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Load charts are lying about cable wrap and nobody cares
Had a boom truck tip over near Toledo last month. Everyone says the load chart is gospel. I found out the hard way it's not when you add a jib offset. The chart says 4,200 lbs at this radius but the actual lift felt sketchy at 3,800. Weighed the concrete blocks after. Real weight was 4,010. Checked the fine print in the manual from 2011. The chart assumed a bare drum, no extra cable layers. My cable had 3 wraps more than standard. That's a 5% difference nobody mentions. Anyone else ever caught a spec that didn't match real site conditions?
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adam4141mo ago
The "bare drum" thing bit me too, ran a 28 ton boom truck on a foundation job and the chart numbers kept not matching what the truck felt like. Turned out my drum had 40 feet more cable spooled on than the test setup, which adds weight out at the boom tip every time you swing. We figured maybe 150 to 200 lbs of extra effective load, which doesn't sound like much until you're already pushing 85 percent of the chart. Now I count wraps before I trust any number and keep the manual in the cab, because that fine print is where the real limits hide.
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