I only see the knees hitting the chest when the OP really crouches down. He does have pretty good flexibility. But, perhaps it isn't an issue for most ordinary riding.
Originally Posted by
Wheever
OP, your seat looks low to me. You have a lot more extension to go before you would have to worry about a straight leg. (Part of that might be the fact that you're peddling very toe-down.)
Originally Posted by
xlbs
2) Raise your saddle a wee bit, and experiment with that as well, based on point # 1.
I agree, I'd try raising the seat a bit. Maybe 1/2", or even 1". I go by the method, heels on the pedals, straighten the leg at bottom of stroke, then adjust from there.
What is the actual crank length on the OP's bike?