Question for BMW X5 owners

[PKI]

The Invisihitch is reported by their reps to be a runner up in the BMW vendor competition. It is actually a well designed cross member and weldment. With a custom receiver, it could be the basis of a good bolt on hitch solution.

I have never inspected the E70 hitch, so no opinion. The Curt we installed seems to work at 6000/600 loading. We have about 15K on it so far with no problems.

The torque arm reinforcement is an improvement that would make the F15 a much more capable tow vehicle. Too bad there is not an engineering team with the capability to develop a kit that could be bolted in place to reinforced attachment points similar to the ones used to mount the rear axle carrier. There is, of course, a concern that modification could have the potential to degrade the rear crumple zone. However, an impact break away design for the reinforcement attachment, which would provide the transfer of vertical force, while not yielding to the forward horizontal forces of an excessive impact, seems possible. Lots to think about.

[bono]

Also as a side note Invisihitch is rated to 7,700 / 600 lbs, i.e. to BMW X5 full towing capacity. It is a shame that it was proven that it does not work with WD.

[PKI]

Originally Posted by bono

Also as a side note Invisihitch is rated to 7,700 / 600 lbs, i.e. to BMW X5 full towing capacity. It is a shame that it was proven that it does not work with WD.

The rating of 7700lb tow capacity is not of much use with a 600lb tongue weight constraint. And that brings us back to reinforcement. The question remains how. Looking forward to hearing your experience with the upgrade. Pat

[bono]

... unless you tow a boat...

I am not an engineer, so I do not understand all the matters in relation to the reinforcement. My understanding is that it prevents the receiver from bending and that is the main purpose of the reinforcement. I do not know how much it would increase the tongue weight limit, if at all. I believe there is some safety margin built in. So, if BMW says that the car can handle 600 lbs, probably it can handle more. There are people who use X5 to tow the trailers with 800 lbs-1000 lbs tongue weight. There is one E53 without reinforcement and a couple of E70 with reinforcement.

My tongue weight with ProPride hitch will be in 800-900 lbs range.

[PKI]

Edit prior post

Originally Posted by PKI

-- snip -- while not yielding to the forward horizontal forces of an excessive impact, seems possible. -- snip.

I incorrectly stated this. It should read "while yielding to the forward horizontal forces of an excessive impact, seems possible." My apology for the error.

Pat

[switz]

CanAm told me that the Mercedes factory receiver on my 2007 ML320 CDI diesel (which had been re-welded by a factory recall in 2008) needed to be reinforced to properly handle the torque that is applied to the vehicle with weight distribution hitches.

There is a photo of what they did in my "images" link below the avatar. They had to drop the air tank for the air suspension and re install it below their bar.

The ML towed a new empty 2013 25FB International Serenity to Phoenix from Los Angles and crossed the CAT scales with only me in the car and got passing numbers on the axle and GVW loads. There was adequate power for the climb out of Palm Springs on I-10 east bound. The 833 pound Airstream literature tongue weight was 1,150 pounds with the Hensley hitch attached and full propane tanks.

The wife and I loaded the trailer with our "stuff" and both of us went to the CAT scales again. The car was not as happy with the trailer weighing 6,800 pounds and the axle ratings and GVW of the ML were exceeded. Being new to the whole towing scene, I found a 2012 Ram 2500HD with Cummins and the weight issues were solved.

I went to get the 23D on the East coast and towed it back to Phoenix with the ML. I stopped by CanAm to have them go over the Hensley hitch installation (same one as used on the 25FB) and they tack welded the lift arm brackets to the trailer frame. After a stop at A&P Vintage Trailer Works in Paradise, TX for some modifications, I towed the trailer on to Phoenix through some steep mountain descents into the Salt River Canyon south of Show Low, AZ.

Driving the posted 35 mph, the small diesel had enough back pressure to control the speed downhill without the brakes.

I think the ML and the 23D are a good match. I would not desire to tow our 31' Classic with my ML.

A more modestly sized Airstream should be no issue if the X-5 is setup properly and towed at reasonable speeds on the flats and significantly reduced speeds during mountain descents.

The ML has a front axle load bias (little payload even empty) with no one in the car, so adjusting for that to keep from exceeding the front GAWR can be a challenge. I would think that would also be the case for the X-5 since the diesel engine is heavier than their gasoline power plants.

The CAT scales will let the X-5 owner know if his numbers are appropriate. If so, then we all hope the welded supports in both the ML and the X-5 do their job properly with no hidden damge to the cars.