heaviest light without crank stand

[forbyfiev]

I'm going to be using a 70 lb instrument and we won't have crankovators. What's the safe weight limit to run up a couple risers on a Mombo, say with 2 crew?

 

[David W. Jones]

Between 60-90 pounds depending on the build.

Most average around 85 pound rating.

 

[lambert]

Stupid question but what is the main failure with a fixture that’s to heavy for the stand?

 

[rob norton]

Stupid question but what is the main failure with a fixture that’s to heavy for the stand?

At the other end of the handles/knobs that tighten or loosen risers is a screw that pushes a brake pad. The brake pad prevents or allows movement of the riser.

The main failure is most likely just too much weight for the brake pad (pads?) to handle.

Check out the schematic from matthews' replacement parts section (#8 on the right).

I'm sure my explanation pales in comparison to asking a Key Grip or someone who knows more about physics but you should get the idea.