Are Rooftop Rack Companies Lying to You?

Let’s take a look at what Yakima is saying about racks for use with its own SkyRise tents which have a maximum weight (dynamic load) of 115lbs.

“DO NOT use SkyRise with factory crossbars; they are too flexible.”

“Vehicle AND roof rack system must have a minimum of 165 LB load carrying capacity.”

Source.

Are factory crossbars too flexible?

Doesn’t too flexible mean that it will damage my vehicle? Wouldn’t that only apply to weight-distributed objects that are heavier than the maximum cargo load limit as specified by the manufacturer in the vehicle manual? So if I stay under the maximum cargo limit then why am I still in trouble?

Let’s take an example of a 2019 Land Cruiser which has a rooftop cargo weight limit of 154lbs. Doesn’t that weight limit pretty much mean, by definition, that if I put on the distributed weight of 154lbs or less then that Land Cruiser is NOT going to be damaged? A rooftop tent is certainly distributed weight.

Why am I asking for trouble if I put a SkyRise 3 tent on that vehicle? It only weighs 115lbs and is well under the 154lbs limit.

The rooftop cargo weight limit as specified by the manufacturer is the dynamic load weight limit. That’s the weight limit while the vehicle is in motion and would apply to on/off-road conditions. If you plan to only stay on road during your camping journey then a higher maximum would apply except Toyota won’t tell us what it is.

A problem appears with the static load limit. This is the limit while the vehicle is parked. In our case, that’s when we load up the rooftop tent with lots of people. Generally, you can assume the static load limit is about 4x the dynamic limit. For our 2019 Land Cruiser we can estimate the static load limit to be 4x154lbs or 616lbs. The problem is that we don’t know for sure because the factory won’t tell us. Plus that static load limit includes the weight of the tent (115lbs,) so you can only load up 485lbs into the tent. The maximum load capacity for a SkyRise 3 tent is 600lbs but you’re still limited by that 485lbs rack limit in this case. Two adults would be fine but a third adult would put you over.

How do we solve this rack problem without buying another rack?

You could just mount the SkyRise 3 onto the factory rails, cutting out the crossbars altogether. The factory rails will almost certainly not have a problem. The problem is scratching the rails. Some people have done this without a problem.

You can test your rack crossbars to see if your calculations are correct. In this case, the 4x dynamic load calculation says I should be able to load 485lbs into the tent while parked. Can I? Well, let’s test that by setting up the SkyRise 3 on factory crossbars (on your vehicle) and start adding weight. Add one adult and note the deflection. If no trouble yet, add another adult. How does the deflection look now? Does it look like you could have trouble? It’s the third adult that might land you in trouble. If you’re not sure with two adults then don’t add a third. It’s time to buy a new aftermarket rack.

Another testing option to put a packed rooftop tent on crossbars sitting on blocks of wood. Then start adding adults to the top of the packed tent (sitting.) Note crossbar deflection as you add bodies. Same process as before.

“Vehicle AND roof rack system must have a minimum of 165 LB load carrying capacity.”

4×165=660lbs

If you are going to carry a tent with a maximum load capacity of 600lbs then the vehicle and rack should be able to carry that much. The 165lb limit ensures that. But what happens when your vehicle won’t carry that much, like the 2019 Land Cruiser? You can put a beefier rack on top that raises the limit but you still can’t go over the vehicle limit while driving. If you go over the vehicle limit and end up rolling it while driving then it’s your fault. I think quite a few people go over the vehicle limit and are at risk. In the case of the SkyRise 3, it is well under the vehicle limit so no problem.

Conclusion

It’s not that Yakima is lying it’s that we need more information to understand why it is setting its limits.