The Foldable Hitch has a tongue weight of 500 lbs. Its the Volvo bicycle hitch which is limited to 130 lbs (probably how it is designed). Volvo clarified this on their website.

It is really hard to imagine that 4 bikes plus a rack will put 500 lbs on the tongue. I'm not an engineer, the way I calculate this is: 100 lbs (bike carrier) + 120 lbs (4 heavy bikes) = 220 lbs

This website says to compensate for a cantilevered bike rack by using only 2/3s of the 500 lbs or 333 lbs.

http://www.hitchrider.com/hitch.htm Lots of websites do not even mention calculating for leverage as hitch specs are way lower than full capacity as mandated by some governmental body. It seems that 4 bikes are well within specs. This hitch is well made.

see:

https://accessories.volvocars.com/en-ca/XC90(16-)/Accessories/Document/VCC-516542/2020

I tried to explain this earlier, and apparently wasn’t clear.

You don’t want to do what you did, it won’t lead to the correct answer. The Volvo rule of thumb is probably fine, but I don’t care much for rules of thumb. For anybody who thinks they have a situation that is close to the limit of the specification, here is what you can do:

This hitch rotates into place, and locks. As such, all that matters is the amount of applied torque at the point of rotation; too much torque and the lock breaks down. In the end it is torque, and not linear force, that matters.

The calculation of allowable torque, given the Volvo 500 lb spec limit at the hitch ball, is made by multiplying the applied force at the ball and the distance of the ball from the point of rotation.

Volvo is probably assuming that most owners will be hauling a trailer, using a ball. Tongue/ball arrangements will probably place the ball about one foot from the point of rotation, depending on the length of the tongue that goes into the receiver. So, the Volvo spec is actually based on an allowable torque at the point of rotation of roughly 500 ft-lb (in British engineering units, if you are metric this converts to about 675 Nm.)

Now, you can load whatever you want onto this hitch, so long as the applied torque doesn’t exceed 500 ft-lb. If you are using a bike rack you will probably have a straight shaft/tongue that goes into the receiver.

You can make a simple calculation, to see where you are re. applied torque. What you do is to take the weight of the bike rack that you want to use, and measure the distance from, roughly, the edge of the back bumper to the center point of the weight of the rack. Let’s say that the rack weighs 75 lb and its weight is centered about 2 ft from the bumper. This creates an applied torque of 150 ft-lb at the point of rotation.

Now, you need to add include the torque due to the weight of each of the bicycles and whatever other stuff you hang out there. Let’s say that you have four bicycles, and each bicycle weighs about 30 lb, and they will be located at 1, 2, 3, 4 feet from the bumper. You do the arithmetic and get 30, 60, 90 and 120 ft- lb, respectively. Now you add everything up, 150+30+60+90+120, and you get a total applied torque of 450 ft-lb. Very simple!

You know that Volvo has included a factor of safety in their spec, probably at least a factor of two, so you have no problem at all at 450 ft-lb. As I indicated previously, I have loaded this hitch to 400 ft-lb, traveled long distances, hit many bumps and chuckholes, and had no problem whatsoever.

You say you are not an engineer. I have a couple of degrees in mechanical engineering. The simple calculation I have illustrated above will get you to a safe operating situation.