Air bags verses chucking?

[Art]

I'm looking for advice and this is the right place! By my signature, I have a GMC 3500 with a 3670RL Montana and TrailAir hitch. I know that I can't eliminate the chucking COMPLETELY but will adding air bags in the truck's rear axle help to eliminate it? (I don't really need it to make the truck level) My wife was in an accident and has a sensitive back when it comes to travel! Thanks!

[boylanag]

Art, Carol had surgery on the vertebrae in her neck and the chucking and bucking was a very painful venture for her. We got the 5th Airborne pin box and now she does not have that problem. It smoothed out the ride considerably. The 5th Airborne has an air bag and a shock absorber so adding airbags to your truck combined with your Trailair should be fine. Good luck - Jim

[sreigle]

Art, I have doubts how much airbags will help since you already have the trailair. As you know, the primary purpose of the airbags is to level the ride. I had airbags on two trucks. I found that with the incab compressor and gauge I could adjust the ride on the fly and that would help the chucking motion. It did not totally eliminate the motion, though.

I suspect since you have the trailair that airbags won't give you any more help.

This might sound oddball to you but it's what we've found. The major portion of the chucking seems to be on concrete highways. Mostly interstates. We find we have far less of this "problem" when we travel US highways. We do sometimes have the chucking on a concrete US highway but far less than on interstates. So, if the chucking is a problem for you and you don't find a cure, you might try avoiding the types of roads that cause the problems. To us the US highways are far more relaxing and enjoyable to travel, anyhow, unless we're in a hurry.

[tbhd2]

We have an 04 3670RL and have added the Mor-Ryde pin box and the Firestone air bags. They really helped but did not eliminate the chucking. Because of worn spring shackles we recently installed the Dexter wet bolt kit along with the rubber cushion rocker arm available through Dexter also and that has helped a lot with the ride in general. A very inexpensive fix and you probably need the wet bolt kit anyhow.

[OntMont]

We have the same truck and trailer as you do with the TrailAir hitch. We also have the TrailAir Equaflex suspension with wet bolts. We can't really say if this combination is better than what you have, but it is something to consider, it is worth it just to get the wet bolts. I don't think adding air bags to the truck would do much for you, but you might explore other shock absorber options. Or how about something like an Orbusform seat cushion?

Some roads are so bad that I don't think there is anything that will help except as Steve suggests, get off them and take the scenic route!

[TLightning]

As noted above, air bags will not affect chucking. Air bags help control up/down motion, the shock on the 5th Abn pin box is to help with the fore/aft movement (chucking.).

[Ishler]

I second tghd2's report, the Mor-Ryde pin box made a huge reduction in the chucking for us. It's design is targeted at chucking.

[Art]

Thanks for all the great input! I will be looking into the wet-bolt system for the trailer.

[Mrs. CountryGuy]

Art,

If you have the Trail-aire, you have the PIN, right?? Al tells me they do not make a hitch (that is the part in the truck, as he has pounded in my head for 5 years, and I am just starting to get it thru my thick skull! )

The Mor-ryde system that Isler is referring to, is a PIN exchange. I cannot see that you would necessarily change out one PIN for another PIN. ???????????????

I have no info on your original question, which is can you add air bags, and will it take out the chuck, but, I was confused, as usual, and thought I would just ask, and clarify what your equipment is,

PIN (on the trailer) ?????????

or

HITCH (in the truck)?????????

(I repeat this daily, as per directions of my hubby, till it spits out correctly! HA HA HA)

[exav8tr]

The Mor-Ryde King Pin has taken out MOST of the chucking on my rig, the rest lets me know I am pulling a fiver. I would think a good combination would be an air ride hitch and a Mor-Ryde king Pin. My opinion, of course....

[dieselguy]

I installed the Glide-Ride pinbox http://www.demco-products.com/Pages/RV/glide_ride.htm on my fiver ... it's design is simple and effective. Easy to install and doesn't effect the ride height of your fiver ... if you order it thru a Hitchhiker dealer, you can save some bucks verses factory direct. Although it does make a huge improvement over the factory pinbox ... it doesn't eliminate 100% of the "chucking".

[Delaine and Lindy]

We had a Trailer Saver Air ride hitch and the Mor/Ryde pin box and suspension, we had no chucking. We will have the TrailAir and equa Flex on our new 5th wheel, will pick it up this week. I may wish we had gotten another Trailer Saver however the TrailAir works on the same principle. We hope it works, don't want to spend so much money on the Trailer Saver. We have went to a B&W turnover ball with the Companion 5th wheel hitch, so I can use the Gooseneck trailer also (Flat bed equipment trailer).

As for air suspension on the Truck it will help very little on the Concrete dividers. The only fix I found for that was Air Ride seats. We had Air ride seats and a Link Air Ride supension in our Chevy Kodiak 4500, it was the best ride of any Truck we have owned. Good Luck with your decision. GBY....

[sreigle]

I have to disagree with the comments that airbag adjustment cannot moderate the chucking. On airbags without the onboard compressor and incab control, that's pretty much true because you cannot adjust the air pressure while underway. But I numerous times smoothed the motion using the incab controls, although I could never totally eliminate the motion. Below is the reasoning.

What I read about the chucking is that while it feels like fore-aft movement and that is the end result, the cause is the up and down movement caused by the truck's suspension reacting to road imperfections, especially the ones spaced to cause rhythmic motions. The rear of the truck goes up over a bump and takes the nose of the fifthwheel with it. This upward motion pulls the axles on the trailer forward relative to the truck axle, creating a smaller distance between truck rear axle and trailer front axle. Then as the truck axle comes off the bump or road strip, the nose of the trailer comes back down, pushing the trailer axles back, relative to the truck axle. This push-pull motion is the fore-aft chucking we feel, especially when there are evenly spaced imperfections that set up rhythmic motions. So the actual cause of the chucking is the up and down motion of the truck suspension reacting to road imperfections. Airbag adjustment while underway can moderate that reaction to the roadway.

That's why I was indeed able to somewhat moderate the chucking by adjusting the airbags on the fly using the onboard compressor and control in the cab.

Our current truck does not have airbags but we do have Rancho adjustable shocks with compressor and incab controls. I can slighly manipulate the motions by adjusting the shocks, but only a little. The airbags did a better job of this. The shocks, on the other hand, made the firm Dodge ride much more comfortable for our old backsides, both onroad and on 4x4 roads. That was my one complaint about Dodge trucks and these shocks have made a huge improvement. I don't think it rides quite like the new Fords and GM's but it's a very comfortable ride.

[Dave e Victoria]

There is a lot in the archives discussing the merits of various hitch combinations with regard to chucking. It is important to say there is no system that will completely eliminate the effect. These are all second order damping systems that offer some help as long as the road isn't too bad. You should also be aware that trailer loading has a potential for helping as well. Make sure you are not overloaded so your trailer suspension is not bottoming out. And, make sure at least twenty percent or more of the trailer weight is on the pin. Finally, be sure the truck suspension is not overloaded allowing it to bottom out. This is one place where the air bags can help by regaining maximum suspension travel.

BTW, we have had the trail air (on our 3295RK) with and without airbags and the Mor ryde (on the Cambridge) with and without airbags. I avoid highway 10 between Houston and New Orleans and Highway 69 between Lansing and Flint.

[mtmy2k2]

We had lots of chucking issues with our Mountaineer. I installed firestone ride rites and it did not make much difference. I added a compressor in the cab so I could adjust on the fly and it helped some. The big difference and what I should have done first was install a new pin box. We selected the Demco Glide Ride hitch and swear by it. There are even times I have to check the mirrors to see if its still there, it's that smooth. On really bad roads you still get some movement but I would say that we've eliminated 90% of it.

[BB_TX]

quote:Originally posted by sreigle

What I read about the chucking is that while it feels like fore-aft movement and that is the end result, the cause is the up and down movement caused by the truck's suspension reacting to road imperfections, especially the ones spaced to cause rhythmic motions. The rear of the truck goes up over a bump and takes the nose of the fifthwheel with it. This upward motion pulls the axles on the trailer forward relative to the truck axle, creating a smaller distance between truck rear axle and trailer front axle. Then as the truck axle comes off the bump or road strip, the nose of the trailer comes back down, pushing the trailer axles back, relative to the truck axle. This push-pull motion is the fore-aft chucking we feel, especially when there are evenly spaced imperfections that set up rhythmic motions. So the actual cause of the chucking is the up and down motion of the truck suspension reacting to road imperfections. Airbag adjustment while underway can moderate that reaction to the roadway.

That's interesting. From what I had read, it was described differently. When the truck hits an imperfection in the highway (bump), the truck slows slightly. That causes the 5er to push the truck. When the truck passes over the bump, then the 5er hits the same bump and the 5er slows slightly, pulling back on the truck. That push-pull motion is the chucking.
Maybe it is a combination of both?

[Dave e Victoria]

BB_TX,
Steve is pretty close to correct. Your explanation is not quite there -- if it were, the effect would be felt in a regular travel trailer but it is not - at least not in the same way.

Chucking comes about because of the geometry of the fiver hookup. The hitch point is above the rear axle.. If you think about the rear axle of the TV being a pivot point, then any up -down at the front of the truck or on the trailer suspension gets absorbed by the lever arm of the hitch above the pivot. It becomes a jerk in the fore aft direction. This is why undulations in the road surface feel like fore aft jerks inside the truck. This geometry deal is what makes a gooseneck almost eliminate chucking --(of course a gooseneck has it's own problems)
Dave

[exav8tr]

Dave and Steve, I heard the same thing from the Mor-Ryde folks and they explained that the hard rubber dampener was designed to absorb this motion. I bought their king pin and installed it myself in western Oregon. I must admit that it eliminated the majority of this chucking, but not all. I have the CW Air Lift adjustable bags on my Chevy but have never thought of adjusting them on the fly to prevent this chucking. For those of you that have the bags, what pressure do you try and maintain on these rotten roads?

Thanks for any and all advice.....

[mtmy2k2]

We usually keep out airbags around 35 to 40 lbs. Our 5er is on the lite side, about 9200 loaded and that works well for us. I suspect that you would have to fiddle with it on your set up to see what worked best.

[Dave e Victoria]

I kept the bags on my 2500HD at 55 to 60 pounds under both the 3295RK and the Cambridge. There was never any problem about forgetting to let them down when unhooking as the truck rode rough at that pressure when unloaded.
Dave