Pin Clearance for Front Mounted Hydraulic Cylinders

Telescopic cylinders on dump trucks are the norm, which is rightfully so, given that these types of cylinders offer an exceptionally long stroke from a compact unit. If a dump truck is extra large and carrying a heavy load the telescopic reach will offer a reliable solution.

However, when mounting a telescopic hydraulic cylinder on the front of a dump truck it is important to consider mounting pin clearance. This pin clearance is the space between the pin and the pin hole. Allowing for this gives the body of the cylinder extra room to sway slightly while dumping, while avoiding a side load on the cylinder. A side load occurs when an external force, such as a heavy load in the case of a dump truck, pushes the rod to the up, down, or side. The longer the cylinder stroke and the further the rod extends the more chance of the hydraulic cylinder suffering from a side load.

When calculating pin mounting clearance, the cylinder plunger or one of the sleeves should be extended to a minimum of 1/4” when the dump body is in the down position. The cylinder should be allowed to float in the pin mountings.

Follow the guidelines in the table below to allow for sufficient pin mounting clearance.

Mounting Eye Measurement Suggested Clearance between pin & pin hole
Single Less than 5″ wide 1/16″ to 1/8″
Single Greater than 5″ wide 1/8″ to 3/16″
Double Less than 5″ wide 1/8″ to 1/4″ per side
Double Greater than 5″ wide 1/4″ to 1/2″ per side

We work frequently with customers in the dump truck industry and educate them on pin mounting clearance. Give us a call today to see how we can help you select the right hydraulic cylinder for your business. Give us a call at 1-888-771-1894.