The load chart on my old Grove was 20% off and nobody flagged it

I was going through a 1989 Grove RT740 manual I picked up at an auction last month, just for reference. The load chart in the cab matched the one in that manual, but when I checked it against the newer Grove charts online, the old one was showing 20% more capacity at certain radii. That means someone ran that crane for years with numbers that were flat out wrong. I called a rigging engineer buddy of mine, and he said it's not that rare with old cranes that got re-certified without updating the charts. Has anyone else caught a bad load chart on an older machine, and what did you do about it?

2 comments

2 Comments

diana6171mo ago

Wait, you're telling me the load chart in the cab was just flat out wrong and nobody caught it for years? That's terrifying. I mean, that's the one thing you should be able to trust on a crane, the whole reason you're not tipping over or snapping a boom. 20% is a huge margin, that's not some small rounding error, that's a whole different machine's worth of capacity. Any operator worth their salt would have felt that kind of difference on a pick, the rigging would feel sketchy way before you hit the limit. And the fact that it got re-certified without anyone checking the chart against the actual machine, that's just a failure on multiple levels. Someone could have gotten killed, that's not a paperwork issue, that's a life or death mistake.

sean_cooper581mo ago

Figure out what year that chart was actually printed first before you assume it's wrong. Grove made a lot of changes between 1989 and the newer online charts, and some of those updates came with revised ratings based on real world testing. A 20% gap at certain radii can be legit if the older machine had different tires, outriggers, or counterweight options that got swapped over the years.