Towing Advice 2015 Tahoe Porpoising

[DieselDrax]

Originally Posted by mopwr4me2003

Here you go love birds, from Air Lift company. This sums it up for the most part.

Weight Distribution Bars and Air Springs.

The downward force of heavy trailer tongue weight causes the front of your vehicle to lighten up and rise as the vehicle pivots over the rear axle. This causes the vehicle’s weight to be unbalanced and steering traction will be lost. This is a dangerous situation because of the lack of control and fishtailing of the trailer.
The fix…

Weight distribution bars used with Air Lift air helper springs (also called air bags) provide maximum stability and control of your towing vehicle and trailer. Air Lift air springs provide load assistance for your sagging vehicle, and the weight distribution bars redistribute the load and balance your vehicle.
In many situations, heavier weight distribution bars are used to remedy weak suspensions or when additional cargo in the vehicle causes it to sag. Doing so will result in an unbalanced vehicle, excessive tire wear, and an uncomfortable ride. Add and adjust the correctly sized weight distribution bars to solve your weight balance problems and then add and adjust Air Lift air helper springs to fix your suspension problems.
Finding the correct pressure…

Start by selecting the correct distribution bars. The bars must be rated for the tongue weight of the trailer (i.e., 500-pound bars for a 500-pound tongue weight). With the vehicle UNLOADED, take reference measurements at the front and back of the vehicle to the ground. Then connect the trailer and start loading the bars one chain link at a time, keeping the links equal on both sides. As the load on the bars increase, the rear of the vehicle will come up and the front will come down. When the front and rear of the vehicle are as close to the reference measurement as you can get (within ½” at the front), the bars are tensioned correctly. When the bars cannot be adjusted tightly enough to achieve similar or identical vehicle-height reduction, add air to the air springs to bring the vehicle back to the correct height and balance.
When adding cargo to the vehicle or trailer, do not compensate for inadequate suspension by using higher rated bars, or readjusting the bars, as this will cause for an unbalanced vehicle. Use additional air pressure in your air springs to bring the vehicle back to the correct height.
Fine tuning vehicle stability can be accomplished by an adjustment to the air pressure in 5 PSI increments until the desired “feel” is achieved. Adding air may require readjustment of the bars.

Yup, that last sentence says it all.

Air Lift says adding air "may" require readjustment of the WDH, and let's be honest if the vehicle height is being changed more than a fraction of an inch then the WDH WILL need to be readjusted.

Equal-I-Zer says adding air after connecting the WDH will cause the WDH to be misadjusted and to adjust the WDH AFTER adding air.

etrailer.com says "When you use the two systems together you will want to air up the bags first before you setup the WD system."

Air the bags first and then adjust the WDH. Always.

[jaherbst]

Originally Posted by mopwr4me2003

Here you go love birds, from Air Lift company. This sums it up for the most part.

Weight Distribution Bars and Air Springs.

The downward force of heavy trailer tongue weight causes the front of your vehicle to lighten up and rise as the vehicle pivots over the rear axle. This causes the vehicle’s weight to be unbalanced and steering traction will be lost. This is a dangerous situation because of the lack of control and fishtailing of the trailer.
The fix…

Weight distribution bars used with Air Lift air helper springs (also called air bags) provide maximum stability and control of your towing vehicle and trailer. Air Lift air springs provide load assistance for your sagging vehicle, and the weight distribution bars redistribute the load and balance your vehicle.
In many situations, heavier weight distribution bars are used to remedy weak suspensions or when additional cargo in the vehicle causes it to sag. Doing so will result in an unbalanced vehicle, excessive tire wear, and an uncomfortable ride. Add and adjust the correctly sized weight distribution bars to solve your weight balance problems and then add and adjust Air Lift air helper springs to fix your suspension problems.
Finding the correct pressure…

Start by selecting the correct distribution bars. The bars must be rated for the tongue weight of the trailer (i.e., 500-pound bars for a 500-pound tongue weight). With the vehicle UNLOADED, take reference measurements at the front and back of the vehicle to the ground. Then connect the trailer and start loading the bars one chain link at a time, keeping the links equal on both sides. As the load on the bars increase, the rear of the vehicle will come up and the front will come down. When the front and rear of the vehicle are as close to the reference measurement as you can get (within ½” at the front), the bars are tensioned correctly. When the bars cannot be adjusted tightly enough to achieve similar or identical vehicle-height reduction, add air to the air springs to bring the vehicle back to the correct height and balance.
When adding cargo to the vehicle or trailer, do not compensate for inadequate suspension by using higher rated bars, or readjusting the bars, as this will cause for an unbalanced vehicle. Use additional air pressure in your air springs to bring the vehicle back to the correct height.
Fine tuning vehicle stability can be accomplished by an adjustment to the air pressure in 5 PSI increments until the desired “feel” is achieved. Adding air may require readjustment of the bars.

Exactly what I was trying to say. Perhaps not as well as said here. If in doubt if you need Air Bags, install the WDH and drive it awhile. When you porpoise or just need a little rear end height add the air bags but use them sparingly and let the WDH do most of the work. Every Trailer and Truck combo is a little different and it is up to you and a little on road experience to decide what to change if any.

Jack

[davetorre]

Originally Posted by jaherbst

Exactly what I was trying to say. Perhaps not as well as said here. If in doubt if you need Air Bags, install the WDH and drive it awhile. When you porpoise or just need a little rear end height add the air bags but use them sparingly and let the WDH do most of the work. Every Trailer and Truck combo is a little different and it is up to you and a little on road experience to decide what to change if any.

Jack

Thanks,

Installing a pair of timbrens today on the Tahoe to see if that helps. Also checking tongue weight and adjusting WDH.

[jaherbst]

Originally Posted by davetorre

Thanks,

Installing a pair of timbrens today on the Tahoe to see if that helps. Also checking tongue weight and adjusting WDH.

[SIZE="4"]I think you will be happy with them and they should improve the tow. If it were me I would get the Air Lift that you can vary the air pressure with a bluetooth connection to a small remote handheld in the Tahoe. This will give you the advantage of different settings depending on ride and trailer weight. Once a number is set on the remote auto inflate will occur whenever you start the vehicle to the amount indicated. You will never have to manually inflate again. Of course this system is a lot more expensive but you get what you pay for. (Air lift 5000)

Jack

[davetorre]

OK, so I did some investigating on the WDH, the bars are rated for Max 800lbs
tongue/10,000 trailer weight. After weighing the trailer tongue it is coming in at 825-850 lbs loaded.
(no water in tanks) the spec unloaded is 694lbs,
The trailer UVW is 5170 so I suspect with my stuff in the trailer it is near 6000.

Any ideas? does this look correct? are these bars too light?

[DieselDrax]

Originally Posted by davetorre

OK, so I did some investigating on the WDH, the bars are rated for Max 800lbs

tongue/10,000 trailer weight. After weighing the trailer tongue it is coming in at 825-850 lbs loaded.

(no water in tanks) the spec unloaded is 694lbs,

The trailer UVW is 5170 so I suspect with my stuff in the trailer it is near 6000.



Any ideas? does this look correct? are these bars too light?

Yes, bars are too light. The 800lb number is the max tongue weight they are meant for so you need to go up to the next bars.

[thebrakeman]

Originally Posted by davetorre

OK, so I did some investigating on the WDH, the bars are rated for Max 800lbs
tongue/10,000 trailer weight. After weighing the trailer tongue it is coming in at 825-850 lbs loaded.
(no water in tanks) the spec unloaded is 694lbs,
The trailer UVW is 5170 so I suspect with my stuff in the trailer it is near 6000.

Any ideas? does this look correct? are these bars too light?

I'm late to the discussion, but my first question was going to be, "What size WDH kit are you using?".
Porpoising, in my opinion, is usually a symptom of being too near (or over) the weight rating of the spring bars. When you get too close, they act more like springs (bouncy, bouncy, porpoisy) than bars.
5170 dry + 1000 lbs estimate for stuff = 6170 lbs.
6170 * 12.5% estimated TW = 771 lbs
6170 * 15% = 925 lbs
You are obviously somewhere in-between, at 825-850 lbs.

I always recommend adding 100 lbs to your estimated (or actual) TW, in order to determine the size WDH kit, then round up to the next available size. 850 + 100 = 950. So, you need a 1000 lb WDH kit.

Perhaps your brand allows upgrading just the bars. Give them a call to find out.

Don't bother upgrading the tires. That would be to solve a sway issue that the WDH/sway control isn't solving. As long as they are rated for the load, and aired properly, I wouldn't bother until what you have wears out.

And don't bother with air bags. Air bags are for handling payload (over the axle). For TW (behind the bumper) you just need the right WDH components.