I know your concern, believe me! I had laid my bike down by tilting it over too far while moving it one day in the driveway and I couldn't pick it up by myself! I had to get help. Afterwards when I would put the bike on the Jiffy stand I would watch the bike move a little bit and I would freak out. I would think " Oh no! It's gonna fall over again".
I even posed on this forum about my uneasyness with the bike falling over. I remember reading Smitty's thread that the Jiffy stand, and I quote "Is a work of art". Well, I didn't believe him ( at first )
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But then I started raising my bike up on a lift and you want to worry about it falling over, try for the first time lowering it on a lift!! My heart was in my mouth when it came down for the first time and rocked ever so slightly front to back. But it
didn't fall over! One time the bike came down faster than usual and I thought for sure it's gonna fall over then, but it didn't! Now I have complete confidence in that stand. I just now watched the video that Smitty had a link to and there's a guy
jumping up and down on the bike while it's on the stand. I mean, what does it take to make it fall over?
Just make sure it's in gear on an incline. It won't fall over, it'll just walk away from ya!! :s