Is my Trailair air bag too small?

[GarryH]

I have an '05 Landmark with a trailair air bag---it has a 5500 watt generator in the front and I recently added a washed /dryer combo---since then I have had to put about 100 lbs of air in the bag to keep it the right height
it is a 21,000 lbs hitch and I think the trailer weight would be around 12,000 lbs
I have compared the air bag to other 5th wheels and discovered that this 5th wheel has a 7 inch diameter bag compared to other 5ths that have a 9 inch bag
is it possible to put the bigger air bag in and run it at a lower psi ??
and if so where is the best place to buy a 9 inch air bag
Thanks

 

[jnbhobe]

Re: ATF: Landmark - trailair air bag too small???

I don't know where you can buy it other than Lippert, but I have heard of people changing the airbag for more cushion.If its a firestone bag you may try their website.

 

[jimtoo]

Re: ATF: Landmark - trailair air bag too small???

I think you will need the same amount of air pressure, you will be lifting the same amount of weight. On my 3055 I always had to run about 95-100lbs pressure.

 

[Lance & Jo]

Re: ATF: Landmark - trailair air bag too small???

We have the 9 inch cushion, it was provided by Lippert at the 2011 ralley and runs normally at 80lbs. Looks easy to replace although I learned when I had to take the shock off to repaint last summer that the hinged piece is deceptively heavy. Believe there was an earlier thread last year where someone found the air bags on line but Lippert would be a sure bet.

 

[jbeletti]

Landmark - trailair air bag too small???

Garry,

Your 2005 Landmark is more likely to weigh around 16,000 pounds. Your pin weight with the generator and washer/dryer is likely to be close to 4,000 pounds if you've loaded up your basement like I do

In the past, when I've used the Trailair pinbox on my loaded Landmarks, I ran about 110 PSI in the bag. So I think you are on track with the 100 PSI you're running.

As to the larger bag issue, Heartland will not be able to answer that one. Go right to the manufacturer of the pin box. Give them your pin weight. If not known, then use 3800-4000 as your estimate. Lippert now owns Trailair. Contact them on Monday and circle back to this thread to let everyone know how you came out.

Note: We'll move this thread into the Trailer Hitches and Pin Boxes forum.

 

[GarryH]

Thanks for the reply----I am currently in Corpus Christi, Texas on the way back to BC, Canada---if I get a chance I'll look for a weigh scale and see what my weights are
Thanks again

 

[jbeletti]

Thanks for the reply----I am currently in Corpus Christi, Texas on the way back to BC, Canada---if I get a chance I'll look for a weigh scale and see what my weights are
Thanks again

Garry,

When you get weighed at a truck stop scale, do 2 weighs. One with the truck and trailer on the platforms. The combined weight of both platforms will be the combined truck/trailer weight.

Then, tell the scale person you are doing a second weigh. On the second weigh, disconnect the truck and pull it off the scales. The weight you will get will be the trailer only weight. Note the trailer tires and front jacks may be on different scale pads and you'll have to add those 2 weights to get the complete trailer weight.

Been many years since I used a CAT or similar scale so my directions may be off a bit. In this case, you are trying to come up with pin weight to give to Lippert for bag sizing. To calculate this, you need to subtract the weight of the truck alone (unhitched) from the weight of the truck weight when hitched. That difference will be your pin weight.

Smarter people than I on this will weigh in with a finer point on this (thank goodness!).

Jim

 

[GarryH]

Re: Landmark - trailair air bag too small???

Hi Jim
did all the numbers---found out that the pin weight of the 5th empty is 4168 lbs ---the pin weight of the 5th loaded was 5317 lbs.
the 5th wheel empty is 15345 lbs----the loaded weight was 17017---lesson learned ---don't take so much STUFF
Anyway do you think TrailAir will suggest I get the larger air bag---haven't called them yet----I'll let you know what they say
Garry (email suegar2@gmail.com)

 

[jbeletti]

Garry,

That pin weight sounds high. Can you list all your figures so someone else here can go through them too?

 

[marvmarcy]

Re: Landmark - trailair air bag too small???

Hi Jim
did all the numbers---found out that the pin weight of the 5th empty is 4168 lbs ---the pin weight of the 5th loaded was 5317 lbs.
the 5th wheel empty is 15345 lbs----the loaded weight was 17017---lesson learned ---don't take so much STUFF
Anyway do you think TrailAir will suggest I get the larger air bag---haven't called them yet----I'll let you know what they say
Garry (email suegar2@gmail.com)

These pin weights seem quite high, and if accurate, you need the large air bag. You may also be overloading your truck. Your stated pin weights are what I would expect for a 20,000+# fiver.

 

[porthole]

The weight listed in your last post sounds extremely high.
But to answer your first question, yes, a 2" larger diameter air bag will carry the same amount of weight with less pressure.

That is the reason some people (myself) prefer the AirLift brand of truck airbags over Firestone. For a given application many of the AirLift bags are a bit bigger.

I have compared the air bag to other 5th wheels and discovered that this 5th wheel has a 7 inch diameter bag compared to other 5ths that have a 9 inch bag is it possible to put the bigger air bag in and run it at a lower psi ??

For an example look at this literature.
I don't know how current this PDF is, but it was when I added air bags to the GMC.

 

[jmgratz]

Remember air bags on the truck do not increase the trucks load carrying capacity, they only allow the leveling of the truck. If you pin weight is correct then I would suggest you check what you are carrying in the front closet and in the basement. It might be possible to redistribute the load to lighten the pin weight.