Motorcycle knee braces at Moto Central currently comprise four Alpinestars off-road designs: the RK-1 PLASMA, RK-7 PLASMA, Supertech RK-10 PLASMA and youth-specific Bionic 5S. Each combines an articulated supporting frame with an impact protector, but the materials, sizing and intended rider differ across the range.
Knee braces are commonly chosen for motocross and other demanding off-road riding. They should not be treated as a guarantee against injury or as a replacement for medical advice. Alpinestars states that these braces are designed to support the knee and reduce the risk of specified ligament and meniscus injuries, while their EN 1621-1 rating relates to impact protection at the knee.
Compare the Alpinestars knee brace range
The RK-1 PLASMA uses a hybrid frame made from flexible composite over-injected on a performance polymer blend. It comes in combined S/M and L/XL sizes and uses four straps to hold the brace in position.
The RK-7 PLASMA moves to an asymmetric fibre-reinforced frame and a free-floating Nucleon PLASMA knee protector. Its four-point hinge follows the knee joint, while extension stops allow the maximum opening angle to be adjusted between 0 and 30 degrees.
The Supertech RK-10 PLASMA uses a 34-layer forged carbon-fibre frame. It retains a low-profile four-point hinge and adjustable extension stops, but is aimed at riders choosing the most rigid and weight-conscious construction in this group.
The Bionic 5S Youth is the dedicated junior option. It uses a flexible composite and fibre-reinforced polymer hybrid frame rather than simply shrinking an adult RK model. This matters because brace geometry, strap position and joint alignment must suit the rider, not only fit around the leg.
Alpinestars lists all four current models with an EN 1621-1:2012 Level 1 knee protector. The RK models use Nucleon PLASMA impact protection with replaceable knee cups. Certification and construction details apply to the named product and should be confirmed on its listing and user guide.
How to choose and fit a knee brace
- Choose adult or youth geometry first: the Bionic 5S Youth is the relevant starting point for a junior rider. Do not select an adult brace solely because its straps can be tightened.
- Use the brand size chart: take the measurements in the positions specified by Alpinestars and compare them with the current chart for that exact model.
- Align the hinge: both sides of the articulated joint need to track the knee correctly through flexion and extension.
- Set the straps in the stated order: follow the supplied user guide. Straps should hold the brace securely without causing numbness, pinching or restricting normal control of the bike.
- Check the riding position: test the braces with riding socks, trousers and boots. Confirm that the boot cuff, brace and trousers work together without snagging or forcing any part out of position.
- Review extension stops carefully: adjustable stops are a setup feature, not a medical prescription. Seek qualified clinical advice if a brace is being considered after an injury or for an existing condition.
Knee braces and knee guards are different
A brace uses a hinged supporting structure around the joint as well as impact coverage. A conventional knee guard is primarily designed to cover the knee, and sometimes the shin, against impact. Riders who do not need a framed brace can compare inserts and standalone guards in the motorcycle knee protectors collection. Junior riders can browse the wider kids motorcycle gear range for youth-sized helmets, clothing, boots and protection.
Why buy knee braces from Moto Central?
Moto Central stocks the adult RK-1, RK-7 and RK-10 alongside the dedicated Bionic 5S Youth, allowing riders to compare the complete current Alpinestars progression in one place. Individual product pages show the available sizes and model-specific construction, while our range of replacement padding and brace parts can help maintain compatible equipment where stocked.
Customer questions
Do knee braces prevent ligament injuries?
No brace can guarantee that an injury will not occur. Alpinestars describes these models as providing structural support intended to reduce specified risks. Correct sizing, setup and use remain essential.
What does Level 1 mean on these braces?
It refers to the EN 1621-1:2012 impact-protection rating of the knee protector. It does not grade the brace as a medical device or guarantee ligament protection.
Can an adult RK brace be used by a child?
Use the youth-specific Bionic 5S where its fit range is appropriate. An adult brace should only be considered if the rider meets the manufacturer's measurements and the hinges and straps align correctly.
