There were only a very few SixSixOne pads that stayed put. I know this because I owned a lot of different ones. The EVO with the D30 impact material were all-day comfy and stayed in place; but, alas, it appears they have been discontinued. I never owned the Kyle Straits but they got rave reviews and are sorely missed by a lot of people.
I have so far been impressed with the 7iDP Protection guards that I have. I just got the Flex knee/shins and they stayed put for a 16-lap day of downhilling at the bike park. They make a knee-only version that I have to think would be every bit as good. If you prefer a hard-cap, look at the Control line.
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Originally Posted by Mark Twain
"Don't argue with stupid people; they will drag you down to their level and then beat you with experience."