Truck bounce

[CamperWill]

So we recently replaced our Envoy with a Tundra and towed with it the first time the other day. The ride was pretty bumpy on the way to the campground (60mph) but was fairly smooth on the ride back (40mph).

The camper is a KZ Sportsmen 242SBH with a GVWR of 6000lbs. The truck is within all the ratings (payload, gcvwr, etc). We are using the same Reese Dual Cam hitch we used with the other tow vehicle but reconfigure it for the truck. The trucks front axle is at the same height it was at before hooking up and the rear sank by 1". The camper is almost level while hooked up (maybe 1/2" off). The bars are rated at 800 lbs.

I'm not sure if it matters but on the Reese DC instructions it states that the top of the ball should be 3/4" to 1" higher then the top of the coupler when unhooked which was not possible. My options were either 2" higher or the same height as a coupler, we went with the same height.

The picture below was taken while being on a slight incline.

Moderator edit to re-size picture to forum recommended limit of 640px maximum width.

[mkirsch]

While weighing is the most accurate way to get it right, measuring the front ride height at the fender wells will get you close enough.

It takes X pounds to compress the suspension Y inches. If you know the inches, you don't need to know the pounds. Simple physics.

If this hitch worked fine with the previous tow vehicle, it's fine for this tow vehicle. The TRAILER weight is what dictates the size of the spring bars. You just need to get the settings right.

[CamperWill]

Thanks everyone! Unfortunately there are not any open weigh station near us. The tundra manual says to return the front axle to the same weight and if unable to weigh then return to the unhitched height.

The bars worked fine on the Envoy so I don't think they are underrated. I'm thinking more head tilt may help since it does seem to be nose up 1/4" or so.

[BenK]

Suggest you familiarize yourself with the goal of all these dials, knobs
and adjustments...

The goal is to have the setup as close to correct for 'your' TV & trailer

TV manual will tell you how much to WD from the rear axle over to the
front axle. The old rule of thumb no longer applies, as the TV OEMs
have vary different suspensions these days

Some will say return front height to what it was before hooking up. Some
will say to get withing 1/2" higher, etc, etc, etc, etc

The trailer tongue should be level at it's highest pointing and I
prefer pointing slightly down

Unless you know the loaded trailer tongue, you will only be guessing
So best to go out and weigh the setup axle by axle. WD tensioned and
untensioned

Then know what each dial/knob/etc adjustment does and what for

Have seen newbies and even some old timers go in circles to find
that their tongue weight was really much too low/high and/or that
their pointing was too high all along

Good luck

[goducks10]

Looks like you need stiffer spring bars, more head tilt or grab more links.
Measure the front fender unhitched and then hitched without spring bars attached.
You need to be 1/2 the distance or less of the difference between the two numbers.
i.e if you have 38" unhitched and 40" hitched w/o springs bars then you want to be 39" or less. But no less than 38"

[mkirsch]

With only 1" of rear sag hitched, you may have an issue of TOO MUCH weight being transferred to the front end.

All these IFS pickup truck suspensions are similar, so I'd expect the Tundra to have "jounce bumpers" like most of the other trucks do. These jounce bumpers are essentially bump stops that engage at unloaded ride height and prevent the front suspension from compressing any lower.

No matter how much tension you put on the WD bars, the front end will NOT sink below unloaded ride height. So, you may think you've got it nailed spot-on, but you could be way overdoing it.

Try adjusting the bars so you only get 1/2 to 3/4 of the way back to stock ride height and see if that's any better. 1/2 is what manufacturers recommend these days.

Don't worry about rear sag. 2" just gets the truck back to level, and it looks like your trailer is riding nose-high anyway.

[Bob_Olallawa]

Take the truck and trailer to a scales and get the front axle of the truck closer to the before trailer weight. Sounds like either the bars are not rated high enough (but they were fine with the other rig?) or not enough weight being sent back to the front axle of the truck. Trailer should be level or slightly lower in front when hooked up.

[nineoaks2004]

My Pickup got a little bouncy , I changed the shocks, problem solved

[CamperWill]

BenK wrote:
Am confused if the manual says that.

The coupler sits on TOP of the ball, so how can it be hooked up if it
is 2" higher than the top of the ball?

Sorry, that was referring to before hooking the trailer up. The manual calls for the ball to be set higher then the coupler to account for the vehicle squat once it's hooked up.

[BenK]

CamperWill wrote:
So we recently replaced our Envoy with a Tundra and towed with it the first time the other day. The ride was pretty bumpy on the way to the campground (60mph) but was fairly smooth on the ride back (40mph).

The camper is a KZ Sportsmen 242SBH with a GVWR of 6000lbs. The truck is within all the ratings (payload, gcvwr, etc). We are using the same Reese Dual Cam hitch we used with the other tow vehicle but reconfigure it for the truck. The trucks front axle is at the same height it was at before hooking up and the rear sank by 1". The camper is almost level while hooked up (maybe 1/2" off).

Tongue pointing is component in whatever problem you are reporting/asking about...

Trailer tongue should be level at its highest pointing and I prefer
pointing slightly down.

If it is 'bouncy', then more to do with the TV's suspension than
pure WD. WD does contribute and has to do with the bar ratings vs actual
tongue weight in reference to the bar ratings *AND* how much the
bars are tensioned

Generally, sounds like the bars are either under rated for the actual
tongue weight, and/or are not tensioned enough

Another is the dampening system of the TV. Tires and shocks the main
components of that. Higher PSI and/or stronger/stiffer tire sidewalls
and/or higher rate shocks helpful in solving that

I'm not sure if it matters but on the Reese DC instructions it states that the top of the ball should be 3/4" to 1" higher then the top of the coupler which was not possible. My options were either 2" higher or the same height as a coupler, we went with the same height.

Am confused if the manual says that.

The coupler sits on TOP of the ball, so how can it be hooked up if it
is 2" higher than the top of the ball?

snip...

[CamperWill]

donn0128 wrote:
If your using the exact hitch setup, there is your problem. It seems you need yo reset your hitch setup. Also different wheel bases will create different loaded ride characteriatics.

As you will see in the original post, we did reconfigure the hitch for the truck (height and tilt).

[donn0128]

Still feel it is setup problem.