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

[Mr Dan]

Bro,
You have the right ride....6.0L and don't denalis have auto-leveling.

I bought this sub a few years back to go on Jet-Ski camping trips (where they don't have hotels).
6.2, 10spd and it hauls butt.
Its only a 1/2 ton but it has auto leveling and when I realized it could easily tow my 25ft trailer with another car in it (about 8Klbs) I sold
the 2500 RAM cummins, which just sat around waiting for a tow job. I sheet you not, the sub tows just as good as the RAM did
Gets a little worse gas mileage when towing (10 vs 13), but when not towing it gets like 27mpg on the highway. GM-techno-magic.

View attachment 277556

I ripped the seats out and slid in a queen so I can cool down and sleep back there.
I'd rather camp with A/C and Bose than pitch a tent...especially when its 95 at night.

View attachment 277557

And I fit this bubble insulation stuff from Home Depot in the windows for cooling and privacy.
It works really good....except I don't have bug screens (to crack the windows)....still have to figure that one out.
View attachment 277558

But its only a 1/2 ton and it tows really well.

 

[Mr Dan]

For camping in our NBS we us a roll of lightweight nylon screen and magnetic tape. After a little adjustment, instant window screens.

 

[BigDogYJ]

I’ve got an 04 2500 XL that I tow different trailers pretty regularly 1500-7500#. The heaviest was my car/equipment trailer with an 07 2500HD crew cab pickup. Probably weighed near 10k as my trailer unloaded is 2500lb. No porpoising effect that I recall. It can bounce at times in rough highways but nothing uncontrollable or bounce out of seat effect The only change I’ve done to suspension is adding the road master active suspension for leaf springs. It’s a coil spring that mounts across the top of the leaf and it’s adjustable. Works great. I also run bilstein 5150 reservoir shocks f/r. Rides stiff unloaded but drives like a dream when loaded up. Check hitch bolts and make sure everything back there is tight. And again level and 12-15% tongue weight is key.

link to Roadmaster suspension: https://activesuspension.com/products/kits/1984-2012-chevrolet-2500-suburban-suv/


We are looking to get a 28’ TT in a couple months. It supposedly has a 650# dry tongue weight and 9600# gross. I’ve already ordered the hitch (ProPride 3p). So I’ll likely have some first hand experience with a TT. Keep us informed as you work through it.

 

[Matthew Jeschke]

Somebody already posibly answered this anx maybe your symptoms are something else....

You want a damper (shock) that is matched to your spring pressure. If you have a shock spec'd for 1500 chassis spring then you will be underdamped and bouncy. The shock won't have enough dampening (won't be tuned) to filter out the oscillations / bumps your springs expirence. Conversely if too strong / overdamped will feel like all the bumps transfer through to the cabin.

The remaining things, I have no experience with, but if your trailor / hitch is weighted wrong you will get feedback from the trailor to the front end of truck, possibly enough to break the tires loose. I have seen accidents where this happened.

I desined a couple racecar chassis back in the day. We had long talks about this sort of thing. I am sure you just need a minor tweek then will be riding great

Sent from my SM-A505U using Tapatalk

 

[fasteddy]

For camping in our NBS we us a roll of lightweight nylon screen and magnetic tape. After a little adjustment, instant window screens.

You should post a picture of that....I'd like to see that.
Please continue in the "interiors" section so we don't step on his thread.

 

[fasteddy]

I’ve got an 04 2500 XL that I tow different trailers pretty regularly 1500-7500#. The heaviest was my car/equipment trailer with an 07 2500HD crew cab pickup. Probably weighed near 10k as my trailer unloaded is 2500lb. No porpoising effect that I recall. It can bounce at times in rough highways but nothing uncontrollable or bounce out of seat effect The only change I’ve done to suspension is adding the road master active suspension for leaf springs. It’s a coil spring that mounts across the top of the leaf and it’s adjustable. Works great. I also run bilstein 5150 reservoir shocks f/r. Rides stiff unloaded but drives like a dream when loaded up. Check hitch bolts and make sure everything back there is tight. And again level and 12-15% tongue weight is key.

link to Roadmaster suspension: https://activesuspension.com/products/kits/1984-2012-chevrolet-2500-suburban-suv/


We are looking to get a 28’ TT in a couple months. It supposedly has a 650# dry tongue weight and 9600# gross. I’ve already ordered the hitch (ProPride 3p). So I’ll likely have some first hand experience with a TT. Keep us informed as you work through it.

2500 with an LBZ, very nice!

 

[iCajun]

No help other than what the others have mentioned. I have about the same vehicle, 2005 2500 8.1L, all stock except for the H2 wheels and somewhat oversize tires. Have towed trailers from aluminum snowmobile to 10k travel trailers and I haven't had porpoising. Tire pressure and tongue weight is generally all there is to adjust. Good luck.

 

[wildcatgoal]

Um, is it me or are the axles on that trailer literally dead length center instead of slightly back behind center? Last time I towed a trailer where the wheels weren't oriented more backward was a car trailer and I had to fight the damn thing teeter tottering the whole time which was causing the front end to effectively bounce. The guy built/welded the trailer himself... evidently wrong or maybe for an application that had far more weight on the front of the trailer than I had. When I switched trailers to a factory design, towing was smooth and flat.

 

[73Vetteman]

I have found that porpoising is a problem related to the equalizer bars. I suspect you need stiffer rated bars. The trailer and vehicle should move up and down together as a unit over small dips in the road rather than pivot at the trailer ball. Your existing bars were probably adequate for your shorter wheelbase Yukon but the leverage on the bars is increased by the longer wheelbase of your XL.

 

[norcalboon]

Update 5/2/21

Front shocks were shot - replaced with the Bilstein 4600s, also replaced the first Timbren’s with the replacement pair they sent. So far much better, will dial in WDH next weekend but feel these 2 items will go along way to fixing the issue. Pics for reference - original shocks vs. replacements and the new vs. old Timbrens. Will complete update after getting the WDH set up and giving it a test drive next weekend. Thanks again for all the input.

 

[bigdog9191999]

alright, i will ad a couple pennies to this scenario. i have towed with many different vehicles mostly cars and equipment, not much camper yet. (the camper pictured was of my aunts, i was helping to move after she lost her truck) i have pulled the same combination with most of them so have an apples to apples load comparison amongst them. and with varying loads on them from light to maybe a little more than it should be. but bottom line is they all had basic control and handling similar to each other. a trailer with a load is a trailer with a load ( when loaded similarly)

sure there are stiffness differences among them but that is more a comfort thing than control and handling in my experience. the one that made a very notable difference is a dually and its ability to not let a trailer have as much "wiggle" input as the rear is more side to side stable.

the only times i have had issues was usually due to improper loading/balance or something mechanically wrong with truck or trailer.

i am guessing your issue lies in the truck esp being the trailer is confirmed decent with other vehicles.

in a few days i plan to make the longest haul with my burb since i got it ( not the heaviest, but longest) and i have does this trip several times with varying loads and have about 98% certinty of what to expect. (aside form the power bump of 8.1)

 

[iCajun]

Are those the factory type electronic shocks?

 

[norcalboon]

Are those the factory type electronic shocks?

Nope, regular shocks on this one.

 

[iCajun]

I thought all 2500s had them. Autoride.

 

[fasteddy]

Update 5/2/21

Front shocks were shot - replaced with the Bilstein 4600s, also replaced the first Timbren’s with the replacement pair they sent. So far much better, will dial in WDH next weekend but feel these 2 items will go along way to fixing the issue. Pics for reference - original shocks vs. replacements and the new vs. old Timbrens. Will complete update after getting the WDH set up and giving it a test drive next weekend. Thanks again for all the input. View attachment 278168View attachment 278169View attachment 278170View attachment 278171

Yeah.....those shocks look totally and literally depressed. That would cause bouncing in the front.

Those Timbren things look cool...very easy to install. Is there a spring rate associated with those?