Lift at Pins
The lift capacity value measured directly above the lower link pins. For the same tractor, the value measured at a certain distance behind the pins is lower, because the load lengthens the lever arm. When the two values are confused, the tractor's capacity is thought to be higher than it is.
Lift capacity is not a force but a force-distance relationship. When the load is directly above the pins the moment arm is at its shortest; as the load is moved backwards the same hydraulic force has to work against a larger moment and the weight that can be lifted falls.
- If you see two values in a catalogue, always check which is at the pins and which is at the rearward point.
- When choosing an implement, look not at the value at the pins but at the value corresponding to the implement's real centre of gravity.
- The same implement is lifted more easily if it can be attached further forward.
This distinction is also meaningful for a retrofit kit user: the kit lets you raise and lower the linkage electronically, it does not change the lift limit. If the linkage struggles with a heavy implement, the problem is not in the control but in the load being far from the pins or in the tractor's own capacity.
The context where this term is used: Converting a tractor hydraulic lever to electronic control