I'm sure this has been asked and answered, but for the life of me I can't locate the answer. How much does the factory hardtop weigh? I saw the specs for the 73-75, I'm talking about the heavy one, 76+. I'm guessing about 350 lbs?
I think we've all put on a few lbs over the last 25 years. I know I have.I weighed my '81 half top about 25 years ago, and it was 188 lbs.
I weighed my '81 half top about 25 years ago, and it was 188 lbs.
Where he has the line pulled back to the winch gives a 2:1 advantage, but that is behind the scale. Without a complex setup (that nobody would create by accident), the only mechanical advantage you would see is 2:1, 3:1, etc. This would make a 200lb top weight 100, 67, etc. The error comes from friction in the pulleys and the extra weight of the ropes, hooks, etc. Some of that would be answered by making the same measurement with the top not there. The calibration of the scale is also a factor.Actually, I think I'm going to take issue with that weight. From the looks of it, it's coming from a top suspended via four pulleys....meaning the some of the vertical force is being transferred to the pulley's mounting screws. After reading the whole thread, it doesn't look like the question ever got answered for sure. I'd say 213 is pretty close, judging by what it felt like on my back. One of you physics guys will have to chime in on this...does having the pulleys in there make the amount of force used to lift it less? If there was only one pulley at each corner, there would be no mechanical advantage. But the fact that there's a pulley at the end and the line is anchored back to the winch, I think there's going to be a mechanical advantage. Sort of like using a snatch block.
Am I right? It's been a long time since I had any physics instruction....But it seems there's an extra pulley in there that would give you a mechanical advantage.
First off, that qualifies you more than enough, your physics is for real, not in a lab. And what you said makes sense. The weight is correct, the extra pulley doesn't factor in until after the dynometer. So the winch is seeing half that load due to the extra pulley. And the added friction and rigging weight probably makes up the extra poundage over the 188 that the bathroom scale measured., in addition to all of the scales being calibrated differently.Couldn’t really tell everything involved with the pulleys from those picks but it looked like the dynometer is in line and not to be effected by the multiple parts of line and/or pulley setup between it and the winch - although the angles will effect the load that the winch sees.
I am by no means any sort of a physics intellect but just a crane operator/instructor with heavy rigging background.
If the rigging from the gauge to the top only has ( from horizontal ) 90* angles that is still only a multiplied factor of “1” so no free help or hindrance from any load angle factors at play.
I can vouch that it's in the 200lbs range, I have carried it myself a few times and even lifted it up and set it on the k5.First off, that qualifies you more than enough, your physics is for real, not in a lab. And what you said makes sense. The weight is correct, the extra pulley doesn't factor in until after the dynometer. So the winch is seeing half that load due to the extra pulley. And the added friction and rigging weight probably makes up the extra poundage over the 188 that the bathroom scale measured., in addition to all of the scales being calibrated differently.
That's the heaviest 200 lbs I've ever picked up is all I'm going to say!