How to Choose the Right A10VO Pump Size: 45 vs 71 vs 100 cm³
When you need an A10VO axial piston pump, the displacement (size) is the first thing to get right. This guide explains how to match the 45, 71 and 100 cm³/rev sizes to your machine’s flow requirement, so you can confirm a replacement or spec a new unit with confidence.
Start with the flow your circuit needs
A10VO pumps are variable-displacement swashplate pumps for open circuits: flow is proportional to drive speed and displacement, and the swashplate is adjusted steplessly to vary flow to demand. The size you need is set by the maximum flow your actuator requires:
- Estimate the flow your cylinder or motor needs at working speed (litres per minute).
- Divide by the available drive speed to find the displacement you need — then choose the next standard size up.
- As a rule of thumb, a machine needing roughly 100–120 l/min at around 1500–2200 rpm points to the 71 size; roughly 60–90 l/min points to the 45; over 160–200 l/min points to the 100.
Size comparison at a glance (Series 31)
| Size | Displacement | Max flow (at rated speed) | Rated speed | Approx. weight | Typical machines |
|---|---|---|---|---|---|
| 45 | 45 cm³/rev | ≈ 117 l/min | 2600 rpm | 23.5 kg | Compact excavators/loaders, small presses, auxiliary circuits |
| 71 | 71 cm³/rev | ≈ 156 l/min | 2200 rpm | 35.2 kg | Mid excavators/loaders, injection machines, presses |
| 100 | 100 cm³/rev | ≈ 200 l/min | 2000 rpm | 49.5 kg | Large excavators, heavy machinery, multi-pump circuits |
All sizes share the same 280 bar nominal / 350 bar peak pressure rating (Series 31), so pressure capability does not change with size — what changes is how much oil the pump can deliver.
Common mistakes when picking a size
- “Bigger must be stronger.” Not quite — pressure creates force; displacement creates flow. Size the pump for flow, and check the working pressure separately.
- Ignoring the speed limit. Larger sizes have lower rated speeds (45: 2600, 71: 2200, 100: 2000 rpm). If your drive runs fast, confirm the size is within its permissible range.
- Forgetting real-world efficiency. Calculate with ~90% volumetric efficiency, not the theoretical maximum.
Still unsure?
Send us your machine model, the old pump’s nameplate details, or the model code — we will confirm the correct size and configuration before you order.
