestars Fluid Tech Carbon knee braces for a month and a half riding dirt jumps and pumptracks of Barcelona, Spain. Although these knee braces are not made for everyone, but only for those who have suffered knee injuries and surgeries, they are still pretty good for riding if you want to be more protected. Let’s learn more about them and see how they performed.


As we have just said, they are not a conventional knee guard, the Fluid Tech have been designed for motocross racers and riders that have suffered knee injuries and surgeries on their ACL’s, LCA’s, meniscus, and so on. In our case, we have had 3 knee surgeries so we have to ride with a knee brace like that if we want to keep doing what we love. Until now, we have been riding with the cheaper version, the Fluid Pro X-Blend in both knees, so riding with the Fluid Tech Carbon has been awesome.

This is what Alpinestars says about the Fluid Tech Carbon knee braces: “Constructed from an innovative advanced carbon polymer compound for improved strength and performance, the Fluid Tech helps reduce the risk and severity of injury by preventing excessive hypertension of the knee in an accident. Thanks to innovative engineering the Fluid Tech is ultra-lightweight and offers a highly customizable and secure fit, while affording improved directional movement of the knee articulation while riding.”


• CE Certified to EN 1621-1 (K type B), and extremely lightweight, strong construction from a new and advanced, high-performance carbon polymer compound that retains its performance attributes in both extreme warm or cold climates.
• Incorporates DEFT – Dynamic ErgoFit Tech – an innovative, reduced material design construction for improved weight-saving and excellent ergonomic performance.

• Innovative knee pivot system incorporates tool-free poly-centric hinge system for fast, easily exchangeable extension stops (0, 5, 10, 15 and 20 degrees) to prevent hyperextension injuries.
• Ergonomically sculptured and ventilated knee cup system constructed from semi-rigid TPU for durability, backed by shock-absorbing PU memory foam for comfort.
• Highly ventilated, channeled padding and mesh zones for superb airflow cooling.

• Customizable, versatile and secure fit afforded by size adapter system.
• Fine-tuning of personalized fitment offered by knee width adjustment spacers (1mm, 2mm and 3mm, both sides), supplied as standard.
• The Fluid Tech comes with anatomically optimized ErgoFit spacer kits for improved directional articulation performance and position stability. Kit includes new medial-side spacer insert to promote closer contact with the bike.
• Correct positioning of knee cup is secured accurately with top and bottom elastic straps, allowing multi-directional freedom of movement, avoiding pressure points on the patella.
• New, soft, dual strap system promotes secure fitment of brace in all riding positions and includes combined buckle and Velcro® closures for rapid and easy mounting as well as comfort.
• Knee brace incorporates new lateral-side knee padding for comfort and to avoid pressure points.
• Comes in international sizes: S/M/L – XL/2XL.
• Price: $349.95

During the first week we rode without any extension stoppers that blocked the hyperextension of the knee brace, but after being recommended to add them by a friend that has suffered a couple knee surgeries, we chose to add the 20 degree extension stopper to have a better support. Above these lines you can see how the knee brace looks with them. Your knee is never straight, it is slightly bent, so the chances of injury are lower. It doesn’t affect your riding because your legs are never straight, you have to bend your knees for pumping and jumping. The adjustability is just perfect.

The carbon body is tough. It is constructed from a new and advanced, high-performance carbon polymer compound that works as good as it looks. When the pedals have hit it or we have crashed into the dirt, we have never felt anything. While those aren’t signs of preventing a knee injury, we had a small impact on our foot underrotating a 360, which in the end wasn’t that bad, but that could had been worse if we hadn’t worn the Fluid Tech.

The new lateral-side knee padding is super comfy. While you can adjust its fitment adding adjustment spacers, it keeps your knee supported all the time offering a better comfort than the Fluid Pro X-Blend. Same for the straps. The new, soft and clean design for the insides is more comfortable and those small shiny lines maintain the knee brace in its place since you put them on. Although we ride with skinny jeans, we sweat, so while the session is on we have found ourselves putting the Fluid Pro X-Blend back to its place, but not with the Fluid Tech. Also, while you walk you can feel that even though both knee braces have the 20 degree extension stoppers, the Fluid Tech Carbon is more rigid.

If we compare both knee braces versions, although they are very very similar, the Fluid Tech Carbon wins over the Fluid Pro X-Blend because of its construction, design, durability, comfort and rigidness.

Below you have three photographs where you can clearly see a few differences between one and another.

Aesthetically they look the same, but the construction of the Fluid Pro X-Blend is from fiberglass, while the Fluid Tech are made from carbon, which is tougher.
The lateral padding of the Fluid Pro X-Blend has nothing to do with the one inside the Fluid Tech Carbon knee braces. They do really work and are offer the same adjustability, but the comfort on the Fluid Tech’s is excellent.
There have been times where we have found the Velcro unstrapped after a riding session due to technical movements or leg pressure. It never happened on the Fluid Tech.


In general, knee braces aren’t cheap. If you search on the internet you will find different offerings, cheaper and way more expensive ones than the Alpinestars. Usually, knee braces are sold individually, but you can also find them as a set. We bought a set of Fluid Pro X-Blend knee braces 2 years ago in Andorra for $315. Anyhow, if you are thinking on getting a knee brace because you have had an injury or have gone under surgery, and want to ride your bike without having to spend all your savings in one, we would recommend you to give the Fluid Tech Carbon a try for just  $349.95 each. They are comfortable, adjustable and rigid, just how they should be.

For more information about the Alpinestars knee braces, please visit: alpinestars.com

Text and product photos: Héctor Saura
Action photos: Alex Domingo
Rider: Héctor Saura


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