I picked up an older Thule Adventurer cargo box for $50, with Thule crossbars and feet that won't fit my T4R rack. This thing is a beast, as long as my rig.

I've fixed a couple of cracks with ABS plastic welder, cleaned it up, installed new lift supports and made brackets to mount to the factory crossbars and rack. I didn't want to spend lots of $$$ on new Thule feet to fit the rack, etc.

After some back and forth advice from Thule via email, they suggested the best location to mount such a huge box on a smallish truck and I'm all set. (FYI, it' overhangs the front crossbars by 24", and overhangs the rear by as much too. The lift gate opens just somewhat so with this on, rear offloading will be done via back window)

One remaining challenge... The lock has been pretty wrecked and it now uses a screwdriver to engage. It turns but doesn't lock the lid down. I can lift the lid if I try, after locking it. Like it kind of engages and if I lift it'll "click" and then open, like the locks are slipping open.

Question: Will the lid open at highway speeds if the lock isn't engaged? When the lid is shut, the upper lip closes way past the lower lip, (like completely covers it) so I don't think there is a way for wind to lift it up, but I'm hesitant to take her out for a highway test drive.

Any advice?

Why would you risk such a potentially hazardous situation, if that lid doesn’t lock and you can open with little effort, then you should not drive with it unless you secure it some other way. A ratchet strap would work, but see if the manufacturer has replacement locks. The wind at hi way speeds will likely open it

Yes it can. This is why on later models Thule made it so you can't pull the key out until it fully locks. You might be fine just driving along, but wind gusts can pop that thing open and rip the lid off.

Ratchet straps it is!

get a nice 3 inch wide x 20 foot ratchet strap .. go from under the truck and then to the other side and over the truck.... pull it real tight and make sure the strap rubs against the drive shaft too.. make sure and tighten it down real good.....


that way it can't open and you can't go anywhere either.... so you don't injure any other drivers when your box opens on the highway...

How about some old school CJ style hood latches?

Having been in a vehicle on the highway when the lid blew off a thule box, I can verify that yes, it can happen. I can also verify that almost everything in the box will blow out almost immediately, and either hit other cars, or be hit by other cars. The lock is very important to keeping the box closed, also don't overload the box to the point of deformation. Thule will sell you another lock. I know someone who just bought and installed one and they said it was pretty cheap.

The adventurer boxes are nice cause you can throw snowboards, boots, and other wet equipment in it and keep the interior dry.