Re: slamschwinnburrito/ now with big pics !!
Spring rates explained: As per Rock Shok's website 350lbs, 400lbs, 450lbs, 500lbs, 550lbs, 600lbs, 650lbs, 700lbs, and 750lbs. These are rates per inch of travel and most all bike shock springs are designed only for about 2-3 inches of travel before total compression. The trick is your not taking into to consideration the other factors involved with suspension design, such as mechanical advantage, shock incline angle, swingarm to shock travel ratio, or the original intended use for the shock. (All these things can be figured out by searching google for "Spring rate calculator" for motorcycles or bikes)
A better quality shock such as one made from Rock Shok can be had for as little as $100 and are very adjustable and can be had with the many different spring rates listed above. The cheap Chinese made $10 no name shocks are really just "po-go" sticks, zero adjustment, zero or flat out minimal damping and who knows what the spring rate is. You'd be much better off using cheap Chinese shock to suspend your seat and make the frame a rigid than what you've done here.
Also are you a midget? Have you even taken a minute to measure the distance between the seat and the potential BB position? I guess comfort is not a factor on your design but I know I couldn't fit on this thing, my legs would be a pretzel trying to pedal. Listen I'm not trying to bust you nuts here I'm just trying to give you some "Constructive Criticism" and maybe a little knowledge to make your next bike even better than your last. Someone once told me that if you don't take the time to learn from your mistakes you're destine to keep repeating them over and over and over.
I'm planning on a chapter in my "bike builders book" I writing that will explain in detail all aspects of bike frame and suspension design.
But dude seriously you need to do some cleaning in there, build some shelves, burn some trash, paint the walls white, a workbench would help you tons!
Later Travis