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

[foobar]

Hello folks,

I'm pleased to announce that the missus and I picked up our brand spanking new 2022 Globetrotter 27 FB Twin. Given that the factory shut down the week after ours was manufactured in order to convert to 2023 production, our trailer was one of the last few 2022 models that were made. Nothing like getting a years depreciation in less than a week

Using a 2016 Cayenne S, we towed the trailer from the dealer in Buda, Tx to our home in Dallas. Just a touch less than 250 miles.

We had purchased a customized Eaz Elite 1000 WD hitch and 2 husky friction anti-sway bars from Can Am RV in London, Ontario.

After spending 2 hours installing and setting up the WD hitch in the dealer parking lot starting at 1pm (the dealer refuses to install anything that they did not sell) when the temp was 104F in-the-shade, I was about done for.

But, still needed to install the Tekonsha Prodigy RF controller. Took about an hour to figure out "where" to mount it on the trailer A-Frame, and about 20 minutes to install it. Then I spent 45 minutes trying to figure out why it wouldn't pair. The hand held unit kept claiming that the A-frame mounted controller wasn't powered from the trailer (huh?). So on a whim, I pressed the battery disconnect button once in order to power up the trailer systems. And guess what ... the controller proceeded to pair up and work just fine. Thank you Airstream for wiring the 7 pin cable incorrectly and creating an unsafe installation . I'll have to fix that, but it was time to "hit the road".

I decided that the friction anti-sway bar installation could wait until I got home to install as long as I drive slow enough. And that assumption proved to be true, so don't give me any crap about it

Well, then came the first lesson learned ... don't head North on I35 from South of Austin in rush hour when you haven't tuned the brake controller. Hitting the brakes for the first time was "entertaining". I'll just leave it at that ...

Anyway, the rest of the trip went fine. The Cayenne towed like a beast. 415ft-lbs of torque, all of which is available at 1350rpm and almost 450hp meant that the Cayenne had plenty of oomph to accelerate (0 to 60 in about 7-8 seconds while towing is just fine, thank you very much). The Cayenne got 12mpg when towing between 65 and 70mph.

We arrived at home at about sundown (8:30pm give or take) on Friday, July 22, 2022.

Here is a photo of the glorious occasion! Also added a couple of photos of the interior taken the next morning. Please ignore the optical distortion from the fish eye lens on the interior shots.

We are so excited !!

[Dennis C]

Congrats! Glad you had a good experience!

Your neighborhood looks just like my parents’ old neighborhood over by Northpark.

[Verdecamp]

Congratulations! Safe travels!

Cheers

[foobar]

Hello again. On the way home from picking up the trailer, we stopped by a CAT scale and made some measurements.

The Cayenne S was empty except for the driver and passenger up front and a full tank of fuel.

The Airstream had full propane bottles and a couple of Interstate Flooded Lead Acid batteries up front, but was otherwise empty (except for whatever Airstream provided at the time of purchase). Note: We drained all of the Airstream tanks before we left the dealer lot.

Measurements:

Pass number 1 on the CAT Scale (trailer hooked up, with tension on WD bars):

3060 lbs TV Front Axle Load
3260 lbs TV Rear Axle Load
5880 lbs TT Axles Load

Pass number 2 on the CAT scale (trailer hooked up, no tension on WD bars)

2460 lbs TV Front Axle Load
4080 lbs TV Rear Axle Load
5660 lbs TT Axles Load

Pass number 3 (tow vehicle only, full tank, 1 driver, 1 passenger up front)

2860 lbs TV Front Axle Load
2620 lbs TV Rear Axle Load

Calculated values:

5480 lbs TV weight

12200 lbs Gross Combined Weight

6720 lbs TT Weight = Gross Combined Weight - TV Weight

1060 Tongue Weight (includes hitch weight @ 95lbs + friction anti-sway (2*14.6lbs) + Tekonsha Brake Controller @ 5.5lbs)

Now, let's calculate the Tongue Load Transferred to TT Axles when WD is active:
220 lbs transferred to TV axles when WD System is Activated
840 lbs Tongue Load transferred to TV axles

Trailer gross weight (empty, except for propane bottles):
6720 lbs Travel trailer gross weight (includes weight of hitch/anti-sway/brake-controler)

Remaining trailer cargo capacity:

7600 lbs GVWR for trailer

7600 GVWR - 6720 trailer gross weight --> 880 lbs remaining for cargo capacity. That's not very much...

Airstream spec for tongue weight is 875 lbs for a GT 27 FB Twin.

The measured tongue weight is 1060 lbs.

The tongue weight seems high, right? Not really...

875lbs from Airstream spec plus 94.5 lbs for WD hitch + 2 * 14.6 lbs for ant-sway bars + 5.5 lbs for Tekonsha = 1004.7 lbs

The measured tongue weight (1060 lbs) - 1004.7 lbs = 55.3 lbs.

When I calculate the weight of propane in two 30 lb cylinders, it comes out to be 55lbs ! That's almost exactly the discrepancy between what Airstream says the tongue weight is and the actual tongue weight that I measured.

So, my conclusion is ... while Airstream states that their trailer weight and tongue weight spec includes two full tanks of propane, the measured data says otherwise.

So when reading Airstream spec sheets, you have to add the weight of your WD hitch, anti-sway bars (if you are using those) and your brake controller. AND, you have to add the appropriate amount of propane weight to get to the actual real life tonque weight value you will experience on your tow ball.

The bigger and heavier your hitch configuration is, the higher your measured tongue weight will be. And ... no ... the hitch weight is "not" part of the weight of your tow vehicle :-)

I have been asking for someone to provide the raw weight data from an Airstream fresh after delivery. No one seems to have it, so I thought I would make an extra effort to get this done.

Now, it's time for some upgrades !!!

[foobar]

Originally Posted by Dennis C

Congrats! Glad you had a good experience!

Your neighborhood looks just like my parents’ old neighborhood over by Northpark.

Thanks Dennis!

It's funny how the local home architectures are roughly uniform for the most part ...

[foobar]

Originally Posted by Verdecamp

Congratulations! Safe travels!

Cheers

Thanks Verdecamp!

[foobar]

Originally Posted by foobar

Hello again. On the way home from picking up the trailer, we stopped by a CAT scale and made some measurements.

The Cayenne S was empty except for the driver and passenger up front and a full tank of fuel.

The Airstream had full propane bottles and a couple of Interstate Flooded Lead Acid batteries up front, but was otherwise empty (except for whatever Airstream provided at the time of purchase). Note: We drained all of the Airstream tanks before we left the dealer lot.

Measurements:

Pass number 1 on the CAT Scale (trailer hooked up, with tension on WD bars):

3060 lbs TV Front Axle Load
3260 lbs TV Rear Axle Load
5880 lbs TT Axles Load

Pass number 2 on the CAT scale (trailer hooked up, no tension on WD bars)

2460 lbs TV Front Axle Load
4080 lbs TV Rear Axle Load
5660 lbs TT Axles Load

Pass number 3 (tow vehicle only, full tank, 1 driver, 1 passenger up front)

2860 lbs TV Front Axle Load
2620 lbs TV Rear Axle Load

Calculated values:

5480 lbs TV weight

12200 lbs Gross Combined Weight

6720 lbs TT Weight = Gross Combined Weight - TV Weight

1060 Tongue Weight (includes hitch weight @ 95lbs + friction anti-sway (2*14.6lbs) + Tekonsha Brake Controller @ 5.5lbs)

Now, let's calculate the Tongue Load Transferred to TT Axles when WD is active:
220 lbs transferred to TV axles when WD System is Activated
840 lbs Tongue Load transferred to TV axles

Trailer gross weight (empty, except for propane bottles):
6720 lbs Travel trailer gross weight (includes weight of hitch/anti-sway/brake-controler)

Remaining trailer cargo capacity:

7600 lbs GVWR for trailer

7600 GVWR - 6720 trailer gross weight --> 880 lbs remaining for cargo capacity. That's not very much...

Airstream spec for tongue weight is 880 lbs for a GT 27 FB Twin.

The measured tongue weight is 1060 lbs.

The tongue weight seems high, right? Not really...

875lbs from Airstream spec plus 94.5 lbs for WD hitch + 2 * 14.6 lbs for ant-sway bars + 5.5 lbs for Tekonsha = 1004.7 lbs

The measured tongue weight (1060 lbs) - 1004.7 lbs = 55.3 lbs.

When I calculate the weight of propane in two 30 lb cylinders, it comes out to be 55lbs ! That's almost exactly the discrepancy between what Airstream says the tongue weight is and the actual tongue weight that I measured.

So, my conclusion is ... while Airstream states that their trailer weight and tongue weight spec includes two full tanks of propane, the measured data says otherwise.

So when reading Airstream spec sheets, you have to add the weight of your WD hitch, anti-sway bars (if you are using those) and your brake controller. AND, you have to add the appropriate amount of propane weight to get to the actual real life tonque weight value you will experience on your tow ball.

The bigger and heavier your hitch configuration is, the higher your measured tongue weight will be. And ... no ... the hitch weight is "not" part of the weight of your tow vehicle :-)

I have been asking for someone to provide the raw weight data from an Airstream fresh after delivery. No one seems to have it, so I thought I would make an extra effort to get this done.

Now, it's time for some upgrades !!!

Thought that I would also point out that the rule of thumb that 1/3rd of the tongue weight is transferred to the tow vehicle and 2/3rds is transferred to the travel trailer is ... drum roll please ... totally incorrect and is a completely useless rule of thumb.

Real world example:

In my setup, out of the 1060 total tongue weight, the weight that is transferred to the tow vehicle is 220lbs, which is 20.8% of the tongue weight.

The tongue weight that is transferred to the trailer axles is 840 lbs, which is 79% of the total tongue weight.

[waninae39]

https://www.canamrv.ca/blog/category/hitch-hints/good measurements

you may want to add a 1/2 link and the WB chain so that the front and rear of the TV have closer numbers with the WD on

check the CANAM web site for how to do this 1/2 link

[foobar]

Originally Posted by waninae39

https://www.canamrv.ca/blog/category/hitch-hints/good measurements

you may want to add a 1/2 link and the WB chain so that the front and rear of the TV have closer numbers with the WD on

check the CANAM web site for how to do this 1/2 link

Thanks for the suggestion. I am already using a 3 links of WD chain + a couple of bolts (each half inch bolt yields ~ 1/3rd link of chain adjustment). The front and rear vertical suspension displacement is nearly equal with the setup I have now and feels rock solid when towing. When I went with 4 links of WD tension, the front displacement is 3/4" lower and the rear vertical lift increases by nearly an inch.

So this is a reasonable setup for now.

However, once I load up the trailer and tow vehicle for the first trip, I'll go over the hitch setup a bit more carefully and tune it a bit better.

Note that the Cayenne GAWR spec for the rear axle is 420 lbs higher than the front axle. Given that I'll be close to the max GVWR for the tow vehicle once I load up the TV and TT, I'll ultimately allow more weight on the rear axle than the front axle as long as the stability and steering feel good when towing.

And, yes, for everyone other than waninae39 that is thinking I need a bigger tow vehicle, I'm sure that an 18 wheeler and an F350 dual axle would do better, so no need to state the obvious. It's worth observing that the earth didn't stop spinning and the Cayenne + 27 FBT didn't immediately summersault and kill my wife and I, along with baby seals and everyone else sharing the freeway on that day because I wasn't towing with a 1 ton pickup The Cayenne will work fine for me.

[foobar]

Another data point worth mentioning is that I also experienced 15mph crosswinds, gusting to 25 - 30mph for about half of the 250 mile trip.

No stability problems at 65-70mph towing speed with this stiff, gusty cross wind that arrived a various angles as the road changed direction periodically.

Nor did I have any trouble with 18 wheelers or busses passing at different speeds in adjacent lanes.

Overall, this wasn't a white knuckle experience.

[AlbertF]

Originally Posted by foobar

Thought that I would also point out that the rule of thumb that 1/3rd of the tongue weight is transferred to the tow vehicle and 2/3rds is transferred to the travel trailer is ... drum roll please ... totally incorrect and is a completely useless rule of thumb.

Real world example:

In my setup, out of the 1060 total tongue weight, the weight that is transferred to the tow vehicle is 220lbs, which is 20.8% of the tongue weight.

The tongue weight that is transferred to the trailer axles is 840 lbs, which is 79% of the total tongue weight.

You’re quite right about that. With longer trailers, the transfer to the trailer axles is diminished. The rule of thirds may have been accurate when ordinary travel trailers were only 16 to 18’ long.

[pakman31]

Originally Posted by foobar

Another data point worth mentioning is that I also experienced 15mph crosswinds, gusting to 25 - 30mph for about half of the 250 mile trip.

No stability problems at 65-70mph towing speed with this stiff, gusty cross wind that arrived a various angles as the road changed direction periodically.

Nor did I have any trouble with 18 wheelers or busses passing at different speeds in adjacent lanes.

Overall, this wasn't a white knuckle experience.

Awesome! As one who tows a similar Airstream with F350 diesel, I am very jealous of your set up.



I would have much preferred to tow with an SUV, but was convinced otherwise.


I get about 14 mpg while towing, and I think you are in that same ball park with a much sweeter TV.


Best of luck!

[ModernVista]

A note about the pairing- as I’ve done a few of these RF wireless Prodigy installs with 3 different t Cayennes in my 28. the car needs enough current pull to see the device the first time. The LED lights don’t pull enough, so I have used a 7 pin gadget that pulls a larger charge to do the first time pair.

It’s possible that the trailer pulled a charge from the 7-pin harness when you turned it on. Now that you are paired, check the turn lights and brake lights with the airstream switch off.

Cheers! And enjoy!!

[foobar]

Originally Posted by pakman31

Awesome! As one who tows a similar Airstream with F350 diesel, I am very jealous of your set up.



I would have much preferred to tow with an SUV, but was convinced otherwise.


I get about 14 mpg while towing, and I think you are in that same ball park with a much sweeter TV.


Best of luck!

Well pakman31, you also have a great tow vehicle that will serve you well. You won't have to weigh everything that goes into your tow vehicle and trailer like I have to :-) There are some downsides to what I'm trying to do for sure.

I will likely eventually end up with an F250 or F350, but I'd like to avoid buying when dealers are asking for ridiculous markups over MSRP. And in the interim, I get to disconnect the trailer and have some fun with the Cayenne when I reach my destination!

[Mikebrady62]

Very nice looking from the front bumper to the rear of the trailer. Inside and out!
Happy Camping to you!

[foobar]

Originally Posted by Mikebrady62

Very nice looking from the front bumper to the rear of the trailer. Inside and out!
Happy Camping to you!

Gracias Amigo !! Looking forward to our first real trip ... but first ... some solar panels and lithium batteries need to go in ...

[latarheel]

What’s the hitch weight capacity on the cayenne S and tongue weight On the 27 FBT? Did you do the cat scale weight and compare ? I remember my first tow! White knuckles

[foobar]

Originally Posted by latarheel

What’s the hitch weight capacity on the cayenne S and tongue weight On the 27 FBT? Did you do the cat scale weight and compare ? I remember my first tow! White knuckles

Hi latarheel, CAT scale data is in posting #2 in this thread.

Measured tongue weight was 1060lbs.

Hitch capability is around 1170lbs in terms of tongue weight, but I need to look up the number and refresh my memory.

I have plans to reduce tongue weight anyway (aluminum propane tanks, removing batteries from the A-frame box, etc) to minimize the load on the Cayenne. No reason to stress the tow vehicle any more than I have to.

The Cayenne tow limit is 7716 lbs and the 27 FBT Airstream gvwr is 7600. My biggest challenge is the tongue weight and Cayenne load capacity however.

[uwe]

Originally Posted by foobar

Hi latarheel, CAT scale data is in posting #2 in this thread.

Measured tongue weight was 1060lbs.

Hitch capability is around 1170lbs in terms of tongue weight, but I need to look up the number and refresh my memory.

I have plans to reduce tongue weight anyway (aluminum propane tanks, removing batteries from the A-frame box, etc) to minimize the load on the Cayenne. No reason to stress the tow vehicle any more than I have to.

The Cayenne tow limit is 7716 lbs and the 27 FBT Airstream gvwr is 7600. My biggest challenge is the tongue weight and Cayenne load capacity however.

My 2012 Cayenne S has a 7716lbs tow capacity, 1708lbs payload, and a max tongue weight of 617lbs. Pretty much same as yours. I tow my 25ft fb with it, tongue weight 1100lbs, and it does great. I use a blue ox WD system with 1500lb bars. The tongue weight is, like you stated, the Achilles heel. I have 2 friends that also tow with a cayenne, a 2014 Diesel, and another 2013 S. The Diesel has seen a lot of miles towing a 25ft International all over the West Coast. We recently removed the bumper ( for painting) and did a very thorough check not he tow hitch attachment. There were absolutely no signs of stress whatsoever. It is a massive beast. In comparison...a Nissan 08 Titan has a payload of roughly 1350lbs.
My Cayenne tows superbly well, but technically, the vehicle is grossly overloaded due to published tongue weight values. I am not worried about it, though, especially not after inspecting my friends Diesel Cayenne tow hitch.

[foobar]

Originally Posted by uwe

My 2012 Cayenne S has a 7716lbs tow capacity, 1708lbs payload, and a max tongue weight of 617lbs. Pretty much same as yours. I tow my 25ft fb with it, tongue weight 1100lbs, and it does great. I use a blue ox WD system with 1500lb bars. The tongue weight is, like you stated, the Achilles heel. I have 2 friends that also tow with a cayenne, a 2014 Diesel, and another 2013 S. The Diesel has seen a lot of miles towing a 25ft International all over the West Coast. We recently removed the bumper ( for painting) and did a very thorough check not he tow hitch attachment. There were absolutely no signs of stress whatsoever. It is a massive beast. In comparison...a Nissan 08 Titan has a payload of roughly 1350lbs.
My Cayenne tows superbly well, but technically, the vehicle is grossly overloaded due to published tongue weight values. I am not worried about it, though, especially not after inspecting my friends Diesel Cayenne tow hitch.

The problem with European tow vehicles is that it's really tough to get the actual tow limits for WD hitches.

Couple of data points to consider:

1. In Germany, if you have a vehicle that can tow a trailer that weighs over 3500 kg, there are significant taxation and licensing issues involved.

2. In the EU, WD hitches are illegal (this was done many decades ago to prevent US trailer manufacturers from putting EU trailer companies out of business), so accurate WD hitch limits are often not available.

Because of #1 above, most capable EU tow vehicles like the Cayenne "magically" have a tow limit of 3500kg (7716lbs).

A friend of mine is a tech at Porsche and told me the actual WD hitch limit is 1157lbs on my 2016 Cayenne S but that is not documented in many locations (here is one: https://ds.aytservicecenter.com/spec...yle_id=9287252).

Many Cayenne hitches have a label that say 660lbs. Others have a label that say 772 lbs. 772 lbs "magically" happens to be 10% of the tow limit of 7716 lbs (rounded up to 772) in order to match the USA standard of requiring a tongue load = 10% of the trailer weight for stability. Side note: Some Porsche dealers know that the 660lb sticker is incorrect and will order and install a sticker for free that says 772lbs if you ask them. Other dealers are clueless...

See the problem here? The documented Cayenne hitch towing limits are arbitrarily set by regulation/taxation concerns and not by actual physical tow limits.

My plan? I will absolutely ensure that the tongue weight is less than 1157 lbs and get it as close to 772lbs as possible via removing the lead acid batteries (and installing lithium over the trailer axles), changing the propane tanks to aluminum, and minimizing the trailer load placed forward of the axles. I think I can get the tongue weight down to the 850-900lb range without too much pain and that should be adequate. I also paid a visit to Can Am RV (towing experts in Canada) and had them reinforce my factory hitch to better withstand the upward forces placed on it by a WD hitch.

The Cayenne is very stiff and sound from a structural perspective as you can also tell from the weight (with a driver and one passenger) = 5500lbs. 420hp and 406ft-lbs of torque (fully available at 1350rpm) is actually better than many diesel engine based pickup trucks.

I have no concerns with towing my Globetrotter 27 FB Twin, but there are many folks on this forum that believe that doing this will result in instant death and destruction the first time I have to make an emergency stop or lane change and the only cure is an F250 or F350 with a suspension that is so stiff that you don't need a WD hitch while the overly stiff TV suspension beats the trailer to death and contributes to front end separation issues and busted rivets (I say this with tongue firmly inserted in my cheek, so I'm poking a little fun here). Having said this, after a couple of years when trucks are more available and not being sold for $30K over MSRP, I might eventually get a more capable tow vehicle with higher cargo capacity so I can carry more gear without having to be so anal about tracking weight.