"US only" max vertical load for Model X OEM trailer hitch

[steampowered]

I noticed the placard on the side of the 2022 (refresh) Model X trailer hitch has a vertical load limit of 121 lbs, but this limit applies to the "US only".

Why is this restriction only inside the US? Why bother to put "US only" on this restriction? It seems to me the laws of physics should apply equally across all nations on this planet. This leads me to believe the restriction may be more of a regulatory issue than an actual load limit issue.

After all, the tongue weight is 500 lbs while pulling a 5000 lbs trailer. How could a 200 lb bike rack be over the "US only" limit?

 

[bpjod]

The answer is leverage. The 500 lbs rating is for the load directly on the ball whereas the 121 lbs rating is for "vertical loads of up to 120 lbs (54 kg) when the load is cantilevered rearward within 24 inches (63 cm) of the hitch receiver, such as when carrying bikes on an accessory rack".

Hopefully this link takes you to the correct page in the Model X manual where I pulled that quote from.

 

[domodan]

Interesting that it must be within 24 inches. I’ve never measured how far my bike rack hangs when it has all 4 trays on it but it’s more than 24 inches.

I also wonder why the weight limit only applies in the US. There must be a tolerance and if the US regulatory is more strict that every where else, what’s the weight limit everywhere else?

 

[bpjod]

While not explicitly stated in the manual, I presume they're talking about how much rotational force it can withstand at 24" behind the hitch ball. So if the centre of mass were further away from the vehicle you could still use the rack, but the weight of bike(s) + rack would have to be less. Not only does moving the centre of mass further back increase the amount of torque proportional to the distance moved further back, but also it magnifies the torque applied to the hitch mechanism whenever the rack is bouncing as a result of travelling over uneven roads.

I'm personally looking at selling my very heavy tray rack for this rack, or something similar. That way all the bikes are up close to the vehicle - I bet even with all four racks loaded the centre of mass will be closer than 24" behind the ball. Also the NSR 4 bike rack weighs about 20 lbs less than the 2 bike configuration of my current rack, then when I add the additional 2 bike rack extension, I'm almost at the weight allowance before I even mount a single bike!

As for the US only, it looks like (if I'm reading correctly) the rack can ONLY be used for towing (i.e. not even carry any bikes at all) in Australia. Other jurisdictions will have their own restrictions, or none, and there may be different stickers applied or the manual may have different instructions.

 

[Wratran]

Factory hitch added up to 160lbs