Hard Ride in Dually

[RonS]

I have a 2004 4x4 Chevy Crew Cab dually with Duramax and I'm getting a very hard bucking ride, both when towing 36TK3 Mobile Suites and when running empty. I put on firestone air assit bags even though I did not need them hoping that they would help the ride, they did not do much if anything, and I kept adjusting the air pressure, with no good results. Next step was new shocks went with the Rancho 5100s, and in my opinion they were the same as stock. Should have maybe gone with the bilstens, but to late now. Next step was lowering air tire pressure to 65lbs all six new Michelin LTX M/S tires, still pounds my back.
Does anyone have a FIX ???

[wingnut60]

Air bags will do nothing for unladen ride, only for loads. They may even make it worse since there has to be some air in the bag even when unloaded. Do you need all of the Chevy capacity? How about taking a spring leaf out? Take it to a spring/axle shop and ask them about it.

[hitchup]

Is this at one particular speed range?

We would experience some bucking when going much over 62 mph pulling with our previous TV, 2005 Chevy 3500. That was without any changes to the TV, but Suite does have Trailair pin box. Haven't experienced the problem with the F450.

[RonS]

Yes it does it at all speeds both towing and running empty. I also have the trailair pin box and trailair center point air on the 5th wheel.
No I did not need the air assist on the dually, but wanted to try it before I messed with the springs.
Called Dale at Trailair this morning and he said to try more air in pin box, have been carring 87 lbs will bump it up next trip out.
Maybe I'm expecting too much for the ride in the dually, had 2500HD single rear wheel last truck, and got a much better ride when towing. When running empty if I wanted a better ride I just put some weight in the box. Also had Bilstein shocks and a smaller 5th wheel.
Thanks for the replies.

[MDTdriver]

My truck has 12,500lb air ride bags in rear, with Michelin 19.5 duel tires run at 75lbs min. presure by MFG for 12.600lb. carry wt.
I run 55 to 60 lbs. in my Trail Air pin box. with a pin wt of 3,000lbs. for 5er. Your 87 lbs maybe to high.
Just a thought.

Larry & Kathy

[billr]

Ron,

I didn't know there was a set pressure for the pinbox? I never check ours, just set it to the arrows and thats it. With it set at the pressure you mention, is that what it takes to line it up?

The empty Dually ride is a rough one for sure, but is usually better when loaded. A few things to check (you may have already done this), is the trailer attitude level as well as the truck? If the truck is too high in the rear the springs may not be doing their job, and if the trailer is too high in the front, you may not be transferring enough pin wt fwd to allow the trucks suspension to work. A MS should have plenty of pin wt, but worth a look anyway.

The more air you run in the truck's rear airbags will make the ride harder. Run just enough when loaded to have the truck level.

It's all a bit of a balancing effort to get the hitch and pinbox heights, airbags, and trailair box set to the right height.

Cheers,
Bill

[RonS]

Thanks for all the replies. This is what I did - Removed all the stoppers/brackets for the overload springs, as when hooked up for towing the overloads were in play, but back of dually still too high. This gave me mor flex and dropped the rear a little. Then I put 23 lbs of air in my air assist bags, and this helped when running empty. as now rideing on air and not the rear springs. When hooked to trailer without adding any more air to the bags it went to 40 lbs of pressure, truck and trailer now much more level. I think it helped tame down the bucking ride. Only went a couple miles for the test yesterday, but tomorrow will give it a real test with a few hundred mile trip.
If it dont work I can put all back the way it was, and only out my labor. Does anyone see a saftey issue with removing brackets??

[Charlan]

Had the same problem, added more weight to front of fiver ( filled water tank half full) no more bucking.