Help With Rear Suspension For Trailer Towing

There's a lot of things to take into consideration. I'll start off first by saying your local 4x place is stuck in the 90's. Rancho's are a joke. Airbags on the other hand can be exceptionally helpful...but the real answer is "it depends." With that...let's take a better look at your setup.

So lets talk GVWR. You're at 7200 lbs with a curb weight of around 5650. That puts your payload at 1550 lbs. Lets assume 25 gallons of gas, which is roughly 156 lbs. That brings you down to 1394. Let's assume 2 adults riding inside at 150 lbs each, that's now down to 1094. Remove your 900 lb tongue weight and you're left with 194 lbs. Now the reason I went through this math exercise to point out how LITTLE weight you are left with to put into the bed. So hauling this monster trailer, my question to you is what's in the bed? Anything more than 200 lbs (or adding two more adults) and you are exceeding the GVWR of the truck. Remember, even though the tundra can pull 10k lbs, at the end of the day it's still a half ton truck and has half ton payload.

Next...you mentioned you have a WD hitch. I've seen it time and time again where people claim they are using a WD hitch and still have problems. Posting a picture normally clears this up...and identifies that the hitch is setup incorrectly. Several things to take into consideration:

• When a WD hitch is installed properly, the suspension should drop EQUALLY both on the front and rear. Measure from center of the hub to the bottom of the fender unloaded and loaded, both front and rear, and do some math. Ensure that at most, the rear should drop no more than 1" more than the front.
• If the rear is dropping significantly more than the front, then either the ball hitch itself is too low (trailer frame should be level), or the WD hitch load bars are not brought up high enough. Depending on what WD hitch you are using, you would either bring the load bar up to the next highest link in the chain, or bring the adjustment bars up. After adjustment, remeasure your front/rear hub-to-fender.
• If the front is dropping significantly more than the rear, the opposite of above is true. Either the ball is too high, or the load bars are too high (overloaded).
  
• Ensure your WD hitch is rated for your application. Given that you have a 900lb tongue weight, you would need a 10k WD hitch system.

Now with the above taken into consideration, you mentioned airbags. Airbags only help in bringing the ass of the truck back up when it's severely squatted. However, as I pointed out above, if your WD hitch is setup properly, the rear of the truck will be neither squatted nor raked. I personally don't believe in airbags used in tandem with a WD hitch as they oppose each other in terms of forces and create an even rougher felt ride. I would only suggest airbags with a Non-WD hitch towing load.

In terms of shocks (rancho's aside), shock valving can play a lot into the felt perception of the truck's ride. Factory shocks aren't great, but they aren't bad. They are more tuned for the majority of your day to day driving experience (and that would be NOT towing). Rancho's are going to be virtually identical feel unless your shocks are blown. Without diving down the shock valving rabbit hole, just know that you cannot have both at the same time You can purchase shocks that have some level of adjustability and revalve capabilities (bypass shocks or compression adjuster shocks), but be prepared to shell out some coin. A pair of my bypasses costs around $1300 bucks. At the end of the day, don't expect the truck to handle the same way loaded, as unloaded. Given everything you've stated, I'm inclined to think the WD hitch is not setup correctly and that is amplifying the felt problems inside the cab.

Hope this helps...happy towing.

 

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