Porsche Cayenne, VW Touareg, Audi Q7 owners

[BayouBiker]

A lay person new to towing and not trained in suspension and feedback control systems can do all the research they want and will be hard pressed to find accurate specific information for their situation in a form they can use.

But by posting a particular setup and recommending one does research you have implied that you have done the necessary research and have found the setup in the photo to be competent and safe for US road conditions. However if the research were easy to come by, you would have included the relevant info when you posted the photo of the BMW 7 series sedan towing what looks to be a 27' Airstream. You would have provided the sway critical speed, the null input sway damping factor at 70 mph, and the understeer gradient at .4 g at highway speeds. At the very least, you would have assured the viewer that the pictured setup was inherently stable for the full range of likely conditions expected on US highways. Truth is you can't provide that information because 1) it is not easy to come by, and 2) that setup is not inherently stable for the likely range of US highway conditions.

Edit: For what it's worth. Volvo engineers claim the 2008 Volvo V70 has a maximum towing capacity of 3307 lbs and with a curb weight of only 3527 lbs , 111 inch wheelbase and 235 hp engine it's easy to see why it has a low maximum.

[bono]

I was "a person new to towing and not trained in suspension and feedback control systems" over four years ago. I am not engineer. I did the research and drove from California to Indiana to pick up the trailer, which you claim is dangerous to tow with X5. I towed it since 20k towing miles. If I listened to people like you, I would not leave the house. Maybe it is good to have naysayers like you around. I was scared a bit when I was picking up the trailer... until I started towing. It tows great, despite information from your "model". Thanks to "experts like you", who claimed that my setup would be dangerous on the roads, my research took hundreds of hours and I learnt a lot, before I even started towing.

"posting a particular setup"? Yes, I believe that the setup on the photo is "competent and safe for US road conditions.". I am sorry, but I trust experts who are doing this for living, not self claimed wizards using computer to calculate this or that.

[BayouBiker]

It's easy for me to decide which experts to trust. The engineers who design and test the vehicles then set the manufacturer guidance are far more qualified to know the vehicle stability limits than a trailer and hitch technician and seller. You will find that my guidance aligns very closely with the manufacturers engineering guidance. Coincidence? I can assure you it is not. I find it fascinating that you trust the vehicle manufacturers engineering team enough with your life that you would purchase and drive one of their vehicles but then label them incompetent when it comes to setting a towing limit. When you call people like me incompetent you are casting the manufacturers engineers in the same lot. You have even fabricated a just so story as to why these manufacturer's engineering teams are wrong presumably to complete the lie.

Also there is a distinction between assigning a measured and known risk and labeling something dangerous. I described the setup pictured as risky, not dangerous. The fact that you have beaten the odds thus far is not much consolation in my mind. You personally have mitigated much of the risk with your Propride hitch and slow travel speeds, but many new towers will miss those important factors.

Edit: Another word about towing control stability models. The models do not predict or forecast that a particular setup will drive poorly or feel unsure. An X5 will not suddenly feel like a 1965 Oldsmobile Vista Cruiser when you add a trailer and I have never implied it would. It will instead retain most of its original characteristics. The stability models indicate if the system is inherently stable or unstable in particular scenarios at US highway speeds. Most people will never experience the emergency scenarios used in the models and will therefore never know if their setup is inherently stable and will respond to driver input and self correct or if it is inherently unstable and will careen out of control despite the drivers best efforts. The fact that most people report excellent towing experience is irrelevant to the discussion of stability.

[bono]

Your guidance aligns very closely with the manufacturers engineering guidance? BMW does not test their cars with weight distribution hitches. What exactly are you comparing? This is the gap where people who have actual experience may chime in.

You may be preaching how unstable X5 could be. I just hope that people who are interested in using this car as a towing vehicle will also hear other people like me who may say how things are actually working. Otherwise I would stop even responding, because it does not make much sense to discuss any further.

[Hamish]

Originally Posted by bono

Your guidance aligns very closely with the manufacturers engineering guidance? BMW does not test their cars with weight distribution hitches. What exactly are you comparing? This is the gap where people who have actual experience may chime in.

You may be preaching how unstable X5 could be. I just hope that people who are interested in using this car as a towing vehicle will also hear other people like me who may say how things are actually working. Otherwise I would stop even responding, because it does not make much sense to discuss any further.

I agree with you Bono. We towed our 28’ Eddie Bauer initially with a VW Touareg TDI, then an F150 (5.0 litre), and now a MB GLE350d. The truck was interesting. Gave us more storage for stuff we don’t always use but made parking in tight quarters more difficult. The SUVs give us better daily driver use, much better mileage and make driving down the highway a pleasure. The torque available beats the F150 hands down. With a WD hitch the package is very stable. By the way, both SUVs weigh about the same as the new lightweight F150s so the truck has no benefit if that is one of the points of contention. The SUVs also benefit by having the hitch point closer to the rear axle this providing better stability.

My recommendation is to talk to the folks at CanAm RV in London Ontario, and some others who have used SUVs, cars and trucks to tow their trailer. Once You are personally comfortable the. You can decide. Even better, if you know someone try towing with them to guide you in their vehicle. We did that with a Chrysler 300 and a 30 foot Airstream. Actually my wife did as she used to drive ten tons. She said she didn’t even know the trailer was there.

The SUVs have a lower center of gravity, often better brakes and are quite capable of pulling your small Airstream without difficulty. As to being new to towing so was I with the VW. Being cautious at all times is not a negative with the extra weight, longer stopping distance etc. Five years and 15000 miles later we have never had cause to worry, other than a slow leak in a tire.

The only complaint is lack of storage space, but that’s managed through more thorough vetting of needs vs wants.

[Hamish]

our rig in northern Ontario. 1000 miles from home.

[BayouBiker]

bono, I get that your setup tows beautifully. I have always agreed it would.... unless you get into a sticky situation and then it won't.

Edit: It's a blindspot many people like you and Hamish get into. You think that because your setup does so well under nominal conditions, it has to do even better if conditions deteriorate. Unfortunately, it is not the way the towing physics works.

[Hamish]

Originally Posted by Imdakine1

I’ve got a 2014 Audi Q5 TDI and was looking at AS 22 and 23 but realize the 4,400lbs towing capacity likely won’t be enough.

While I like the Audi Q7 I’m hoping to get the smallest SUV with good towing capacity and am now considering BMW X5 (5,952 lbs) or Mercedes Benz GLE or GLS that have 7,700lbs and the Land Rover Discovery 8,201lbs towing capacity.

I’d assume all should be able to do an AS 22 or 23?

My wife and I have a toddler and we’ve not spent much time looking at towing AS as we studied Airstream and other coaches but now realize no coaches seem to be suited for car seats which we will need to use for a while.

Any advice or opinions on a small yet high enough towing capacity?

To be honest I’m a wagon guy so would have loved the Volvo V90 Crosscountry, the Audi AllRoad A6 version coming back to US market or the Mercedes Benz E class wagons but appears wagons can’t tow that much!

Hi...if you search for posts by cory_can you may find his descriptions of towing with a Q5 TDI. I think he had a bigger airstream. Eventually he moved to a truck simply for storage space with multiple kids, bikes and dogs.

[bono]

Do you care to respond to my question what exactly are you comparing, i.e. your "model" results with engineers results and these align? I am super curious whether you have access to some secret data from BMW engineers.

Originally Posted by BayouBiker

bono, I get that your setup tows beautifully. I have always agreed it would.... unless you get into a sticky situation and then it won't.

[BayouBiker]

Originally Posted by Hamish

Hi...if you search for posts by cory_can you may find his descriptions of towing with a Q5 TDI. I think he had a bigger airstream. Eventually he moved to a truck simply for storage space with multiple kids, bikes and dogs.

Just because it can be done does not make it wise or safe. I can tow a 34' Airstream with my dads '62 Cadillac. Will you now recommend that?

[jcl]

Originally Posted by BayouBiker

It's easy for me to decide which experts to trust. The engineers who design and test the vehicles then set the manufacturer guidance are far more qualified to know the vehicle stability limits than a trailer and hitch technician and seller. You will find that my guidance aligns very closely with the manufacturers engineering guidance. Coincidence? I can assure you it is not. I find it fascinating that you trust the vehicle manufacturers engineering team enough with your life that you would purchase and drive one of their vehicles but then label them incompetent when it comes to setting a towing limit....

The fatal flaw in your logic is that you take the absence of proof as proof of absence. When reading your posts I often think about the distinction between science and engineering. You seem weighted towards the science, not the engineering approach. Real world results should influence your position IMO.

Said another way, you assume that the recommendation for a certain towing rating is proof that a higher rating is not possible or safe. That isn’t how automotive product development, testing, and validation works. If the marketing dept request for a specific rating is met, there is no reason to test a higher capacity to see if it fails. That would be wasteful. Even if the validation team says “we can give you another 25% at no cost” and isn’t told to sit down and be quiet, the purchasing team will voice their thoughts on how that will cost them in another area. And that is before the warranty department chimes in about projected warranty claims and failure rates. Not that those will necessarily be higher, but that they hadn’t considered it yet. When a marketing dept requests a certain tow rating for another reason, eg 3500 lbs because that is a common receiver classification, or 3500 kg because more than that has licensing cost implications, it should be a clue. There is potentially nothing in the vehicle design that precludes a higher rating, except the cost of testing, and possibly some small vehicle improvements. Things like a stronger receiver.

There are lots of other clues available as to the validity of the assumption that the rating represents some type of engineering maximum. Let’s say a vehicle has a 4950 lb tow rating, and a 495 lb maximum tongue rating. 10%. Convenient. Ok. Which do you think is the actual maximum possible of those two separate numbers? Is it just coincidence? Does the vehicle hit the rear axle load rating, the receiver strength rating, and the power train tow rating all at the same time? That is some mighty fine engineering. Great optimization. No wasted transmission cooling, or braking capability, or receiver steel cost.

With pickups, tow ratings are pushed higher due to perceived marketing advantages. So much so that the SAE had to come up with a test protocol to stem the tow rating arms race claims that were going on.

But with other vehicles, the biggest driver is usually cost. Cost of designing, testing, purchasing, and manufacturing. A lower receiver rating is always cheaper. It often isn’t more complicated than that.

When you were asked for proof of failure for manufacturer towing tests beyond published two ratings, you said the proof was the rating itself. This is simply not good enough; if there was a record of a vehicle passing tests at x rating, and failing at y, that would be useful info and would add to the discussion. Lacking such proof, a manufacturer rating is simply an indication of how high a load the manufacturer has tested the vehicle to. Not of the ultimate capability. And certainly not of some perceived instability limit.

The proper manufacturer engineering response to “what if I tow at x over the rating?” is usually “We don’t know, we didn’t test that”, not “the understeer gradient indicates higher risk”

But if you have test results that show that the published tow rating limits for a specific vehicle represent an absolute maximum, by all means provide them.

Don’t get me started on “the manufacturer’s engineers know best about towing” Engineers in Europe will not know about WD impacts. But we do have experts here he do. When you disparage them it says more about you than them.

[BayouBiker]

Originally Posted by bono

Do you care to respond to my question what exactly are you comparing, i.e. your "model" results with engineers results and these align? I am super curious whether you have access to some secret data from BMW engineers.

This question was asked and answered months ago. I have access to some proprietary 2016-17 X5 towing test data along with public domain skid pad data. The primary issue X5 and similar vehicles experience is oversteer leading to uncontrollable jackknife when towing American travel trailers over 6300 lb. WD aids with axle load limits and improves ride quality but it makes oversteer instability worse. All I can advise is watch your speed and your following distance.

[jcl]

Originally Posted by BayouBiker

This question was asked and answered months ago. I have access to some proprietary 2016-17 X5 towing test data along with public domain skid pad data. The primary issue X5 and similar vehicles experience is oversteer leading to uncontrollable jackknife when towing American travel trailers over 6300 lb. WD aids with axle load limits and improves ride quality but it makes oversteer instability worse. All I can advise is watch your speed and your following distance.

I think it may have been that same thread where you were asked, with respect to your concerns about oversteer, what the effects of different factory tire options including staggered tires, active suspension, active steering, and WD settings, were. I don’t recall a direct answer, simply that none of those were considered. This despite the usual expectation that they would have significant impact.

[BayouBiker]

Originally Posted by jcl

The fatal flaw in your logic is that you take the absence of proof as proof of absence. When reading your posts I often think about the distinction between science and engineering. You seem weighted towards the science, not the engineering approach. Real world results should influence your position IMO.

That's just it, I do use real world results. But stability test are not based on the nominal driving experience you, bono and others report. They are based on the extremes that you and bono never attempt or experience. They are the extremes similar to those people here very infrequently describe as the "perfect storm" where their X5 towing a 28' Globetrotter went violently out of control and totaled. You and bono ignore them or chalk them up to driver error. The manufacturers often test for these conditions and sometimes use them to set limits.

I'm not sure what experts you think I am disparaging. Who exactly are they and what scientific and technical training do they have? I am generally complimentary of anyone with certified physics, math and engineering qualifications.

[BayouBiker]

Originally Posted by jcl

I think it may have been that same thread where you were asked, with respect to your concerns about oversteer, what the effects of different factory tire options including staggered tires, active suspension, active steering, and WD settings, were. I don’t recall a direct answer, simply that none of those were considered. This despite the usual expectation that they would have significant impact.

It was a trick question on your part. I responded that I did not have data on the different options and therefore did not consider them, particularly since those on this forum don't provide the specifics of what tires and pressures they run, what their alignment setting are and so forth. I then commented that with respect to towing stability the differences are not significant with the exception of active rear steering, but my model does not accommodate that.

[BayouBiker]

One other point I will make is about the manufacturers use of 10% tongue weight. It is a slimy engineering trick to game the max limit number. They know they need to pass the industry established stability criteria, they also know the most stable trailer has its weight concentrated close to the axle, but they are also aware the legal team needs to avoid lawsuits so they use the industry minimum standard of 10% tongue weight and then carefully configure a trailer with weight distribution similar to a travel or utility trailer but is most stable at 10%. Fortunately most campers don't buck these limits..... Oh except those who hitch up European SUV's to trailers that are too big.

[Tamarack]

I trust the manufacturer’s experts! 😊

[AlbertF]

Originally Posted by BayouBiker

A lay person new to towing and not trained in suspension and feedback control systems can do all the research they want and will be hard pressed to find accurate specific information for their situation in a form they can use.

But by posting a particular setup and recommending one does research you have implied that you have done the necessary research and have found the setup in the photo to be competent and safe for US road conditions. However if the research were easy to come by, you would have included the relevant info when you posted the photo of the BMW 7 series sedan towing what looks to be a 27' Airstream. You would have provided the sway critical speed, the null input sway damping factor at 70 mph, and the understeer gradient at .4 g at highway speeds. At the very least, you would have assured the viewer that the pictured setup was inherently stable for the full range of likely conditions expected on US highways. Truth is you can't provide that information because 1) it is not easy to come by, and 2) that setup is not inherently stable for the likely range of US highway conditions.

Edit: For what it's worth. Volvo engineers claim the 2008 Volvo V70 has a maximum towing capacity of 3307 lbs and with a curb weight of only 3527 lbs , 111 inch wheelbase and 235 hp engine it's easy to see why it has a low maximum.

The EU tow rating is 1800 kg - 3960 lbs. The XC90 with the same engine (with the same transmission and overall gearing - the final drive is shortened to offset the taller tires) is recommended for 5000 lbs in North America, despite being considerably heavier than the V70.

I’m happy with the combination. Power is decent, stability is very good, ride is excellent, and the wagon body provides excellent utility.

My old 2001 S60 would have felt more stable at highway speeds, but ride quality deteriorated as the total load approached GVWR. I towed a 1975 Overlander with that car - over 20000 miles worth. I have previously documented my experiences on this forum.

My experience has taught me that towing ratings are only a small part of the equation. Weight is only a minor factor in safe towing, and hitch setup is probably the most significant.

[BayouBiker]

Originally Posted by AlbertF

The EU tow rating is 1800 kg - 3960 lbs. The XC90 with the same engine (with the same transmission and overall gearing - the final drive is shortened to offset the taller tires) is recommended for 5000 lbs in North America, despite being considerably heavier than the V70.

I’m happy with the combination. Power is decent, stability is very good, ride is excellent, and the wagon body provides excellent utility.

My old 2001 S60 would have felt more stable at highway speeds, but ride quality deteriorated as the total load approached GVWR. I towed a 1975 Overlander with that car - over 20000 miles worth. I have previously documented my experiences on this forum.

My experience has taught me that towing ratings are only a small part of the equation. Weight is only a minor factor in safe towing, and hitch setup is probably the most significant.

One of the downsides of experience without a technical lens from which to view it can correctly inform some aspects but nearly always misinforms on the most critical concealed issues.

For example setup is the most important aspect for comfort and handling feel and ride quality and your experience has confirmed that. Speed and inertial moments (mass and its relative distribution) are the most important factors in safe towing where safety is defined as the ability to avoid events that could cause catastrophic damage and injury, so your experience has misinformed you about weight. Towing ratings are the single best and easiest way for the lay person to understand if their setup will be safe and stable on the roadways for which the rating was set because the manufacturer has done the hard work of boiling the complexity down into easy to understand and measure limits. Again your experience had misinformed you.

You are using the word stable to mean that your setup rides nice and feels comfortable, and again your perspective is wrong. Towing stability does not refer to performance while puttering gently down the road. It addresses emergency situations at the far extremes of expected road conditions and whether or not the setup when confronted with these extremes is inherently stable and will respond to driver or vehicle control input, or if the setup is unstable and will go out of control no matter what the driver or vehicle computer does.

Finally it is improper to use European towing limits for US made trailers on US highways. I addressed this previously. I guess you missed that point. You are towing somewhere just at or under 5000 lb with a vehicle the manufacturer suggests is only safe to tow 3300 and you don't understand the basics of what it means to have a safe and stable setup. This is very risky should you need to rely on the vehicle in a genuine emergency.

[ARF]

Happy to share my experience (not opinions).

We have been towing our 2017 27FB since mid-2016 with our 2015 Audi Q5TDI. We bought our AS from Can-Am and they set up our Q5 with a custom hitch ball assembly, WD, and anti-sway bars.

We full-timed for a year, traveling all around the US, and now live in Summit County, CO. We have towed well over 30K miles in a variety of weather conditions, and over numerous passes. Living here in the High Rockies, we have to cross the Continental Divide (sometimes 2-3 times) just to go anywhere.

With proper planning and precautions, we have never felt unsafe. If there are bad road conditions due to inclement weather, we re-route or wait until conditions improve. We go down passes at the same speed we go up. If there are high winds, we slow down.

There are some things we have to sacrifice:
- In order to lower hitch weight, we do not carry a spare TT tire. We upgraded to the Michelin XT tires and have never had a flat.
- We go up steep passes at about 45 mph, so add about 10-15 minutes to our daily travel time.
- The Q5 has lower ground clearance than a larger SUV or pickup, so this limits our ability to get to some off-road boondock sites.
- We store our bikes (sometimes two singles and a tandem) in the trailer and/or on the roof of the car.
- We don't carry a generator - but once I upgrade to Lithium batteries, saving about 60 lbs, we can put a generator on the A-frame. Can-Am developed and installed a nifty locking mount for the Honda generator that sits on top of our battery box.

WARNING - this is a suggestion - but not an opinion: You might want to consider starting out towing with your Q5 since you already own it. If you are uncomfortable, then get a TV that makes you more comfortable.

Happy to share more experience with you. Just direct message me.