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Old 03-20-2016, 09:48 PM   #29
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Originally Posted by dhoover1027 View Post
-- snip -- I saw the rear tires had become bald on the inside shoulder. -- snip -- Would not do it with the runflats, -- snip -- Too stiff a sidewall. Too much heat generation. -- snip --
DHoover - We have 20K on our run flats and they are not showing uneven wear or excessive heat build up. The only problem with the BMW as a tow vehicle is that it is not embraced by BMW for that purpose and therefore, requires significant investigation to define and implement a stable and safe setup. You will note that BMW also does not embrace the off road world.

Have to admit, not sure why run flat stiff sidewalls and light truck stiff sidewalls would not be similar solutions to add towing stability. Might be a good discussion for the tire engineers. Pat
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Old 03-20-2016, 11:57 PM   #30
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I am not saying the runflats are a bed passenger tire. I have put a lot of miles on them myself.
I'm saying they are not a tire I'd like to tow with with the addition of tongue weight compressing the rear suspension. Which changes the contact patch, overall spring and rebound rates and chamber. They have been engineered (and you will see a star on the side wall) specifically for that BMW. And in the operating environment based on BMW specs.
I agree they do not embrace the off road world. But it's not marketed to replace a Jeep Wrangler.
Have you been towing your AS with it ?
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Old 03-21-2016, 12:10 AM   #31
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My experience with several BMW vehicles over the past few decades (and with two of them towing, an X5 and an X3) is that premature wear on the inner part of the rear tires is not particularly related to camber, but is very related to too much toe in on the rears. With excess toe, the tires scrub constantly, and with wider tires such as 20's they can wear very quickly. Camber gets (wrongly) blamed because people can see it from the rear. They just can't see the toe in as easily.

Adjust the toe to the minimum of the BMW spec for your vehicle. Not just into the (too wide of a) range they spec, but to the minimum of it. Works wonders.

As to additional tongue load impacting rear tires, it is always worth checking that you are within designed axle loads, and tire load ratings. With those two in mind, and correct inflation pressures, I wouldn't worry about the rear tires any more than without a trailer, as you will be within the BMW design spec.

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Old 03-21-2016, 12:17 AM   #32
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Dhoover, I think the tires are the last issue I may expect when towing with my X5. I believe that good alignment makes a lot of difference. In order to get as much as possible from tires on X5 you need to get toe to minimum (0.00 - 0.02).

Re runflats – I do not believe in advantages of having runflat, so as soon as I am ready to change the tires, I will be changing to no runflats. Regardless, I do not understand why towing with runflats would be worse than with non runflats… I am new to towing, but I think that lower profile should be better than higher profile, stiffer sidewalls would be better than softer…

BTW, runflats may be repaired… unless the nail is too close to the sidewall… like regular tires. It is only BMW saying that you cannot repair. Of course, if you drive longer distance without pressure, there could be internal damage and I would not put this tire back on the car.

There is another user of this forum towing 8,000 lbs 31 feet AS trailer with BMW X5 E53. I think a good hitch (Hensley or Propride) is minimizing potential issues of short wheelbase.

I will check how my setup works. Bottom line is that I am not going to drive a truck. I would change the trailer, if my setup does not work. The next TV will be Mercedes GL or BMW X7 (will see in 2018 what BMW has to offer).
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Old 03-21-2016, 12:56 AM   #33
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Dhoover - We have over 16K miles towing Glimmer with Bimmer. The contact patch is addressed with correct tire inflation pressure and the air suspension maintains correct ride height. We have not had the problems you describe. Pat
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Old 03-21-2016, 07:59 AM   #34
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To the OP: It seems everything (tow rating, hitch rating, GVWR, axle ratings, and short wheelbase TV) points to a mismatch between your TV and trailer. If I may, I'm going to suggest something to you.

Rent a whitebox trailer for a few days. In the Norhteast, you can rent them for $120 a day (not a huge investment). Pick a camper thats within your vehicle's manufacturer ratings (6000# trailer weight, 600# tongue weight). Pick a shorter camper (say, 27 ft not 34 ft you plan to tow). Go for a short camping trip to assess your TV's abilities. Pick a road that that has some inclines/declines. Assess the pulling/stopping ability of your BMW. Drive in a windy stretch of the road to get an idea of the stability of the combo.

After the trip, assess your BMW and decide whether its a match to tow a much heavier, much longer trailer. FYI, anyone can hitch up their TV to a monster trailer in their driveway, post a photo to an online forum, and brag about their TV. Nothing replaces a real world test.
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Old 03-21-2016, 10:45 PM   #35
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I have noticed that BMW is using the same payload across all X5s.



The suspension is basically the same in 35i, 35d and 50i, and there is 300 lbs difference between the approved gross vehicle weight between 35i and 50i.
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Old 03-22-2016, 01:16 AM   #36
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Air forums will never provide consistent, experienced advice on setting up this combo. Contact the hitching experts at Can-Am Airstream in London, Ontario who have specialized in this work for over 40 years.

They especially like the towing qualities of the X5. They also especially like the towing qualities of Airstreams, but you're heading in a different direction. They have experience there as well and can help you.
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Old 03-22-2016, 08:39 AM   #37
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Thanks Doug. I was in contact with Andy and reinforced the hitch according to his advice. It just too far from California, but I would go there without hesitation to get everything ready for towing.
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Old 03-22-2016, 10:11 AM   #38
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Took my 2007 Mercedes ML320 CDI to CanAm in October of 2012 to have the factory installed receiver reinforced and while there they also pre-bent and shortened the Hensley Arrow stinger. Dropped by again on the way back from the East coast dealer to fine tune the Hensley with the 23D. Andy really knows his stuff and his employees are a joy to be around.
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Old 03-22-2016, 12:45 PM   #39
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Bono - A common payload rating makes sense from an engineering perspective. The drivers for a different engine choice are fuel economy, performance, and initial purchase price. By keeping payload the same, that is one parameter which is not confusing to the purchaser, contributes to the precision of German engineering, and slightly reduces the sea of BMW option choices. Noting the differences in axle capacity leads one to the possibility that each of the models is configured with specific components based on performance and weight parameters. After all BMW does build "The Ultimate Driving Machine".

Unfortunately, what is missing is a clear indicator that the vehicle is over designed for the marketed capacities. The positive is that the chassis is a refinement of prior models and there is experience which indicates an absence of problems on any of the X5 models when used for towing. Your experience may vary, but you have certainly done considerable due diligence to establish the best configuration for your rig.

Remember that a conservative approach, active driving, and actual towing experience are also required to achieve a safe towing experience. The steering is quite sensitive on the F15, so take care not to over correct if you feel a wiggle from a passing vehicle. Also note that the cruise control on the F15 activates the brakes when the rig is over the speed setting. Normally that is a good thing, but in a down hill section the cruise control rides the brakes, which is not a good thing. So go active and control your descents.

When you get the rig, travel safe. Until then, keep learning. It all helps. Pat
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Old 03-22-2016, 02:58 PM   #40
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switz, thanks. I will ask Andy whether they can fine tune ProPride stinger for me.

PKI - I am not engineer maybe therefore the same payload across all X5 s does not make sense for me... apart from making this easy for BMW to print the same stickers with the payload. I checked a few suspension components for different engine versions are they appear to be the same. Therefore, IMO 35i should have 300 lbs higher payload than 50i.

I have E70, not F15 and the light steering on F15 is one of the reasons
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Old 03-22-2016, 05:10 PM   #41
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Bono - my apology. Please, ignore the F15 specific suggestions.
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Old 12-05-2017, 12:35 PM   #42
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Finally, after over one year, I managed to visit CAT scale with my trailer. After slight dial in the car is:

- max on my front axle (within the tires limits)
- 300 lbs over the limit on the rear axle (within the tires limits)
- 500 lbs over approved GVW

My tongue weight was 940 lbs distributed 100 lbs to the front axle and 180 lbs to trailer axles.

I had one additional adult, dog and spare tire on board. I can decrease the tongue weight by 100 lbs easily as I had some luggage in the front of the trailer. After some shuffling, I can get the combo within the axle limits, probably 200-300 lbs over the payload.

For what it’s worth, the combo is super stable. I towed it for over 8k miles, including a drive from Indiana to California. No problem with power, the only “issue” was with a slight sag in the back – I installed spring inserts and problem solved.

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