So I have one more question/concern about my bike (1985 Miyata Ridgerunner). I measured the frame and it seems to be an 18 inch frame. I am 5'11. Everywhere I look it says that I need about a 22 inch frame or 56 cm road bike or anywhere from 18 to 21 inch mountain bike depending on my inseam length (which I think is 30 inches based on my jeans).
I also read that when adjusting the seat you should be able to almost fully extend your leg with your heel on the pedal (let's call this criteria 1). If you are able to do this by adjusting the seat height, does the frame size matter? Also, you are supposed to be able to touch the ground with the tip of your feet while seated (let's call this criteria 2).
The reason I ask is because it seems like the bike I have is too small for me, but I'm not sure because I can't quite reconcile all these adjustment criteria. I've maxed out the seat height. Currently, I am able to sit comfortable and just touch the ground with the tip of my feet, but at the same time my knee is pretty bent when I put my heels on the pedal. I must be missing something...
I was wondering if I could just get a taller seat (if such a thing exists) that would allow my legs to be almost fully extended when I have my heels on the pedal. Then again, if I make my seat any higher in order to meet criteria 1, I will not be able to meet criteria 2... I'm confused... and I don't want to hurt myself biking... What gives?!