recumbent, knee trouble

i posted a thread before and someone responded but i guess i wasn't clear about what i'm looking for. i ride a recumbent and i do not clip into pedals. Someone on this forum said something about homemade fiberglass wood shims and i'd like more details on this. Or... any other pertinent information, like modifications i can do with my seat position or distance from the pedals. I'm having alot of trouble because my bike is my main transportation and the thought of giving it up makes me bummed, yet my knees are crying out for a change. thanks.

 

I used to ride a recumbent and I tried to stay the lead group up the hills. Start spinning more in a lighter gear and it won't matter what pedals you use. This will take time. You can't mash the gears and be a happy bent rider