X5 35d -- serious tow vehicle w/ a split personality?

[FunfDreisig]

Is anyone using their X5 35d to haul a trailer (5,000-6,000 lbs.) ? If so are you happy?

Back ground:
Our 2001 X5 4.4i (E53) was totaled last week* and we are in the market for a replacement. We live in the Texas Hill Country and used our X5 as our serious tow vehicle. Our little 5x9 trailer with electric brakes is rated at 5,000 lbs. We regularly hauled a couple of tons of limestone, gravel, road base, etc. with this rig.

Now we would like to find a more economical (read fuel efficient) alternative without giving up the X5's nicer features

Funf Dreisig

* The X5 was rear ended by a pickup at 60MPH as my wife slowed to turn right off of a 2 lane ranch road -- OUCH ! My wife is OK The X5 is now an organ donor

[Weasel]

With the amount of low end torque it has I'd imagine it to be a solid step up from the E53 4.4i (rip).

I actually installed an E70 trailer hitch toady at work, easy if you did the E53 install. The thing with the retrofit programming is the E70 platform has alot higher software integration level than the E53/E46/E39 etc. and usually requires a decent sized software update to the rest of the vehicle. But when we install a hitch at the dealer we charge the labor for install but the retrofit programming is covered by warranty... so that shouldn't be a problem. Just be prepared to leave the vehicle at the dealer for a day while the programming is done. (loaner car time)

[FunfDreisig]

Originally Posted by Weasel

With the amount of low end torque it has I'd imagine it to be a solid step up from the E53 4.4i (rip). ...

That is my hope

We had been looking at the X5 35d as a possible replacement "down the road" but the road got a lot shorter all of a sudden Now I'm having to make a few quick decisions, just to have a vehicle with A/C*, let alone one that can haul 6,000 lbs of limestone in serious comfort.

Hopefully some one can tell me -- they've done it and they love it

Funf Dreisig

* The "ranch truck" doesn't even have a radio -- so A/C would be a serious luxury

[vinuneuro]

I don't see why it wouldn't be much better than your 4.4i. If it handles as well as the E53's do when towing, the 35d will be about as perfect a tow vehicle that exists for reasonable loads.

[Fraser]

It will kill the 4.4i on fuel use alone.

[Weasel]

I can't really think of any aspect that wouldn't be at least as good... it even has a 100/1000 lbs higher rating than the E53.

I'd be willing to say, just by looking at the design/engineering of it, that it would be the best tow vehicle BMW has made up to date.

[FunfDreisig]

Thanks for the feedback folks. I agree that the X5 35d should be a great tow vehicle -- I just haven't seen anyone posting that they have actually used an X5 35d for serious hauling I like being on the leading edge but not the bleeding edge, hence the OP.

FWIW I recently test drove a MB ML320 BlueTec diesel and a X5 35d on two consecutive days. There are significant differences but I'll focus on the comparison for towing....

* The ML has a heavier tow capacity (ML 7,200 lbs vs X5 6,000 lbs) despite the X5's higher HP and Torque

* The ML hitch is a $ 530 factory installed option, instead of a $1,000ish dealer installed add on which requires you to "Remove and discard" the metal part of the original bumper.

Then there is this disclaimer in the X5 trailer hitch Installation Instructions.... " BMW NA does not supply or have an approved electrical brake controller for the Trailer Hitch (Tow Bar) Kit." . IIRC you need some form of aux brakes for any trailer above 1,600 or so lbs. So, does this mean that X5s are only able to handle 6,000 lbs when the trailer has hydraulic brakes (e.g. mechanically actuated by forward pressure on the tongue)?

I'm beginning to wonder whether BMW actually designed/intends for E70 X5's to be used for serious towing.

Funf Dreisig

[JCL]

Originally Posted by FunfDreisig

Then there is this disclaimer in the X5 trailer hitch Installation Instructions.... " BMW NA does not supply or have an approved electrical brake controller for the Trailer Hitch (Tow Bar) Kit." . IIRC you need some form of aux brakes for any trailer above 1,600 or so lbs. So, does this mean that X5s are only able to handle 6,000 lbs when the trailer has hydraulic brakes (e.g. mechanically actuated by forward pressure on the tongue)?

I'm beginning to wonder whether BMW actually designed/intends for E70 X5's to be used for serious towing.

Funf Dreisig

Yes, the limit is 1600 lbs for a trailer without brakes. The simplest way is to have a trailer with surge brakes, as you reference. You can certainly add an electric trailer brake controller, it is just that BMW doesn't supply them and doesn't want to be in the business of recommending them.

You are correct in that BMW doesn't want to be in the towing business. They make it possible for owners to tow, but with those owners taking personal responsibility for towing. Adding an electric trailer brake controller is not a big deal, it is a straightforward installation.

There is an interesting question on the suitability of the 35d for towing, as diesels by design generally don't develop much retarding force due to the fact that the throttle is always wide open, unlike a gasoline engine. Any serious diesel used for towing, from a Cummins 5.9 to a Class 7 or Class 8 truck with a Cat, Volvo, or Detroit engine, will have an exhaust brake of some sort installed. That exhaust brake turns the engine into a pump, effectively, working against a resistance. Without it, trucks pulling loads go through brakes too quickly. I would be interested in the experiences of those who have towed with both the 3.0 diesel and a similar BMW gasoline engine, as to whether they notice the difference. I don't know enough about the valve train in the 35d to know whether there is any effective retarding force with the standard engine. Certainly the diesel has the torque for towing, but stopping is an important as going, and I would want to know about the retarding force available before terming a 35d "the ultimate towing vehicle"

[Fraser]

I've towed with lots of turbo diesels (LandCruiser, Range Rover, Merc ML, LR Discovery 3, Jeep Grand Cherokee) as well as my 3.0d and I've never had any issue with engine braking with any of them.

[grover432]

Engine braking is not any more an issue with diesels than gas engines at the weights being contemplated here. A 5,000 lb trailer with electric brakes will be fine behind an X5. The 35d has more than enough torque to get he load moving easily and the electric brakes will stop the trailer without the need for an exhaust brake. If you will be heading downhill allot with a heavy load, an exhaust brake would be of some help, but I don't think most people would need one with a 5,000 lb load.

grover

PS I pulled a 9,000 lb load behind a Dodge 3/4 ton with Cummins and never found the need for more than the electric brakes. Brake overheating is really the only concern, which might make one consider an exhaust brake.