Here’s the differentiating factor between the S and X; the engineers who designed and built them say the X is capable of towing 5000lbs and the S is not.If you can tell us what exactly is different in Model X that gives it the 5000lb towing capacity the whole community will be grateful to you‚ because nobody seems to have a definitive answer on that.
Not really. According to EU standard the vendor had to show extensive test result with the target vehicle and the product was finally approved for use with Model S.
Not sure where you are finding this relationship between gross vehicle weight and its towing capacity. I don't find this a sound argument and this is why. The towing capacity you mentioned may be true for F250 but lookup the specs for F150. F150 weighs 5900lbs (barely 200lbs more than my Model S) but has a towing capacity of 14000lbs. On the same token Model X is also only 400lb heavier for the same battery size and has a 5000lb towing capacity. The vehicle weight is relevant to towing only in relation to the tongue weight (or vertical pressure on the hitch) and that weight along with all passenger and luggage shouldn't exceed the gross weight or GVWR.
The following factors impact towing:
Engine/Transmission (drive train)‚ engine cooling (or battery cooling if I want to draw a parallel)‚ chassis/structure‚ suspension‚ breaking. As far as I could find‚ dual motor Model S is identical to Model X in all these categories. Please tell us if you are aware of anything different.