One of the first things I bought for more heavier riding, particularly downhill when hitting up places like Whistler and NorthStar, are a pair of Troy Lee Designs Brian Lopes knee/shin guards.
These shin guards are quite comfortable. The two big concerns I have with leg armor in general is chafing from straps, and that they tend to slide down (especially when pedaling).
I was happy to find that there is no chafing on account of how they take a two layered approach. The inner layer is a soft shell that wraps around your leg (but is open in the back to stay cool), and the straps go around the shell. The outer layer is the white hardshell which is attached via a layer of velcro, which may cause you to think it can detach easily. Trust me, there’s so much velcro that even trying to detach it on purpose is extremely difficult.
I’ve tried these out on hot long uphill cross country climbs and felt the breathability was good, nor did they bother me. After awhile you forget they’re even there, although they are excessive if that’s all your doing is basic lightweight trail riding (for that I recommend the G-Form knee pads).
Sliding down factor
On the sliding down factor, I found this was minimal. Even under long stretches of pedaling they would stay in place.
I’ve had a few minor crashes at the bike park, and they provide tank level armor. Not really much more to say than that.
You’ll find these on the net for about $80, a worthy investment as that’s far cheaper than the $2,000 emergency room bill I got from that earlier crash.