is there some sort of mechanical load limit that a cleat can take before it either breaks, or breaks the part of the shoe to which it attaches ? or maybe the pedal ?

SPD-SL looks like it should be able to handle plenty of force on the way down - but on the way up ? could it be broken by pulling up too violently ?

how's the durability of SPD ? to me it looks like it should rip out a chunk of the shoe in no time. i don't really understand how so much force can be transferred to such a tiny piece of plastic on shoe bottom. maybe if the shoe was made out of steel

also do SPDs feel stable ? do they wobble around and squeak or screech as you pedal ?

after days of deliberation i am no closer to deciding on SPD vs SP-SL. my other thread answered the logistics questions for me - both SPD and SPD-SL passed that one.

but i still need to make a choice. so now i need to analyze the mechanical angle.

thanks in advance.