My right knee was blown out 2 years ago, so I bought a pair of these to protect the repaired knee, and the good knee.
I just got back from racing the Baja 500 with these braces: here is my review.
Over a long period of time, blisters formed on my knee caps. I think the main issue is that my pants are too tight.
The braces seem to offer great support. I do feel secure while wearing them. There is a fine line between having the adjustments too tight, and causing leg pump, or having them to loose, and not staying in place.
The movement is very smooth and the range of motion is plenty for dirt biking and snowboarding. The knee part of the brace swivel which allows the perfect motion for shifting/braking. The connector to the boot offers great security.
The bad thing is the bulkiness. When I first rode with these braces, my feet kept being tossed from the foot pegs. I finally realized that I wasn't gripping with my knees the same with these on. After an hour or so, I adjusted and now don't have that problem. I do notice that my feet slip sideways off the pegs still, its rare, but something that probably will always happen while riding with these. I ride a 450r, and with these braces it feels like I'm riding with a desert tank. If you already have a desert tank, it feels like youre riding a whale.
Overall I'm pleased. It however, took me a few rides to say that.