weight distribution and tire loading

[out of sight]

I thought I'd look at weight distribution in a different way by looking at tire loading rather than vehicle loading. It turns out that the most heavily loaded tires, measured as a load percent of the tire load rating, are the front tires of my tow vehicle. What this means is that if I use a weight distribution hitch I will make the problem worse. With the trailer attached on the hitch ball, without a weight distribution hitch, the front tire loading is reduced to approximately equal to the rear TV tire loads. The % of each tire load to the max loading rating of the tires then comes out to:

trailer tires 56%
front TV tires 65%
rear TV tires 65%

The only way to further equalize the tire loading percentages would be to take cargo weight from the TV and put it over the axles of the trailer.

[ROBERT CROSS]

You might consider a higher load rated tires if your current situation is worrisome for you.

IMO... 35% wiggle room acceptable.

Bob
🇺🇸

[out of sight]

I'm not worried about it. Actually I'd be more worried about the Airstream tires having experienced two blowouts with thousands of dollars of wheel well damage. I am happy with the lowest possible trailer tire loads.

[ROBERT CROSS]

^
Not with the '19 I hope? Is it equipped with the newer GYE's?

Bob
🇺🇸

[azflycaster]

What are your weight percentages without the trailer attached? By changing the dynamics (lowering the front tire weight) you could be creating an unstable situation. The purpose of the weight distribution hitch is to restore the front end weight. If you are concerned about tire wear because the load is not equal, rotate the tires.

[out of sight]

I had the blowouts on a 22 sport single axle trailer. The tires were factory Goodyear Endurance load class D. I heard that Airstream recently upgraded the factory tires to load class E because of this problem.

When you have a flat/blowout on a single axle trailer you don't know it until the tire starts disintegrating. I now have a two axle trailer and I hope that I can catch a flat before the tire wipes out my wheel wells. I'm also looking into a TPMS. Airstream should be providing a TPMS on all new trailers but they don't. Maybe they are making too much money on wheel well repairs.

[out of sight]

Originally Posted by azflycaster

The purpose of the weight distribution hitch is to restore the front end weight.

I have a diesel pickup truck which is designed to operate with a lot of payload. Unloaded it has a poor weight distribution, and poor rear wheel traction, with 62% of the load on the front axle. I don't want to restore the front end weight but rather I want to aim for a 50/50 weight distribution. If I drop 1000 lbs on the hitch ball that will do the trick. I will have more rear wheel traction and the rig will be more stable and more resistant to loss of control due to trailer sway.

[SteveSueMac]

Originally Posted by out of sight

I have a diesel pickup truck which is designed to operate with a lot of payload. Unloaded it has a poor weight distribution, and poor rear wheel traction, with 62% of the load on the front axle. I don't want to restore the front end weight but rather I want to aim for a 50/50 weight distribution. If I drop 1000 lbs on the hitch ball that will do the trick. I will have more rear wheel traction and the rig will be more stable and more resistant to loss of control due to trailer sway.

I also have a diesel 3/4T truck. When I drop the 980# (call it 1000) on it, about 500# gets lifted off the front axle. That creates (on my truck anyway) a severe understeer scenario. Using a WD hitch to restore half or more of that to the front axle of the truck is helpful in keeping the steer tires in full contact with the ground. I also found in my setup that the closer I got to full restoration on the steer axle the less porpoising I experienced.

YMMV.... happy camping!

[ROBERT CROSS]

Originally Posted by out of sight

I have a diesel pickup truck which is designed to operate with a lot of payload. Unloaded it has a poor weight distribution, and poor rear wheel traction, with 62% of the load on the front axle. I don't want to restore the front end weight but rather I want to aim for a 50/50 weight distribution. If I drop 1000 lbs on the hitch ball that will do the trick. I will have more rear wheel traction and the rig will be more stable and more resistant to loss of control due to trailer sway.

What are you using for sway control? 🤔

Shall I guess...3/4 diesel doesn't need it.😂

Bob
🇺🇸

[gypsydad]

Originally Posted by SteveSueMac

I also have a diesel 3/4T truck. When I drop the 980# (call it 1000) on it, about 500# gets lifted off the front axle. That creates (on my truck anyway) a severe understeer scenario. Using a WD hitch to restore half or more of that to the front axle of the truck is helpful in keeping the steer tires in full contact with the ground. I also found in my setup that the closer I got to full restoration on the steer axle the less porpoising I experienced.

YMMV.... happy camping!

That is accurate...I have same experience as you. WDH is important.
I am baffled about the blowouts on the GYE's on the 22' Out of Sight mentioned...wonder what year at year his 22' was and if they were really GYE's; and not GY Marathons?? It is the Marathons that have been giving most of us fits over the years...The GYE's are only a couple years old now...

[out of sight]

Originally Posted by gypsydad

That is accurate...I have same experience. WDH is important. I am baffled about the blowouts on the GYE's on the 22' mentioned...what year was your 22' and are you sure they were GYE's not GY Marathons?? It is the Marathons that have been giving most of us fits over the years...The GYE's are only a couple years old now...

I stand corrected. They were Marathons. 2014 22 Sport.

[out of sight]

Originally Posted by ROBERT CROSS

What are you using for sway control?

The truck has electronic sway control. You still feel a slight bump when getting passed by a Greyhound doing 85 MPH but it doesn't really sway. If it did start swaying the ESC would automatically apply the appropriate brakes until it stops. But a trailer won't sway if you have 10% of the trailer weight on the tongue.

[SteveSueMac]

Originally Posted by out of sight

...snip....

But a trailer won't sway if you have 10% of the trailer weight on the tongue.

I’m not 100% sure on that....I think you may be less likely to experience sway with proper tongue weight (10-15% is the recommended range), and some here will argue that the aerodynamic shape of the AS trailer itself reduces chances of sway. All valid views. And - there are other x-factors that “overrule” some of these sway reduction approaches. Emergency maneuvers, an unforeseen pothole, edging off the tarmac in to dirt, excessive speed, blowouts, oncoming semis, etc. - all can overrule tongue weight as the sole determining factor of a sway event...

[gypsydad]

May have missed this, but are you using a WDH? If so, have you towed your 28' to the scales and weighed the trailer with truck attached on separate scales, then weighed the trailer without the truck attached, but tongue on separate scale to verify the tongue weight separate from the AS coach weight? Those numbers will give you a pretty good indication on which pressures you want to run in your AS tires, assuming your reading the tire manufacturer recommended PSI? (this applies for the TV tire pressures also...my Michelins on my F250 I run 80 PSI when towing.) For the GY Endurance tires, we run 45-50PSI as recommended for our AS weight...anything over that can cause stiff ride and issues with your cabinet hinges, cabinet latches, and rivets...just saying...

[out of sight]

Originally Posted by ROBERT CROSS

What are you using for sway control? 🤔

Shall I guess...3/4 diesel doesn't need it.😂

Bob
🇺🇸

Originally Posted by gypsydad

May have missed this, but are you using a WDH? If so, have you towed your 28' to the scales and weighed the trailer with truck attached on separate scales, then weighed the trailer without the truck attached, but tongue on separate scale to verify the tongue weight separate from the AS coach weight? Those numbers will give you a pretty good indication on which pressures you want to run in your AS tires, assuming your reading the tire manufacturer recommended PSI? For the GY Endurance tires, we run 45-50PSI as recommended for our AS weight...anything over that can cause stiff ride and issues with your cabinet hinges, cabinet latches, and rivets...just saying...

No WDH. No, I have not been to a CAT scale yet, but I did calculate the loads based on MFR load data and dimensions. I have also weighed the tongue using the old bathroom scale technique, mainly when I was towing the 28 with my SUV. In that case I had to use a WD hitch because my headlights were pointing at the sky. My RAM 2500 drops only 1 1/4 inch with the full tongue weight on the ball, so no need there.

I see your point about the lower tire pressure making for a softer ride, but that's not too good for your tires. I'm probably too tire sensitive after having two wheel wells destroyed. I run mine at the recommended 80 PSI for max load.

[gypsydad]

Originally Posted by out of sight

No WDH. No, I have not been to a CAT scale yet, but I did calculate the loads based on MFR load data and dimensions. I have also weighed the tongue using the old bathroom scale technique, mainly when I was towing the 28 with my SUV. In that case I had to use a WD hitch because my headlights were pointing at the sky. My RAM 2500 drops only 1 1/4 inch with the full tongue weight on the ball, so no need there.

I see your point about the lower tire pressure making for a softer ride, but that's not too good for your tires. I'm probably too tire sensitive after having two wheel wells destroyed. I run mine at the recommended 80 PSI for max load.

Well, with all respect to you, please get yourself a WDH; you should be using a WDH, especially with the larger AS's. It's more for control of both your TV and your AS... you want the weight distribution of the hitch to balance out your load with the Airstream. The vehicle antisway will work in conjunction if needed. Lots of YouTube on this...(and those who disagree for what ever reason, of course..)

Second, don't rely on the "spec sheet" for weights...get your truck/trailer weighed..everyone's truck and AS is different...a few hundred pounds in some cases... That will help with getting pretty accurate tire pressures.

3rd- recommend a TPMS system; it will give you peace of mind knowing the pressures of your AS tire pressures and temps...and warn you of pending issues....as you mentioned, blowouts are a pain to deal with and can be devastating to the undercarriage. Many posts here on the Forum like yours, who now swear by the TPMS.

[AirMiles]

Originally Posted by out of sight

No WDH. No, I have not been to a CAT scale yet, but I did calculate the loads based on MFR load data and dimensions. I have also weighed the tongue using the old bathroom scale technique, mainly when I was towing the 28 with my SUV. In that case I had to use a WD hitch because my headlights were pointing at the sky. My RAM 2500 drops only 1 1/4 inch with the full tongue weight on the ball, so no need there.

I see your point about the lower tire pressure making for a softer ride, but that's not too good for your tires. I'm probably too tire sensitive after having two wheel wells destroyed. I run mine at the recommended 80 PSI for max load.

Same as others stated above, when 1020# is added my F250 Diesel's ball, 420# comes off my front axle and 1440# is added to my rear axle. The axle weights flip-flop from 4820# front and 3840# rear to 4400# front and 5280# rear.

Then I use a weight distribution hitch to return my axles to an equal front/rear weight of 4760#. Equal weighting my axles works best for my truck, the same as it does for Gypsydad. Here is a link to my scale tickets documenting the above results: http://www.airforums.com/forums/f464...ml#post2217820 . I'd suggest going to a scale to see what adding your Airstream does to your truck's axle loads.

[out of sight]

Originally Posted by gypsydad

Well, with all respect to you, please get yourself a WDH; you should be using a WDH, especially with the larger AS's. It's more for control of both your TV and your AS... you want the weight distribution of the hitch to balance out your load with the Airstream. The vehicle antisway will work in conjunction if needed. Lots of YouTube on this...(and those who disagree for what ever reason, of course..)

Second, don't rely on the "spec sheet" for weights...get your truck/trailer weighed..everyone's truck and AS is different...a few hundred pounds in some cases... That will help with getting pretty accurate tire pressures.

3rd- recommend a TPMS system; it will give you peace of mind knowing the pressures of your AS tire pressures and temps...and warn you of pending issues....as you mentioned, blowouts are a pain to deal with and can be devastating to the undercarriage. Many posts here on the Forum like yours, who now swear by the TPMS.

No WDH for me. That would unbalance my tow vehicle and I would be riding down the street with overloaded front tires and underloaded rear tires. Not a good idea. Not to mention putting unnecessary load on the trailer tires.

I agree 100% with the TPMS however. I just wish Airstream would have supplied the internal sensors. Now I am stuck with external sensors or having to go thru the hassle of pulling all my tires off. Honestly, TPMS should be mandated by law, IMHO (and I'm a Libertarian).

[ROBERT CROSS]

Originally Posted by out of sight

No WDH for me. That would unbalance my tow vehicle and I would be riding down the street with overloaded front tires and underloaded rear tires. Not a good idea. Not to mention putting unnecessary load on the trailer tires.

I agree 100% with the TPMS however. I just wish Airstream would have supplied the internal sensors. Now I am stuck with external sensors or having to go thru the hassle of pulling all my tires off. Honestly, TPMS should be mandated by law, IMHO (and I'm a Libertarian).

And you do have weight tickets substantiate your 'unbalance'?

A 2500 TV being thrown out of 'balance' by an AS with a WD hitch, properly set up is a bit hard to imagine.

Bob
🇺🇸

[out of sight]

Originally Posted by AirMiles

Same as others stated above, when 1020# is added my F250 Diesel's ball, 420# comes off my front axle and 1440# is added to my rear axle. The axle weights flip-flop from 4820# front and 3840# rear to 4400# front and 5280# rear.

Then I use a weight distribution hitch to return my axles to an equal front/rear weight of 4760#. Equal weighting my axles works best for my truck, the same as it does for Gypsydad. Here is a link to my scale tickets documenting the above results: http://www.airforums.com/forums/f464...ml#post2217820 . I'd suggest going to a scale to see what adding your Airstream does to your truck's axle loads.

You have an F250 which by your numbers has a F/R distribution of 56/44. A Ram 2500 is 62/38 unloaded. A 900 lb ball load, without wdh, brings me to 51/49. almost perfect. But I'm glad you are striving for 50/50, as do I.