Pneumatic Cylinder Bore and Stroke Explained

Bore and stroke are two of the main dimensions used to describe a pneumatic cylinder.

The bore affects the force the cylinder can produce. The stroke defines the distance the piston and piston rod can travel.

What is pneumatic cylinder bore?

The bore is the internal diameter of the cylinder barrel. It is also the diameter of the piston surface on which the compressed air acts.

A larger bore provides a greater piston area. At the same air pressure, a larger-bore cylinder can therefore produce more theoretical force than a smaller-bore cylinder.

Browse pneumatic cylinders by bore size.

What is pneumatic cylinder stroke?

The stroke is the distance travelled by the piston between its two end positions. On a conventional cylinder, this is also the distance travelled by the piston rod.

The stroke is not:

• The overall length of the cylinder
• The exposed length of the piston rod
• The distance between the mounting points
• The total length of the cylinder when extended

Browse pneumatic cylinders by stroke length.

How bore affects force

The force produced by a pneumatic cylinder depends primarily on the effective piston area and the air pressure acting against it.

Increasing the bore increases the piston area and therefore increases the available force. Actual working force is lower than the theoretical figure because of seal friction, pressure losses, machine resistance and other operating conditions.

Extension force and retraction force

On a double acting cylinder, extension force is normally greater than retraction force.

During retraction, the piston rod occupies part of the piston area. This reduces the effective area available for the compressed air to act against.

Where similar force is required in both directions, the rod-side force must be included in the cylinder selection.

How stroke affects the installation

A longer stroke increases the required movement but also affects:

• Overall cylinder length
• Available machine space
• Piston rod stability
• Load guidance
• Potential side loading
• Air consumption
• Cycle time

For long movements where machine length is limited, a rodless pneumatic cylinder may provide a more compact solution.

Does the same bore and stroke mean the same cylinder?

No. Two cylinders can have the same bore and stroke while differing in:

• Body construction
• Overall length
• Mounting dimensions
• Piston rod thread
• Port size
• Cushioning
• Sensor compatibility
• Operating standard

Always use the manufacturer part number and dimensional drawing where possible.

Standard and special sizes

Cylinder Warehouse lists common bore and stroke combinations across multiple manufacturers. Larger, non-standard or configured requirements can be submitted through the Request a Quote page.

For practical measurement guidance, read how to measure pneumatic cylinder bore and stroke.