What determines lift capacity?
Lift capacity is not determined by hydraulic pressure alone. Pressure multiplied by cylinder bore gives the raw force; that force is transferred to the hitch end through the linkage geometry. The relief valve setting sets the upper limit, while the tractor's own weight and front axle load set the safe limit.
Four factors together determine lift capacity:
- Pressure × cylinder cross-section: this is the raw force produced by the cylinder. Work is typically done in the 180–220 bar range.
- Linkage geometry: as the force is transferred to the hitch end through the lift links and connecting pins, it changes with the leverage ratio. That is why capacity figures are usually given at two separate points, 'at the pin end' and 'at a certain distance behind the pins'; the exact reference point is stated in your tractor's operator manual.
- Relief valve setting: it limits the highest pressure the system can reach; raising the setting strains the pump, the hoses and the seals.
- Tractor balance: heavy equipment hung at the rear lightens the front axle. The load that can be carried without losing steering control may be lower than what the hydraulics can lift; front ballast is used if needed.
The electronic retrofit kit does not touch any link in this chain. LFT20 and LFT54 move the control lever via the cable; the lifting force comes entirely from the tractor's own hydraulics. The cable pull force figures (10 kg for LFT20, 15 kg for LFT54) are for moving the lever and have nothing to do with implement lift capacity.
Full topic: Converting a tractor hydraulic lever to electronic control