I spend as little time on roads as possible. No commuting. VERY little road riding.
I do have a loop around my home town that I do a few times a week, but where I live there is very little traffic.
My knees have been surprisingly well when biking. A few times I found myself about to hit a climb in the wrong gear and chose to hammer through it and had no issues with my knees. Surprisingly. I did have a Hyaluronic Gel shot a few weeks ago and though that hurt like all get-out the first few days after, it's been a lot better know.
That said, hammering a climb on a bike can't compare to a long steep drop while backpacking. The combination of repeated extension + sudden jolt of stopping is brutal on knees.
I struggled at Glacier National Park about two years ago on those long downs. We're talking 3,300 of down elevation (and up!) and going down every step hurt my knees. The good thing is last time we went about a year ago my knees were much better. Love Glacier.
I hope the best for you and those knees. Ride on!
