Mounting Pelican 1550 cases to a Happy-Trail SU Rack using some parts from the Happy-Trail pannier mounting kit.

Each Pelican 1550 case has a volume of about 34.7 liters, providing a combined volume of nearly 70 liters. The cases are advertised as "indescructible" and have stood up to quite a beating in the past. Each case will also float in salt water with 70lbs of gear and is completely air- and water-tight.

The mounting kit contains the following parts:

I did not use their "pucks" to screw into the rack, instead I used a 3/8" by 2" pin from the local hardware store:

I drilled out one of the top-center holes in the rack with a 3/8" bit (which just takes the powder coat off), then stuck the pin through from the back and secured it. There's also a nylon spacer and an o-ring. When the case is mounted, the o-ring is compressed and provides a good seal.

On the outside of the case lid is the plastic bracket and the hole where the pin fits. The extra bolts on the sides of the hole are to secure a steel plate on the inside.

The bracket is secured with M8x30mm high-strength bolts since the M8 bolts that come with the kit are too short to go through the shell of the pelican case and then seat securely in the bracket. I used the M8 bolts from the kit to secure the steel plate instead.

Here is the steel plate and the inside of the case. The plate is a 1-1/2" wide, 1/8" thick weldable steel plate available from just about any hardware store.

The pin fits through a hole in the plate and is secured with a removable pin.

Chains bolted to the inside of the case take stress off the hinges on the case. The elastic net in the lid keep large flat things held in the lid when the cases are open. The other case has a similar net in the main compartment.

Cases on the bike, seen from the side:

Cases on the bike, seen from the rear: