Update 5/2/21 - Bounce and Porpoising - Especially Towing

[norcalboon]

It could be the photo is a little deceiving but it looks like your trailer is a little nose down and the equalizer bars are not level. Try to raise the hitch one notch and ensure the bars are level to the ground when tight. The trailer should also be level to the ground. Do all of that with the trailer just sitting in place on the hitch ball with no load on the truck. Once that is done put the load on the truck and try it.

different photo

 

[Sobro]

My WDH says you measure the height of the rear bumper unhitched but the truck loaded and then hitch up and measure the height again. Adjust the chains on the WDH bars until the bumper height is back to the previous measurement.


But it sounds like you've done similar and are still getting the same result, so you working on your suspension seems to be the solution.

 

[exp500]

Appreciate your input James (and others) - it's been weighed at a scale which I included, 6,420 TT only 13,520 total Gross. Dry tongue weight is listed at 540lbs - and I have the storage in the front loaded with 2 cases of water dead center, and all of our gear so it is easily another 100lbs minimum for a total minimum tongue of 640lbs which is 10% - it's likely even more considering I have two deep cell batteries vs 1 and two 7.5 gal propane tanks up front and also have a 100lb german shepherd in the very back of the Yukon, so it's likely closer to 800lbs or 12%. Don't have much extra stored in the back/middle of the trailer to add weight there.


This is the 3rd Yukon XL I've used to tow this trailer and never had a bounce issue - granted the previous 2 were 1/2 tons but still I'd be surprised if it was just how the WDH is set up or how it's loaded - and as I mentioned I have already moved the shank up and down and adjusted my chain links to several different positions with no change in ride quality. It also rides rough empty with bounce over bumps (but no porpoising without the TT).

I'm not sure your numbers are correct, Thats why it was asked in post8 I believe. You can scale the truck, get F/R weights empty. Attach TT and reweigh with 3 shown- TT , rear axle, front axle of truck. No calculating or guessing on weights using supposed dry weights. For instance carrying 100 gallons of water behind the rear axle. Thats 800# in a bad place. You could very well be correct, But me- I'd want 1200# + on the hitch to test, roughly 25 percent. And also know the distribution= How hard to crank the hitch Bars. 7100# for the truck sounds hi.

 

[fasteddy]

I'm stock ride height

B6 4600 Versus B8 5100 (bilsteinus.com)

So was I. But I still used 5100s....and airbags....they are cheap and I consider them a safety item.
Bouncing is a dampening issue-shock absorbers, meaning compression and rebound aren't working.
So you need shock absorbers front and back and I wouldn't tow a trailer that big w/o airbags....it'll stiffen up the back.
You want to pull the trailer, not have the trailer pull you.
IMO it becomes a safety issue. Bouncing mean weight is moving uncontrolled up and down and it can destabilize/move the vehicle and/or trailer off track.
Get off track on a mountain highway next to a drop and it becomes dangerous really fast.

I knew this guy some years back coming back from laguna seca over the mountains and it was raining.....the trailer pulled him over the cliff.
We had no idea how it happened. They didn't find him until the next day. I hate trailering. Always overbuild the tow vehicle. Be safe.


Check out my yukon! Looks familiar yes?
I miss that thing....the seats were so comfortable, nice and puffy.

 

[fasteddy]

And how long is your trailer? Overall.
In your pictures I have yet to see the end of it. lol

 

[corvette744]

Bag it................

 

[norcalboon]

And how long is your trailer? Overall.
In your pictures I have yet to see the end of it. lol

28ft Tongue to bumber

 

[norcalboon]

So was I. But I still used 5100s....and airbags....they are cheap and I consider them a safety item.
Bouncing is a dampening issue-shock absorbers, meaning compression and rebound aren't working.
So you need shock absorbers front and back and I wouldn't tow a trailer that big w/o airbags....it'll stiffen up the back.
You want to pull the trailer, not have the trailer pull you.
IMO it becomes a safety issue. Bouncing mean weight is moving uncontrolled up and down and it can destabilize/move the vehicle and/or trailer off track.
Get off track on a mountain highway next to a drop and it becomes dangerous really fast.

I knew this guy some years back coming back from laguna seca over the mountains and it was raining.....the trailer pulled him over the cliff.
We had no idea how it happened. They didn't find him until the next day. I hate trailering. Always overbuild the tow vehicle. Be safe.


Check out my yukon! Looks familiar yes?
I miss that thing....the seats were so comfortable, nice and puffy.

View attachment 277273

Understood, I’d be inclined to trust the manufacturer recommendation as they state there is no difference between the 2 besides length to accommodate higher rides. I towed it with my previous 1/2 ton Yukon XL without added suspension just fine. My wife’s Denali pulls it it fine (of course it has air ride shocks). Went to a 3/4 ton for the heavy duty components and really wanted the 4.10 rear end b/c the biggest issue I had with the previous 5.3 w/3.42 was bogging down up hills - never had a sway or bounce or sag problem. Towing power up hills is perfect with 6.0 and 4.10s just need to get rid of this bounce. Appreciate the feedback, may still look into air bags.

 

[norcalboon]

I'm not sure your numbers are correct, Thats why it was asked in post8 I believe. You can scale the truck, get F/R weights empty. Attach TT and reweigh with 3 shown- TT , rear axle, front axle of truck. No calculating or guessing on weights using supposed dry weights. For instance carrying 100 gallons of water behind the rear axle. Thats 800# in a bad place. You could very well be correct, But me- I'd want 1200# + on the hitch to test, roughly 25 percent. And also know the distribution= How hard to crank the hitch Bars. 7100# for the truck sounds hi.

To be comprehensive I plan to re-weigh and get axle weights this time. Note the total Gross of 13.5 was fully loaded and the trailer was unhitched and weighed separate. Thanks for the input I’ll keep providing updates until I get it figured out.

 

[norcalboon]

Bag it................

Without having looked it up - where do the airbags go with the leaf springs In back? Had previously considered on my 1/2 ton but those went inside the rear springs. Thanks for the input.