First Impressions: Alpinestars Supertech RK-10 Plasma Knee Braces

Alpinestars Supertech RK-10 Plasma Knee Braces

I'm the reviewer from MX Locker and I spent time testing the Alpinestars Supertech RK-10 Plasma knee braces to see how they perform on and off the bike. These braces promise a mix of protection, comfort, and a lightweight, race-ready feel—but real-world fit and comfort are everything. Below are my detailed impressions after fitting them, putting them on the bike, and riding laps.

First impressions and fit

Right away I noticed a significant pressure sensation on the front of my calf. Inside the brace there's a reinforced, almost Kevlar-like pad that presses quite firmly against the front of the leg. It’s noticeable the second you strap the braces on.

I also found a small but important design detail: the top cap catches on the lower cap underneath it. When you're wearing pants this may not be as obvious, but that kind of snag can be a real nuisance—especially when your knee is extended and your pant catches so you can’t move your leg.

“There’s nothing worse than the feeling of your knee fully extended, your pant catches and you can’t move your leg.”

Compared to what I normally ride in (I wear a Mobius brace), the RK-10s feel slimmer at the top but a bit bulkier around the knee joint. That slimmer upper profile gives a more connected feel to the bike, but the bigger knee area and the calf pressure are unfamiliar and worth noting if you’re switching brace types.

One convenience: I didn’t need to re-adjust my boot strap or change my pant setup when switching from my Mobius brace—the same pants and boots worked fine. What I don’t like is how much vertical movement the brace allows even with the straps tightened. I had both braces cinched down and still noticed slippage up and down the leg, which could affect stability over a full ride.

On-bike feel and comfort

When I got out on the bike the most obvious issue was pinching. Squatting down in the pits or when you’re on the peg, the RK-10s can pinch the back of the thigh. On corners—say a left‑hander where your right leg is bent and riding on the peg—you can feel a persistent pinch that distracts you from riding. The strap layout and how the brace contours around the leg seem to be the main culprits.

That said, the inner profile is thin and race-oriented. I liked how connected it made me feel to the bike. Compared to thicker, more padded braces, the Supertech RK-10s feel racy and low-bulk on the inside.

One observation on geometry: the brace felt slightly bowed out on my leg. If you squat and the brace doesn’t track your natural leg alignment, you end up with pressure points where it shouldn’t be, which likely explains some of the pinch when bending. For riders with very straight legs this could be more noticeable than for riders with different leg shapes.

Pros and cons (quick summary)

• Pros: Slim inner profile gives a connected, racy feel; solid overall protection and lightweight construction; prevents hyperextension and provides secure support during aggressive riding.
• Cons: Noticeable pressure on the front calf from reinforced padding; top cap can catch on the lower cap; strap system can cause pinching behind the thigh when bent; more vertical movement on the leg even when strapped tight; slight bowed fit can create uncomfortable pressure points.

Final verdict

The Alpinestars Supertech RK-10 Plasma is a solid knee brace with a race-oriented feel and good protection characteristics. If you prioritize a slim, connected inner profile and lightweight construction, you’ll appreciate a lot about this brace. But the strap system and how the brace sits on the leg produced uncomfortable pinching for me, and I experienced more up-and-down movement than I’d like.

If I had to rank the three braces I tested, I placed the RK-10 third overall—not because it’s unsafe or poorly built, but because its strap layout and fit created distractions I didn’t want mid-ride. With some adjustments to the straps or minor fit changes, it could move up in my ranking.

Where to buy

If you want to check them out, the Alpinestars Supertech RK-10 Plasma knee braces are available here: https://mxlocker.com/product/alpinestars-supertech-rk-10-plasma-knee-brace-qzlbw

Bottom line: try them on and ride them if you can—fit is highly personal when it comes to knee braces. The RK-10s are a great choice for riders seeking a slim, performance-oriented brace, but be mindful of potential pinching and strap adjustments.