Reducing Wobbling on a Thule Excursion Roof Top Box

Question:

I have a 91 incch Thule Excursion roof top box that wobbles in front. It is too long and not supported well in front. Cross bars fit ok. What is the appropriate max. Length for a roof top box on a 2014 4 Runner?

asked by: Stuart W

Helpful Expert Reply:

There are a few things that you can do to ensure a fit, and approach the wobble of your existing box without making a purchase.

First, you'll want to make sure that your crossbar kit is spread out as far as the mounting system or crossbars will allow. This will give the roof box a better platform to rest on while driving, and reduce its wobble.

Next, when you load the roof box, you'll want to make sure that less of the weight is put into the front of the box, and put more into the middle of the box. Ideally, you'll have 25% of the weight in the front of the box, 50% of the weight in the middle, and the remaining 25% of the weight in the rear. You may need to adjust slightly to make this fit.

Another option is to ensure that the bolts underneath the box where it mounts to your crossbar are tightened down. A good tip when doing this is to alternate knobs as you tighten down, and make sure that all knobs receive the same number of turns. Being loose or unevenly tight on one carriage set can make the entire box ride loosely, even if the rest of the box is installed correctly.

Finally, you can verify a measurement of your vehicle to make sure that you have a compatible box, and to figure out how to best mount your box. Measure from the center of the mounting holes you are currently using on the box to the end of the box. This gives you the minimum clearance of the vehicle.

Then, measure from the center of your front crossbar to the line where your rear hatch meets the roof. This is your available clearance.

If your minimum clearance from the box is less than your available clearance, your box is a good fit. If the minimum clearance is more than your available clearance, then you don't have a good fit and have one of two choices:

Use the box, but set it further back on the vehicle to where it interferes with the operation of the rear hatch. This lets you keep the box but makes it hard to use your rear cargo space. It also risks damage to the cargo box and your hatch if you open the hatch quickly.

Or, outright replace the box by buying a new box that matches the available clearance. If you have the factory crossbars, you'll want to pick up the Thule Sidekick, part # TH78GC. This box uses a similar mounting system to your existing box, but only requires 36 inches of clearance to properly fit your vehicle.