X5 towing experience and fuel economy

[bfeng]

Originally Posted by Slow&Steady

Ebay has them. I got mine last week form a dealer in Maryland. I wish my dealer only charged $100 bucks.. They charge a min $150 for anything now.. needless to say they own the only 2 bmw dealerships around me. I still have to have it done regardless, but seriously I'm sure it takes them 15 min to do it.

Ah, thanks. I paid $470 from a reliable long time supplier. Best price I found from a dealer was also $470. Nice work getting it for $409.

Fwiw I think many good BMW-focused independents have coding software.
You do not have to go to the dealer

[Thecastle]

Originally Posted by Slow&Steady

That makes more sense that the shift pattern changes when it's hooked up to a trailer.
I'm sure the trans shift patterns have been mapped for the best combination of hp/tq for towing.
Thanks for all the info!!

I would mention that the transmission mapping in tow/haul mode is not very good. I run my car in manual mode for several reasons. I have a 2008 4.8i BTW, generally towing a ~5000lbs travel trailer as loaded.

1) My trailer is heavy and the car still starts in 2nd gear, which is fine if you want to creep along, but too tall to move at least close to traffic speeds
2) The transmission has a real tendency to hold on to low gears for what seems like forever once you've reached your cruising speed.
3) The transmission hunts on highways. 6th gear is generally too tall for me to maintain 65-70mph on flat terrain. So I get a slight downgrade it shifts to 6th, level out loose speed and back to 5th. This constant shifting is hard on the transmission.

So I find it best to leave it in 5th for cruising its able to maintain speed on most interstate grades (sometimes needs 4th for hills).

Around town in city traffic below say 45 I find D to be okay, but I've pretty much stopped using drive and just manually shift.

[Thecastle]

So I wanted to give an update on my experiences. I traded my 2008 X5 4.8i in for a 2011 X5M... This weekend I had a chance to do my inagural tow with my 2011 X5M. I took my travel trailer the same as before to Martin Dies JR. State Park in east texas....

So when I did this drive with my 2008 X5 4.8i in November of last year I averaged 7.3mpg round trip. Towing at an average speed of 65-70mph.

This time same trailer, similar weather conditions (temp, wind, maybe more humid). The 2011 X5M averaged 8.2mpg (indicated by computer). So it would seem that even though the EPA rating of the X5M is slightly lower than the 4.8i. The fuel economy while towing is better. The trailer is nearly the same as last year, maybe slightly heavier because of more batteries, but less water. Went the same route at the same speeds (X5M touched 85mph once or twice while passing)

What I can say is that the X5M can tow the trailer in 6th gear (top gear) and rarely has to drop out of 6th on hills. The 4.8i was always in 3rd-5th gear. It could not tow the trailer at 70mph in 6th.

I will also mention that the 4.8i averaged 8.2mpg driving form houston to big bend, so I can't say conclusively that the 4.8i is always worse. But I can say their isn't much difference it would seem in economy between the 4.8i and S63 engines. What I will say though is that the S63 certinally tows in a more relaxed manner staying in top gear and not needing to be manually shifted.

[Bahb7]

Good thread going here, folks. Figured I'd add my experience so far. I have a 2012 X5 xDrive 50i. I installed an Invisihitch/Execuhitch because I was either told, or read somewhere on one of the forums that it has a higher towing capacity than the OEM hitch, however this is not in writing from Invisihitch. As I understand it, the e70 X5 chassis is rated for 6000 lbs in the USA. In most overseas countries its rated for 7700 lbs. It's the same vehicle, but the hitches are different. I believe BMW outsources the hitch design/fabrication to something in-country. Whoever makes the OEM hitches for the USA market either didn't design, or didn't test to the full 7700 lbs (700 lbs tongue weight), but only to the 6000 lbs (600 lbs tongue weight), hence the reduced USA capacity.

I purchased the hitch with the factory OEM wiring harness, and did the install myself. Nothing outlandish if you're the type that knows which end of a screw driver to hold. Install can be done in about 4-5 hrs. I then had it coded for the hitch, along with a few additional features that are handy. The zoom feature on the rear camera is worth its weight in gold.

I regularly tow an open steel trailer with an e46 M3 track car. Trailer, car, and extra wheels/tires are around 5400 lbs. With proper tongue weight, the setup is very stable and easy to drive long distances. The torque of the twin turbo V8 is fantastic and the 8 spd transmission is also great. One of my longer routes is going from the Boston area out to Watkins Glen, about 400 miles each way, with some pretty long hills along the highway. The 50i will pull at 75-85 mph all day long like this. If I'm taking my time with cruise set at 75 mph, I'll get high 12.? mpg, I think I even saw 13.1 mpg once when I was babying it a bit. If I'm running late and pushing closer to 85 mph when traffic allows, I'm closer to low-mid 11.? mpg.

Other options that seem to help.....I have the air suspension, which is nice. I've also recently upgraded to the factory 20" staggered setup wheels/tires. The low profile and stiff sidewall tires definitely help stability a bit. You'd be surprised how well this setup takes the corners while towing.

What I'm learning is that my trailer tires are likely not up to the task of towing at those speeds.....I seem to chew through them like water with the failure mode of a sidewall bubble. Now as a tire goes bad, I'm replacing them with a heavier duty model to see if that solves the problem.

That being said, I've now upgraded to a full racecar without any real windows, per se, so I'm now in the process of upgrading to a 24 ft enclosed aluminum trailer. My rough calculations put the fully loaded weight at around 7400 lbs including, car, tires, tools, fuel jugs, nitrogen bottle, etc. We'll see how this performs once I actually pick up the trailer. When test-towing this trailer, I noticed that extended mirrors are absolutely necessary for the enclosed trailer at 8.5 ft wide. I suspect that the X5 will perform just fine with the new setup, but with lower mpg.

Anyhow, this has been my experience so far.

[andrewwynn]

My ¢¢: I noticed that the tire weight capacity was right near the max rear corner weight and when I inadvertently went over gross weight by about 560# on a trip I was very impressed with the handling. I've also had the car at max weight (about 3 tons) and towed a 1600# trailer. I think I got about 13-14 with the 3.0i in this situation. Just like you mentioned the lower profile tires will give you improved handling, I have run on flat tires that give me 500# per tire more weight capacity and with air suspension I notice almost no difference in handling from 500-1500# load in/on the back (I have a folding trailer hitch rack).

All vehicles are built with a safety margin in the weight capabilities so your logic is sound in my opinion.


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[80stech]

@Bahb7, you might try running the maximum pressure in your trailer tires to get them to last longer.

[Thecastle]

I'll also add a bit of info on trailer tires.

Make sure they are not bias ply tiers on the trailer, they won't hold up against the speed. Most stock trailer tires ST rated are designed for a maximum speed of 65mph. Which is possible reason your getting sidewall bubbles, the tires are degrading because of heat.

https://www.etrailer.com/question-124195.html

Anyway, there are higher speed rated tires available for trailers, that are rated up to 81mph. Of course a popular swap is also to use automotive or truck tires with the right weight capability. Inflation pressure makes a big difference too, you might want to stop your car occasionally and use an infrared thermometer to measure the tire temps to see if they are getting too hot. Typically they should be below ~157F, and begin fail around ~180. But this varies from tire to tire and is only a rule of thumb.

The other thing to watch is UV rot, as this will also cause the tire to fail.

With all of that said, my trailer has tires rated up to 81mph, and I've towed it as fast as ~90mph while passing without issue and a steady 75-80mph without any sidewall bubbles. Trailer weighs about ~5000lbs as loaded.

[snik]

This is a great thread. The woman made me sell my ole 6.0 powerstroke when she got preggo. And I took he opportunity to try my hand at a 4.8iS. I've always loved them and can't afford an X5M at the moment.
Anyway, I've got a OEM hitch sitting in the garage and will hopefully buy a small enclosed trailer soon and start doing more trackdays again.
So I shouldn't be pulling more than 3k lbs.

I just have to do the transmission seals and fluid and hopefully it will be ready to tow.
That ZF 6sp auto tranny is pretty sketchy. I think it's probably the weak link in the tow setup of the E53.


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[kakalika]

I towed a 16 foot enclosed trailer from MN to TX. Trailer weighed about 7400 pounds on a truckstop scale. I use manual shifting when I tow something heavy. Averaged 16 and above mpg on the trip. Diesel and rear air suspension.

[andrewwynn]

Did you weigh all axles separately and do you recall the weights?

When I've been "loaded for bear" (gross weight 6600#) I usually lose about 100# per front tire. I'm curious if you know the tongue weight and what the difference in the rear axle weight (I usually do a before & after with my heavy duty loads) especially since it's only like $2 vs $12 for a re-weigh


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