Trial by Fire Completed. GT 27FBT first tow with Cayenne!

[jcl]

Originally Posted by richard5933

Except that some vehicles might be outfitted with heavier axles, tires, or wheels than required. Your assuming that all systems in a vehicle are up to the same level as these components, and it's simply not always true. Brakes, transmissions, cooling systems, and other key components are also involved here. It's even possible to have a rear axle capable of supporting a super high number of pounds and the vehicle's towing capacity is restricted due to the axle ratio. This would not be reflected in the axle ratings.

My Suburban is a great example - heavy duty 3/4-ton rear axle but with a gear ratio which lowers the safe towing limit. One could argue that this is merely a performance issue, but if the axle ratio means that the tow vehicle cannot safely get up to speed or climb the necessary grades that too is a safety issue. It can also lead to a domino effect failure of other components.

I think that I'm looking at this holistically, trying to include the whole vehicle in the towing limitations and that you're looking at a few key systems and assuming that if they're good so are all the other components.

A reminder that are discussing a Cayenne that is towing within its tow rating, is loaded within its tire and axle ratings, and has an OE receiver that wasn’t built to accommodate WD. Reinforce it, problem solved.

Everything else is redirection.

I am not talking about the axle rating applied to that component. I am talking about the vehicle axle rating as determined and tested to by the vehicle manufacturer. Two very different things.

You asked about all the vertical loads on all those components apart from the actual axle and tires. I pointed out that the vehicle tire and axle ratings consider all of those other components already.

Now we are on to cooling systems and brakes. Those are covered by the tow rating. They relate more to longitudinal loads, than vertical loads.

Acceleration is not a safety issue, it is just claimed to be by those who want to justify more hp. For years, HD trucks with 80,000 lb weight ratings had 350-400 hp, eg Cummins 350, Cat 3406B. HP determines acceleration rate.

I really don’t think you are looking at it holistically, you are picking on specific components. The vehicle axle rating I refer to is a holistic rating. The axle manufacturer’s axle component rating isn’t, except to the extent that it considers axles, bearings, housing, etc.

We often see an over reliance (IMO) on ratings as a predictor of safety. Use the example of your 2500 Suburban. Yes, it has a higher GVWR than a newer model. But it was exempted from many safety tests by virtue of that higher GVWR, and it is 15 or 20 years out of date of best practice in terms of occupant safety features. But it has a higher GVWR. Is that enough?

[WellSaid11]

Originally Posted by richard5933

Except that some vehicles might be outfitted with heavier axles, tires, or wheels than required. Your assuming that all systems in a vehicle are up to the same level as these components, and it's simply not always true. Brakes, transmissions, cooling systems, and other key components are also involved here. It's even possible to have a rear axle capable of supporting a super high number of pounds and the vehicle's towing capacity is restricted due to the axle ratio. This would not be reflected in the axle ratings.

My Suburban is a great example - heavy duty 3/4-ton rear axle but with a gear ratio which lowers the safe towing limit. One could argue that this is merely a performance issue, but if the axle ratio means that the tow vehicle cannot safely get up to speed or climb the necessary grades that too is a safety issue. It can also lead to a domino effect failure of other components.

I think that I'm looking at this holistically, trying to include the whole vehicle in the towing limitations and that you're looking at a few key systems and assuming that if they're good so are all the other components.

100% correct by analogy on your Suburban. Simply "knowing" those limits (especially just on one system) is not the key, but not exceeding those limits - including a "modification" limit - in light of the REST of the TV's components, etc. as well is the key.

Originally Posted by jcl

A reminder that are discussing a Cayenne that is towing within its tow rating, is loaded within its tire and axle ratings, and has an OE receiver that wasn’t built to accommodate WD. Reinforce it, problem solved.

Everything else is redirection.

No, what you stated is redirection and the "problem" is not "solved" as you state. If any vehicle has a "rating" of X for a system or component, and you modify it and exceed X because of the modification, then you simply do not know what the point of failure may be on another component that is not designed to support the modified system that is now X plus whatever.

Originally Posted by jcl

I wouldn’t exceed any recommendation without understanding the potential failure points.

Again, not sure how "understanding the potential failure points" would allow you to exceed a recommendation when it comes to something such as your receiver. If Porsche, BMW or any manufacturer states that this is a "Class _ receiver, do/do not use WD....etc." then even with a modification you better be aware of what your allowable use is, what the actual limits are AND then not be exceeding them. Having some margin is preferable, but exceeding the recommended tongue weight is a bad idea no matter what your rationale might be. This is because Porsche, BMW, etc. (or any manufacturer) are also telling you "this is the allowable limit along with the limits of ALL other components as well."

If I buy a TV with a max tow rating of 7700 pounds and my AS has a GVWR of 7600 pounds, I don't care what has been done to the receiver, etc. as I am at a margin that I don't want to be at - underrated numbers or not. The fact that I "know" this does not matter because if I am driving a TV that is not specifically manufactured for towing most of the time, I should also "know" that many other systems were not "primarily" designed for that use. Axles, suspension, no exhaust brake, lack of an integrated factory brake controller, transmission not specced for frequent towing, etc. That is not to mention all the other OEM components that were not "primarily" designed for towing throughout the vehicle. While many vehicles not designed for frequent towing can and do well long term while towing, this still matters.

The Cayenne S and Q7 TDI towed car trailers, travel trailers, utility trailers, toy haulers and flatbeds. The fact that they "could" didn't mean I wanted to keep doing it as the maintenance on both of those cars is not cheap and it certainly wasn't any less cheap or more infrequent with towing. Brake job, suspension components, tires and everything else are expensive on all vehicles, but even more expensive on these vehicles. Even if I had modifications made to my hitch, suspension or something else, used higher load-rated tires or did something else I still knew that there were other components that didn't fit the bill for long-term towing use and a 27' or 28' AS would be pushing it within those margins.

Nobody has to buy a 3/4 or 1 ton diesel to tow any trailer under the sun, but after having been to this rodeo many times it is nice to know you pretty much can tow anything under the sun and not worry "too" much about every little thing when doing it.

I have a Sherline tongue scale, but it collects a fair amount of dust.

YMMV.

[jcl]

Originally Posted by WellSaid11

100% correct by analogy on your Suburban. Simply "knowing" those limits (especially just on one system) is not the key, but not exceeding those limits - including a "modification" limit - in light of the REST of the TV's components, etc. as well is the key.

No, not correct, since the vehicle axle weight rating (assigned by the vehicle manufacturer) is not the same as the axle component rating (as assigned by the axle manufacturer). Two different things. Two otherwise similar vehicles with the same axle component (and corresponding ratings) could have different wheels and number of wheel studs, and so have different vehicle axle ratings.

Originally Posted by WellSaid11

If any vehicle has a "rating" of X for a system or component, and you modify it and exceed X because of the modification, then you simply do not know what the point of failure may be on another component that is not designed to support the modified system that is now X plus whatever.

The component we are discussing modifying is a receiver. It has no moving parts. It is a simple structure. We know that the vehicle can support the higher vertical load as long as we stay within the vehicle axle ratings. The chassis was already designed and tested at the higher load, we are just applying it under the rear floor instead of on top of it. For decades, before the advent of factory hitches, we built custom hitches for each vehicle. It wasn’t complicated.

Originally Posted by WellSaid11

If I buy a TV with a max tow rating of 7700 pounds and my AS has a GVWR of 7600 pounds, I don't care what has been done to the receiver, etc. as I am at a margin that I don't want to be at.

I find this confusing. You are willing to take your trailer to 100% of its rated load but don’t want to take your tow vehicle to a slightly lower %? You trust the trailer manufacturer more than the vehicle manufacturer? If you are willing to go to 80%, just as an example, wouldn’t you apply that safety margin to both the TV and the trailer?

[propchef]

Let's say I lift my Ford (or Chevy) 3/4 ton 3 inches, change the wheels and tires, "upgrade" the brake pads and shocks, and install airbags. Now compare this to the owner of the SUV who does a fairly simple, basic reinforcement of the hitch.

Which vehicle is out of factory spec? Not the SUV.

[waninae39]

Tow ratings are very conservative
ask Andy at canam RV and he'll tell you that they are almost meaningless
here are some of their videos https://www.canamrv.ca/towing-expertise/videos/
some SUV can tow better than some trucks , yet the rating don't show that

IMHO, its better to speak to those in the industry that have years of experience rather that what the OEM marketing numbers show

[jcl]

Originally Posted by propchef

Let's say I lift my Ford (or Chevy) 3/4 ton 3 inches, change the wheels and tires, "upgrade" the brake pads and shocks, and install airbags. Now compare this to the owner of the SUV who does a fairly simple, basic reinforcement of the hitch.

Which vehicle is out of factory spec? Not the SUV.

True.

Now consider a 2500 RAM or GM pickup. The OE receiver flexes. It also rusts and the welds break, but that is an aside. E trailer offers a range of heavier duty receivers from reputable manufacturers, with higher ratings, and each built like a tank. No longer OE. Doesn’t change vehicle capacity or ratings. Better for towing. Smart upgrade. But we aren’t accusing those owners of things like ignoring safety or putting the public at risk. IMO it is exactly like strengthening the receiver on an SUV while still respecting vehicle ratings.

[WellSaid11]

Originally Posted by jcl

No, not correct, since the vehicle axle weight rating (assigned by the vehicle manufacturer) is not the same as the axle component rating (as assigned by the axle manufacturer). Two different things. Two otherwise similar vehicles with the same axle component (and corresponding ratings) could have different wheels and number of wheel studs, and so have different vehicle axle ratings.

Richard is exactly correct as to what what he stated about his Suburban. As you have done many times in this thread and others, you are raising red herrings and engaging in misdirection.

His statement on safely was simple as to his axle issue. You raising GAWR vs. what the axle manufacturer assigns is not the issue he was speaking to.

Originally Posted by jcl

I find this confusing. You are willing to take your trailer to 100% of its rated load but don’t want to take your tow vehicle to a slightly lower %? You trust the trailer manufacturer more than the vehicle manufacturer? If you are willing to go to 80%, just as an example, wouldn’t you apply that safety margin to both the TV and the trailer?

You are confused because I never said anything like that.

Do you even own a trailer? Have you ever towed any type of trailer? Do you own any type of tow vehicle now or have you ever?

You speak about these issues like you read about them in a book.

[jcl]

Originally Posted by WellSaid11

Do you even own a trailer? Have you ever towed any type of trailer? Do you own any type of tow vehicle now or have you ever?

We’re going here again?

Previously responded to.

Not right now.
Yes, for decades.
Yes. An SUV, not surprisingly. Many others over 46 years. Even some trucks.

Perhaps focus on the message, not the messenger.

[WellSaid11]

Originally Posted by propchef

Let's say I lift my Ford (or Chevy) 3/4 ton 3 inches, change the wheels and tires, "upgrade" the brake pads and shocks, and install airbags. Now compare this to the owner of the SUV who does a fairly simple, basic reinforcement of the hitch.

Which vehicle is out of factory spec? Not the SUV.

Both are “out of spec” and nobody implied to the contrary.

Originally Posted by waninae39

Tow ratings are very conservative
ask Andy at canam RV and he'll tell you that they are almost meaningless
here are some of their videos https://www.canamrv.ca/towing-expertise/videos/
some SUV can tow better than some trucks , yet the rating don't show that

IMHO, its better to speak to those in the industry that have years of experience rather that what the OEM marketing numbers show

So the numbers supplied by the manufacturer are to be ignored? Ignore the manufacturer’s guidance on WD or no WD? Tongue weight? GVWR? Towing capacity? Door jamb sticker? GAWR?

That proposal is certain to have some commentary thrown at it.

Originally Posted by jcl

Perhaps focus on the message, not the messenger.

This has been done as to both. Both paths have been endeavors that have been an exercise in futility.

You should buy yourself a trailer and get out on the road. The real thing is way better than the book published 40 years ago.

[foobar]

Hey guys. Time to chill out here.

All relevant ratings for both the trailer and the tow vehicle are being honored, with 'perhaps' one exception.

That one possible exception is the hitch WD rating and that has been reinforced significantly .

Even though the hitch has been reinforced, I will try and get as close as possible to the original spec when outfitting the trailer.

The spec is a moving target however and there are vehicles in the United States with exactly the same configuration, options, model year, etc that were outfitted with an incorrect sticker on the hitch indicating that the hitch tongue weight limit is 660lbs while others say 772lbs. This 660lb value is known to be incorrect and is the sticker for EU regulations for non-WD hitches.

I spoke with Porsche North America and the correct value for the hitch WD limit is the same for all Cayenne generations as the hitch and primary body structure has not changed significantly since the first generation Cayenne. The correct value is 1157lbs for the WD hitch.

However, I have reinforced the hitch (and this is not rocket science) and will try and get the trailer tongue weight as close as possible to the 772lbs sticker on the hitch.

As I stated above, all other tow related parameters are within limits for both the Cayenne and the Airstream.

This might leave some of you uncomfortable. Fair enough, so go ahead and enjoy your more capable tow vehicles.

I am comfortable with my rig. It will perform fine. I am anal and will have a properly loaded TV and TT that is weighed regularly to ensure all limits are met.

Folks need to be more concerned with the idiots I see every day surfing down the road looking like a boat trying to get up on plane. TV front end in the air, ass end dragging the ground. No WD hitch, no sway control and a grossly overloaded or poorly configured tow setup and many of these improper TV's are pickup trucks. It won't be me upside down or running into you because I didn't install a brake controller, it will be one of the yahoos...

Last note: FYI, the Cayenne is specifically designed for towing according to the Porsche engineer I spoke with. Example: The transmission and engine reconfigures itself for towing when a 7 pin connection is made and trailer power is detected.

[richard5933]

Originally Posted by foobar

Hey guys. Time to chill out here.

All relevant ratings for both the trailer and the tow vehicle are being honored, with 'perhaps' one exception.

That one possible exception is the hitch WD rating and that has been reinforced significantly .

Even though the hitch has been reinforced, I will try and get as close as possible to the original spec when outfitting the trailer.....

My comments weren't really aimed directly at you or your setup, and the concern wasn't whether or not someone modifies a hitch like you've done. If done correctly, what you're describing can do as intended, assuming that the hitch was the weak link.

The concern I have is the implication made in the thread by other postings that not exceeding the axle and tire ratings is the only real concern, overriding other component's limitations. You obviously are clear on this, so apologies for distracting from your thread pointing it out for those who will come across this thread later on.

[NWBoondocker]

Originally Posted by foobar

TV front end in the air, ass end dragging the ground. No WD hitch, no sway control and a grossly overloaded or poorly configured tow setup and many of these improper TV's are pickup trucks.

Ya, I see these all the dang time as well. A trailer has to have a very heavy tongue weight indeed to make an F-250's headlights point skyward. It scares me, and I give them a very wide berth. The available friction on the front tires must be microscopic.

Some of them are even going 75+ mph while towing giant stick-built trailers that probably have 65-rated tires.

Most of the time they seem to get away with it, until they don't. Last week, after a long traffic backup, I passed a rollover trailer accident on the freeway. Tow vehicle was an older model Explorer, couldn't see the trailer make since the entire rig was on its side and angled diagonally across two lanes. Trailer was pretty big, but I did not see any sign of a WD hitch as I passed by.

A good WD hitch and careful loading/balancing goes a really long way toward safe operation. Sounds like the OP has taken that to heart.

[gypsydad]

Originally Posted by WellSaid11

Both are “out of spec” and nobody implied to the contrary.




So the numbers supplied by the manufacturer are to be ignored? Ignore the manufacturer’s guidance on WD or no WD? Tongue weight? GVWR? Towing capacity? Door jamb sticker? GAWR?

That proposal is certain to have some commentary thrown at it.




This has been done as to both. Both paths have been endeavors that have been an exercise in futility.

You should buy yourself a trailer and get out on the road. The real thing is way better than the book published 40 years ago.

Hard to do for some folks who troll these type sites, but I agree with you...get an AS and then join the discussion with your experience...

[WellSaid11]

Originally Posted by foobar

Last note: FYI, the Cayenne is specifically designed for towing according to the Porsche engineer I spoke with. Example: The transmission and engine reconfigures itself for towing when a 7 pin connection is made and trailer power is detected.

This is a bit far-fetched. Having owned a Cayenne S and having towed with it, and while it is a great vehicle that tows reasonably well, it most certainly is not "specifically designed for towing." Very similar to the way a 911 Carrera or MB C63 AMGs "can" be tracked and do somewhat well (subjective) - but they still are not "track" cars.

The adaptive transmission and engine adaptations while towing are design elements that assist the Cayenne when towing, but Porsche does not design, build, market and sell a Cayenne specifically for towing. The same goes for all of VAG as to the Q7/Q8, Lambo Urus, Touraeg, etc. MB and BMW on the larger SUVs as well.

I understand what you are saying though, and it will tow well within limits.

[foobar]

Originally Posted by WellSaid11

This is a bit far-fetched. Having owned a Cayenne S and having towed with it, and while it is a great vehicle that tows reasonably well, it most certainly is not "specifically designed for towing." Very similar to the way a 911 Carrera or MB C63 AMGs "can" be tracked and do somewhat well (subjective) - but they still are not "track" cars.

The adaptive transmission and engine adaptations while towing are design elements that assist the Cayenne when towing, but Porsche does not design, build, market and sell a Cayenne specifically for towing. The same goes for all of VAG as to the Q7/Q8, Lambo Urus, Touraeg, etc. MB and BMW on the larger SUVs as well.

I understand what you are saying though, and it will tow well within limits.

We are splitting hairs here. The Cayenne was designed for a number of purposes. Off road capabilities and towing are two of them. These capabilities are not used as often, but are definitely applications that were targeted by the engineers during development.

Early Cayenne advertising shows Cayennes in off road applications and towing. It does not take long to use Google to find a Cayenne towing an Airbus passenger plane.

Was the Cayenne expressly designed only for towing like an 18 wheeler? No.

Were towing capabilities specifically targeted during development of the Cayenne? The answer is yes.

It's not like slapping a tow hitch on a Accord or a Camry. Cayennes were intended to be tow vehicles and during the summers I have spent in Germany I see a lot of Cayennes towing travel trailers and even utility trailers in the more rural areas.

[WellSaid11]

Originally Posted by foobar

We are splitting hairs here. The Cayenne was designed for a number of purposes. Off road capabilities and towing are two of them. These capabilities are not used as often, but are definitely applications that were targeted by the engineers during development.

Early Cayenne advertising shows Cayennes in off road applications and towing. It does not take long to use Google to find a Cayenne towing an Airbus passenger plane.

Was the Cayenne expressly designed only for towing like an 18 wheeler? No.

Were towing capabilities specifically targeted during development of the Cayenne? The answer is yes.

It's not like slapping a tow hitch on a Accord or a Camry. Cayennes were intended to be tow vehicles and during the summers I have spent in Germany I see a lot of Cayennes towing travel trailers and even utility trailers in the more rural areas.

Not really splitting hairs at all. A Cayenne is not "specifically designed for towing" whereas a F-350 really is.

Just sayin'

[Genebuilder]

That Cayenne, with the additional weight welded on to its rear, is now a more a tow vehicle than a road worthy Porsche. Look out for the added oversteer when executing your non trailering “Porsching around”.

[foobar]

Originally Posted by WellSaid11

Not really splitting hairs at all. A Cayenne is not "specifically designed for towing" whereas a F-350 really is.

Just sayin'

Still splitting hairs. Both a Cayenne and F-350 were designed to be used as tow vehicles.

While a Cayenne is designed to satisfy multiple intended uses (including "specifically" towing"), an F-350 is more heavily optimized for load carrying and towing capacities and by design has higher cargo and towing limits.

So we'll have to agree to disagree on splitting hairs

Have fun and thanks for chiming in. Appreciate the input.

[foobar]

Originally Posted by Genebuilder

That Cayenne, with the additional weight welded on to its rear, is now a more a tow vehicle than a road worthy Porsche. Look out for the added oversteer when executing your non trailering “Porsching around”.

Hi Gene, the weight of the additional steel added to reinforce the hitch is around 40 lbs. The change to the Cayenne handling characteristics is pretty much zero when not trailering. "Maybe" a professional race car driver can honestly tell the difference when the overall vehicle with two passengers weighs 5500lbs. Maybe not... but ... I can pretty much guarantee that I won't be able to tell the difference

Let's see ... 40lbs/5500lbs = 0.7% of total mass.

[WellSaid11]

Originally Posted by foobar

Both a Cayenne and F-350 were designed to be used as tow vehicles.

and

Originally Posted by foobar

While a Cayenne is designed to satisfy multiple intended uses

are far different statements than your earlier statement of the Cayenne being "specifically designed for towing" - your words.

Nothing to disagree on here. Vehicles "specifically designed for towing" generally don't leave the factory without an integrated brake controller or with a hitch that needs to be modified and/or strengthened and many other aspects that are addressed.

The Cayenne was simply not "specifically designed for towing" as you said, but rather was "designed to satisfy multiple intended uses" (as you later said) and one of those would include towing.