Issues Towing with a 2500 suburban

[thinder]

OK here is where I sit. I just sold my 99 K2500 Suburban and bought a 2013 Suburban 2500.

It took forever to get the old suburban to tow right but i did finally get it dialed in. I have a Husky Centerline WD sway control hitch.

Well on the new suburban the factory receiver is really high. Too high to use my old drop bar so I bought a new one. I bought the longest drop I could find and Its still about 2" higher than trailer level. Guess what: it has noticeable sway when vehicles pass me. This didn't happen on the old suburban and doesn't happen on my dodge dually (that I don't use WD on at all)

Ive increased spring bar load and that didn't seem to help, and possibly made it worse.

I'm wondering if taking the load off of the front set of tires on the trailer is making the rig more susceptible to sway when cars pass. And in that case would I be better off lowering spring bar tension and letting the trailer sit more nose down at the expense of the suburban sitting nose high?

Just for the info: Suburban is factory height, 265/70r17 E rated tires at 75Psi trailer is an '86 31' excella at 7500# loaded

[Countryboy59]

Post a pic of the set up, that may help. Have you towed without the WD?

Only problem I had with my 2500 suburban (diesel) was slow traffic in my way.

[dznf0g]

Nose up definitely makes the rig more susceptible to inputs from wind and passing trucks, etc.

Here is the shank I used for that generation of GM SUVs, although your 3/4 ton may be a bit higher and you don't say what drop you did purchase. I honestly cannot recall if I used all the length of the drop shank on the 1/2 tons, or not.

[PKI]

Get the right shank (have one custom built if necessary) or reinforce and lower the receiver. If the rig is not level, the coach axles will not be equally loaded.

TV tires sound good, so tuning may require an upgrade in the damper components, if getting the rig level does not significantly improve your stability.

Might weigh the rig on a CAT scale to get a baseline and validate what you have. If you have weights from prior rig, that comparison should be enlightening.

One additional thought that likely has nothing to do with anything, but worth considering. An 80's coach has seen a lot of years, sitting if not traveling. The axles may have settled enough to make a new set viable to help level the rig. Costly, but if your girl is going to have a long life with your family, maybe.

Good luck with your investigation, data collection and testing. Pat

[JayTheCPA]

Looks like I have relevant experience on all counts in terms of TV and trailer.

Unless I am missing something, tension on the W/D bars do not play much into sway from passing vehicles when the ball height is correct. Does ironically seem like there is still not enough weight on the ball though.

Is the '13 Burb a 4WD like the '99? Not exactly sure how this effects the sway scenario, but if it is 2WD, that might play into the equation as IIRC the nose on the C2500's naturally sit lower than the K2500's which have higher fronts (and appear level from a front / rear perspective). The C2500 will have less up-front weight compared to a K2500 as well.

As others mentioned, do not recommend having either the trailer or Burb out of alignment in terms of wheel / axle loading as that can spell bad Ju-Ju.

Have pulled my '88 33' (about 7K# loaded) with tandem axles using a '12 and a '99 K2500 Burb. And, Yes, the newer 3/4 ton Burb's receiver is a good 5" higher than the older 3/4 ton GMT400 Burb's. So far, I found the higher ball height only caused the trailer's rear to drag on occasion. Did not run into an issue with sway even though I have not gotten the ball height down to the recommend 19" yet. Having an anti-sway brake probably helps. Overall, both generation of Burbs pull about the same and all I am doing is moving the hitch from one vehicle to the other.

Toward getting my trailer's ball height with the '12 Burb down to the recommended 19", I am considering a Roadmaster 'Hi-Low' hitch with either the 4" or 6" adjustment. From what I am seeing, the Hi-Low hitch will cause an extension to the trailer's rigging (electric cord, chains, and break-away) where I am not seeing that will impact the load leveling or anti-sway setups.



Aside, consider having the computer on the '13 Burb checked for updates if not recently done. When this was done on the '12 Burb last year, we found that it was 2 generations behind and it immediately got a 2mpg improvement while towing with the A/C (as calculated by hand) with zero other changes.

[bwoodtx]

Here is where I would start:
Set trailer ball height at Airstream recommendation(ball heights on website)
Set hitch ball at this height(change shank if necessary)
Set WD bars to return front wheel well to within 1/4" of unloaded height.

You can tweak it from there.

[thinder]

Thanks for all the replies. On my center line TS hitch the WD bars also perform the duty of sway control via friction. I took this thing to an RV dealer to get the drop I have and they "set it up." they sold me the drop that I currently have, approx. 7 1/4" from top position to bottom and claimed that's all you can get woihout going custom. that's what I get for not doing it myself I guess. but anywayI found a longer drop on etrailer that should get me 3" more. That should get me to my 19"

On the Axles, they still show some positive angle so I've got a little life left. I've done axles on other Airstreams so I'm not opposed to it and I didn't think it was terribly expensive.

Ill post results when I get the new setup.

[thinder]

Yes its a 4wd.

How do you check the computer? EFI live or Autoenginuity? Ill probably have an aftermarket tune flashed. 2Mpg is HUGE in these things.

Originally Posted by JayTheCPA

Looks like I have relevant experience on all counts in terms of TV and trailer.

Unless I am missing something, tension on the W/D bars do not play much into sway from passing vehicles when the ball height is correct. Does ironically seem like there is still not enough weight on the ball though.

Is the '13 Burb a 4WD like the '99? Not exactly sure how this effects the sway scenario, but if it is 2WD, that might play into the equation as IIRC the nose on the C2500's naturally sit lower than the K2500's which have higher fronts (and appear level from a front / rear perspective). The C2500 will have less up-front weight compared to a K2500 as well.

As others mentioned, do not recommend having either the trailer or Burb out of alignment in terms of wheel / axle loading as that can spell bad Ju-Ju.

Have pulled my '88 33' (about 7K# loaded) with tandem axles using a '12 and a '99 K2500 Burb. And, Yes, the newer 3/4 ton Burb's receiver is a good 5" higher than the older 3/4 ton GMT400 Burb's. So far, I found the higher ball height only caused the trailer's rear to drag on occasion. Did not run into an issue with sway even though I have not gotten the ball height down to the recommend 19" yet. Having an anti-sway brake probably helps. Overall, both generation of Burbs pull about the same and all I am doing is moving the hitch from one vehicle to the other.

Toward getting my trailer's ball height with the '12 Burb down to the recommended 19", I am considering a Roadmaster 'Hi-Low' hitch with either the 4" or 6" adjustment. From what I am seeing, the Hi-Low hitch will cause an extension to the trailer's rigging (electric cord, chains, and break-away) where I am not seeing that will impact the load leveling or anti-sway setups.



Aside, consider having the computer on the '13 Burb checked for updates if not recently done. When this was done on the '12 Burb last year, we found that it was 2 generations behind and it immediately got a 2mpg improvement while towing with the A/C (as calculated by hand) with zero other changes.

[thinder]

Ok got a longer drop installed. Looks much better. I haven’t towed any distance yet so I’m not sure if anything has improved.