Bar (Pressure Unit)
The most widely used pressure unit in hydraulics. 1 bar equals exactly 100 kilopascals, approximately 14.5 psi, and roughly atmospheric pressure at sea level. Operating pressures of mobile equipment typically fall in the 150-350 bar range.
Instead of memorizing unit conversions, keeping three references in mind is enough:
- 1 bar = 100 kPa = 0.1 MPa ≈ 14.5 psi.
- 1 bar means 10 newtons, that is about 1 kilogram of force, applied to 1 cm² of area. This is the most practical way to do a cylinder force calculation in your head: bar multiplied by cm² directly gives the order of magnitude in kgf.
- Catalog values are generally gauge pressure, that is pressure above atmosphere; when absolute pressure is needed, 1 bar is added.
Pressure shows how much force the system can produce; what determines speed is flow rate. If a machine cannot lift the load you look at pressure, if it lifts slowly you look at the flow side. The relief valve setting determines the ceiling of the system and is typically kept 10-20% above the highest pressure the load requires.
Electronic retrofit kits do not touch the hydraulic circuit; system pressure belongs to the vehicle and does not change when the kit is installed. Driving the lever more precisely does not increase force, it only improves control.
Where this term is used: How Are Manual Hydraulic Levers Controlled Remotely? A Comparison of 6 Methods