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-   -   Tongue Weight and Stability (https://www.airforums.com/forums/f464/tongue-weight-and-stability-23508.html)

Steve Heywood 06-12-2006 12:49 PM

Tongue Weight and Stability
 
I recently made an interesting discovery. My fridge died while dry camping so I bought a 100 qt. ice chest, some ice, and continued my trip. While underway I strapped the ice chest to my couch as far forward as I could. I noted to myself that my trailer was especially well behaved on the interstate, barely reacting to passing trucks and cross-winds.

When I reached Phoenix we unloaded the trailer and towed it to Oasis RV in Tucson to get the fridge fixed (more on that in another post). During the trip on I-10 from Phoenix to Tucson I noticed that my trailer was up to it's old tricks of reacting to passing trucks.

My conclusion is that the 100 lb. reduction in tongue weight (the full ice chest weighed at least that much) was to blame. I plan an experiment when I retrieve my trailer on Friday to confirm my theory. I'll report back with the results.

silverback 06-12-2006 02:13 PM

this is what's known as weight distribution...
 
Steve,
I don't know what type hitch you're using but if it has weight distribution adjustments you should try to recreate the 100lb. cooler effect. Sounds like you need more weight toward the tongue (but I'm no genius at this).
-Ken

Alumaholic 06-12-2006 03:17 PM

I think Silverback nailed it.
When I traded my 2003 Z71 Suburban for the Chevy 2500 HD, I kept the same 1000# hitch setup. Then I read a post by Inland Andy on these forums that stated you need lighter equalizer bars as you move to a Heavy Duty suspension.

Later, Nick Crowhurst, also on these forums, provided an excellent analysis along with precise formula for computing hitch requirements. As as consequence, I now use 750# bars.

Perhaps your "Igloo Experience" is telling you your bars are too heavy or too torqued to allow you to keep enough weight on the hitch.

P.S. What happened at the Oasis? Inquiring minds want to know.

bhayden 06-12-2006 04:47 PM

New to towing. In fact this weekend was the first real trip with the trailer. Besides new trailer brakes I also changed from an EA-Z-Lift hitch to a Reese trunion type. The trailer towed noticably better and I attribute this mostly to now having an adjustable height ball set to the correct height. The EA-Z-Lift was fixed and ~4" lower than the 19-1/2" specified.

I've never used the Reese set-up before and it always seemed undoly complex. I mean, what's with this adjusting the hitch angle stuff? OK, so as I understand it what this does is allow some "fine tuning" of the tension on the equalizer bars. I set the angle by installing the recommended seven washers (spacers) and the trunion bars snapped into place with one more than the required minimum number of links. I measured wheel well openings on the TV and it appears they are 1" less than without the trailer all the way around. What's more the trailer now appears perfectly level when hooked up. According to Reese there should be about 1" more sag in the rear than the front which would lead me believe I have too much tension on the bars. However, leveling the TV seems to work and again, according to Reese as long as there's not more compression on the front I should be OK. FYI the TV is AWD so losing traction in the rear isn't an issue. I'm wondering though if I should remove a few washers (i.e. make the hitch a little closer to level) to reduce the tension on the trunion bars and bias the weight a little more over the rear wheels.

Anyone have a good tip on where to find a scale that will weigh each axle of the rig to see exactly what the distribution is?

jcanavera 06-12-2006 05:26 PM

Quote:

Originally Posted by klevan
I think Silverback nailed it.
When I traded my 2003 Z71 Suburban for the Chevy 2500 HD, I kept the same 1000# hitch setup. Then I read a post by Inland Andy on these forums that stated you need lighter equalizer bars as you move to a Heavy Duty suspension.

Silvertwinkie was up at Moraine View and told me the exact same story. He also has a 2500 Suburban and recently changed out his bars to lighter bars. He said it made a big difference in towing stability.

Jack

Steve Heywood 06-12-2006 11:43 PM

Quote:

Originally Posted by jcanavera
Silvertwinkie was up at Moraine View and told me the exact same story. He also has a 2500 Suburban and recently changed out his bars to lighter bars. He said it made a big difference in towing stability.

Jack

The service manager at Oasis knew what year my trailer was without asking. He told me that in 99 or 2000 Airstream moved the axles back 2 inches (on the 30' dinette models) in order to increase tongue weight and improve stability. He also stated that my trailer was very particular with regards to hitch settup and being absolutely level when hitched.

I suspect that I'm running too heavy a springbar with my hitch. I have an EazLift with 1,000 lbs bars. Viewed from the side it appears to be every so slightly nose up. My plan is to replace my EazLift with a Reese Straight-Line (Dual-Cam) with 800 lbs bars and a shank which will allow for a slightly lower ball height.

In order to comfirm my earlier experience I plan to fill my cooler with 100 lbs of weight and take it with me when I pick up my trailer on Friday.

Steve Heywood 06-12-2006 11:47 PM

Quote:

Originally Posted by klevan
P.S. What happened at the Oasis? Inquiring minds want to know.

Oasis is a great dealership. A bit "old-fashioned" and kind of dumpy looking, but that's OK. The service department so far has proven to be first rate and the service manager is very knowledgable.

I'll take that over "flash" and a bunch of airheads any day.

scottanlily 06-13-2006 01:20 AM

Hello bhayden,

The deal with the hitch head angle is that when setting up the bars ,they should have some amount of curvature to them in the fully loaded position.
IF they pull up too far ,you can angle the hitch head down so the bars take a curvature in the loaded position .The bars should angle down when not sinched up in place ,in other words they should not be level or parallell to the tongue .The angle depends on the rating of the bars and the tow vehical you have ,heavy duty 3/4 ton truck ,lighter bars ,1/2 ton or car heavier bars.The angle should not be excessive.thats how the WD hitches load the frames of the tv and trailer thru those bars.

Scott

bhayden 06-13-2006 09:26 AM

After reading the instructions (gasp) and actually using the Reese hitch it's not as complex as I first thought. I understand the angle adjustment for "dialing in" the tension. It's a nice concept because right now I think I'm putting just a shade too much weight on the front but not enough to drop an entire link. The angle adjustment lets you get a "half link" adjustment. The other advantage of the Reese trunion style is you don't need as much room under the hitch to slide the bars in. They can be an issue when you're hooking/unhooking "off road".

I think the big difference with the Reese vs the EA-Z-Lift is the height adjustment. I saw an EA-Z-Lift (or Robins copy) yesterday that used an adjustable head. I guess with the adustable head you sort of need the extra bolt to snug up the installation so might as well make it adjust for angle.

I'm using 800# bars with the Argosy 24' which I think is just about right. Could probably get by with the lighter bars but the 1000# bars would definitely be too much. Don't remember what the EA-Z-Lift bars are rated at but I think they're pretty comparable.

-Bernie

Alumaholic 06-13-2006 11:03 AM

Quote:

Originally Posted by Steve Heywood
Oasis is a great dealership. A bit "old-fashioned" and kind of dumpy looking, but that's OK. The service department so far has proven to be first rate and the service manager is very knowledgable.

I'll take that over "flash" and a bunch of airheads any day.

My sentiments exactly. I've enjoyed great service at Oasis since we found them in 1998. Jay Breshears, the Service Manager, is a veritable font of information and the keeper of the "straight scoop," as opposed to the "bum scoop" we so often receive. Rick, in the Parts Department, has always shipped any parts I need the same day I call or the very next day.
I'm glad you had a similar experience.

joecolao 06-13-2006 11:22 AM

Tongue weight and stabilty
 
Hello Steve, I tow with an Astro van. I have a 34' excella 1000. It weighs 8700 lbs. My tongue weight is 780 lbs. I have no sway when trucks pass me at all.
We get our rig weighed at least once a year. We have each wheel of our rig weighed individually.
We use an EZ lift welded hitch head with 750 lb. weight distribution bars. If we are towing locally we do not use any anti sway bars. When we go on interstates we do, although if the pavement is wet I take off most of the friction.
If you want to learn from serious professionals about towing safely I would suggest that you contact the Recreational Vehicle Saftey Education Foundation or RVSEF and contact Andy Thompson from Can-Am-Rv in London Ontario.
We tow about 10,000 to 20,000 miles per year.
We are currently in Rapid Ciy, South Dakota and on our way to Salem Or. for the International Rally and then onto Alaska. We hope to be home in Long Island NY by early September.
You should be congratulated for being so aware of the changes in your rigs handling and wondering why the change. Most people leave it un-noticed or just buy a bigger anit-American gas guzzling truck and sacrifice handling for power. Good luck.

bhayden 06-13-2006 11:38 AM

Quote:

Originally Posted by joecolao
I tow with an Astro van. I have a 34' excella 1000. It weighs 8700 lbs. My tongue weight is 780 lbs. I have no sway when trucks pass me at all.

Whoa, we're using a 2000 GMC Safari AWD with factory tow package and the rated max towing capacity is 5800. That happens to be exactly the GVWR of our 1978 Argosy 24. Haven't check the ball to rear axle length ratio but we exceed the TV wheelbase to trailer length guidelines by about three feet.

I'm still getting the hitch, brakes, tire pressures, etc. dialed in. On our first big trip over Washington Pass (North Cascades Hwy, 5,500' elev) I was surprised at how well the rig did. We kept the load down to a minimum so I'm guessing 600-800 pounds in the van and less than 4500# trailer weight. Haven't used the friction sway control yet and didn't need it. However, I'm guessing it would be a help in cross winds we often encounter in mtn passes and eastern Washington.

I put a synthetic blend oil in the engine which made a noticable difference and I've got a set of heavy duty KYB shocks I need to get put on. What else have you done to beef up the towing capacity of your Astro? Unloaded our ground to fender well distance is 29-1/2". It's just a shade over 28-1/2" with the trailer hitched up. Our tongue weights aren't all that different but I'm wondering how much suspension compression you experience. We're seeing about 11mph back and forth over the mountains. I'm guessing we're around 12mpg if we could ever find flat roads without winds.

-Bernie

Alumaholic 06-13-2006 05:46 PM

Quote:

Originally Posted by joecolao
Hello Steve, I tow with an Astro van. I have a 34' excella 1000. It weighs 8700 lbs. My tongue weight is 780 lbs. I have no sway when trucks pass me at all.
We get our rig weighed at least once a year. We have each wheel of our rig weighed individually.
We use an EZ lift welded hitch head with 750 lb. weight distribution bars. If we are towing locally we do not use any anti sway bars. When we go on interstates we do, although if the pavement is wet I take off most of the friction.
We tow about 10,000 to 20,000 miles per year.
We are currently in Rapid Ciy, South Dakota and on our way to Salem Or. for the International Rally and then onto Alaska. We hope to be home in Long Island NY by early September.
You should be congratulated for being so aware of the changes in your rigs handling and wondering why the change. Most people leave it un-noticed or just buy a bigger anit-American gas guzzling truck and sacrifice handling for power. Good luck.

Joe, Run this by me again, please. Even assuming you have a 3.73 axle ratio, your 2000 Astro has a tow limit of 6,100 lbs. You say your Excella weighs 8700. :blink: Call me anti-American if you wish, but I'm not sure exactly what you are advocating. Does the RVSEF really say an Astro has the power, and the wheel base to safely tow a 34' Excella.

Steve Heywood 06-13-2006 06:49 PM

Quote:

Originally Posted by klevan
My sentiments exactly. I've enjoyed great service at Oasis since we found them in 1998. Jay Breshears, the Service Manager, is a veritable font of information and the keeper of the "straight scoop," as opposed to the "bum scoop" we so often receive. Rick, in the Parts Department, has always shipped any parts I need the same day I call or the very next day.
I'm glad you had a similar experience.

Jay called me today to tell me the bad news about my 9 year old Dometic. Despite an earlier report that it seemed fine he said as soon as the outside temp topped 100 degrees my fridge went over 50 degrees inside. So when I pick up my trailer on Friday I'll have a brand new Dometic and a much lighter wallet!

Alumaholic 06-13-2006 07:10 PM

Bummer..
 
Tucson is very challenging for our refrigerators. Especially if you are parked in front of Oasis pointing north and south, and your refer is on the west side.
I had a similar problem when I took our '76 Safari 23' with 33 year old refer to Oasis in 1999. We backed in, tongue south and refer west, in June. The poor ammonia evaporation refer just could not cope. We kept it anyway, figuring that we don't camp in Tucson in the summer, we go to Colorado. When we sold the '76 in 2001, it still had the old refer, and I think it still does. Having said all this, the refer really was marginal, and Tucson has a way of identifying those that are starting to underperform. If you plan any trips that could tax the system, you are doing the right thing. :)

silverback 06-13-2006 07:39 PM

loyal Oasis RV customer here too
 
I consider Joe, Jay, Ricky and Richard friends who also happen to be our AS dealer. Then again I try not to see them too often... ;)
K & L

scottanlily 06-13-2006 11:59 PM

Hello to all ,

Im 100% certain the astro van neither has the capacity nor the tow rating for anywhere near that 8700# mark ,if it still has the 4.3 v6 i don't know how it can pull it up any mountain grade . The rear overhang of those little vans is very short so they woud not have the induced sway problems ,but man hold on in a panic situation ,the tail is waggin the dog!

Scott

herrgirdner 06-14-2006 08:36 AM

I don't like to be a conformist, and take the contrary view whenever possible. That being said, I have to chime in with the positive comments about Oasis. Not much flash, but there's a solid block of knowledge and expertise behind that "rusty old chain link fence".
regards

nickcrowhurst 06-14-2006 11:10 AM

[quote=klevan]Joe, Run this by me again, please. quote]

Ken, more details in post #8 at https://www.airforums.com/forum...119#post229119

Nick.

jcanavera 06-14-2006 12:34 PM

Quote:

Originally Posted by klevan
Joe, Run this by me again, please. Even assuming you have a 3.73 axle ratio, your 2000 Astro has a tow limit of 6,100 lbs. You say your Excella weighs 8700. :blink: Call me anti-American if you wish, but I'm not sure exactly what you are advocating. Does the RVSEF really say an Astro has the power, and the wheel base to safely tow a 34' Excella.

I owned a '91 Astro Ext which has the largest capacity tow rating of any Astro built. It had a premium gas V6 along with a 4.10 rear axle. Towing capacity was 6,500 lbs. I pulled a 28' Thor built aluminum framed SOB and used a Reese dual-cam sway control hitch. I towed for two years and while the Astro was up to the task, that 28' SOB was a handful. The problem was the Astro just didn't have enough mass to deal with the forces placed on the trailer. Not that it swayed, it was just the issue that the trailer and Astro were literly pushed as a unit, when dealing with strong winds. I could do about 300 miles a day, and was worn out by that point.

I personally can't figure how a 2000 Astro, with less capacity can safely handle an 8,700 lb Excella much less mechanically hold up to towing such a trailer.

Jack


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