UnderCover Flex Installation- Quick Overview 

Installing your new UnderCover Flex is simple and can be done with one person in less than 30 minutes. It’s state of the art design does not require drilling, and provides a custom tailored finish that fit the precise measurements of your truck bed.

How your FLEX is packaged

Each Flex is built and assembled in the Midwest... The heartland of the USA. Every cover comes preassembled, and packaged with special air-pack bundles ensuring your cover arrives safe, damage free, and ready to be put directly on to your truck.

What is included?

The FLEX requires no drilling, however if your truck has a plastic drop in bed liner there may be some minor trimming required for proper fitment. The only tool needed is a 9/16 wrench or socket. In the box:

  • The FLEX hard folding Tonneau Cover
  • Pre-assembled mounting rails (Driver & Passenger side specific)
  • Hardware Bag
  • Drain Tube (2)
  • A model specific install guide (

Here’s a quick three step process for your UnderCover Flex Instillation.

Attaching The Side Rails

Start by attaching both mounting rails to their specific driver and passenger side bed rail. When the mounting rail is level with the bed rail, tighten the center clamp first to hold the mounting rail in position. Then attach all other clamps to hold the mounting rails in place without over tightening the clamps in case need to readjust them after the cover is placed on the truck.

Mounting the Hard Folding Tonneau Cover

On the underside of the Flex cover there is a track for front two mounting bolts that will need to be in place before placing the cover on the mounting rails. After your cover is mounted, make sure the bulkhead is covered by the front flap to assist with weather protection within the truck bed.

Unfolding the Cover

Once the cover is placed in the mounting position, unfold the cover gently to ensure fit along the bedrails, and over the tailgate. Check the slam latches to be sure that each latch is secured to the mounting rail. Once the cover is located correctly on top of the bed, pull the cover’s release cables (one pull from either side operates both sides) to release each panel from the bedrail, and open the cover to its full up-right locked position to tighten and secure the cover. Once your hold folding cover is tightened and secured, attach your drain tubes to help divert any intruding water away from the bed.