NO, I wouldn't do it. Maybe if I was towing a small 2000 lb jetski trailer, but I wouldn't tow anything more than that.

You said you'd be towing your other car, approx 3600 lbs. I'm assuming it's the ZX? By the time you rent or borrow a trailer, load the car on there, and add other stuff in the car as you stated, i'm willing to bet you'll be closer to 5,000 or 5,500 lbs. Your car alone is likely close to 3500. A rented uhaul car trailer is 1900 lbs! Or a steel car trailer with dual axles is 1500+.

I pull a really light weight aluminum car trailer (960 lbs) with a gutted 911 track car (2500), then throw spare wheels and tires on the tire rack (350 lbs), fill the box on the tongue with tools and parts (250 lbs) and my very light car and trailer tip the scales at between 4100 and 4300 lbs. and I carry 500 lbs tongue weight. I know the weights because I've put it on a set of scales to measure both tongue and total towed weight. With all the forces exerted on my hitch while travelling 500-900 miles at a time for events, and and in cornering situations, there's no way I'd trust an aftermarket hitch that relies on a bumper and some holes drilled in sheetmetal to stay together. I installed my factory hitch myself and know the engineering that went into it. As I recall- 14 bolts fasten the hitch the the strongest structure of the car.

Keep in mind that even if you load your car on the trailer and can confirm just 300-400 lbs of tongue weight, the actual peak loads on that hitch when the rear of the truck hits a dip in the road or under extreme braking will be significantly higher than the static tongue weight. I've read a study (from Da'Lan I think) that says that under certain extremes, the actual tongue weight can equal the total towed weight.

All that aside, and at the risk of sounding like I'm going against my own advice, how far do you have to tow with your move? And is this a one time deal? If the move isn't really far ( multi state) then you might get away with it. But for $485, I would think you could rent a uhaul truck and trailer and avoid the risk to your X5 altogether.

OK, I'll get off my soapbox now.

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'04 E53, 4.4 Sport
'97 E39 528i
'86 911 Carrera, track car
'96 BMW R1100R