Small towable cement mixers, the six to twelve cubic foot models, generally don’t have any way to adjust the tongue weight they put on a vehicle. This is just fine because unless you have a hitch that’s three feet off the ground, the manufacturers have put the axle in the most optimal location for towing. Additionally, the units weigh next to nothing and add little weight to the towing vehicle.
The larger models of cement mixers, such as the mixing trailers made by Cart-Away, Trailer Haul (no longer produced), Ernest, etc, all have much larger capacities, and therefore, much higher weight. The GVW of the average one cubic yard concrete trailer is 7,000 pounds. Cart-Away even has one model, the MixKing Concrete Mixing Trailer, that has a 10,000 GVW.
Accordingly, these cement mixers place a lot more weight on the tongue of the towing vehicle. In a perfect world, this tongue weight wouldn’t make any difference at all. Then again, this world is far from perfect: hitch heights and styles vary depending on the make of the towing vehicle, the model, the tire size, the bumper make, etc. Since a manufacturer can’t make a mixer trailer for every variable in the automotive world a different solution had to be found.
That solution was found in 1975 by a guy named Neal Surry. Surry was an engineer with the pioneers of the trailered concrete industry, Sunrise Systems. Neal designed what has evolved into the Vari-height Tongue that all of the cement mixer trailer manufacturers use now. The vari-height allows for nearly every hitch height scenario and can vary tongue weight on the towing vehicle with a simple turn of a hand crank.
So, how much tongue weight is the correct amount? That will vary from trailer to trailer. However, a good rule of thumb for a double axle trailer is to use the vari-height tongue adjustment to get the fenders level. This will distribute the weight evenly onto both axles of your cement trailer.
Cart-Away Concrete Systems is the world leader in concrete mixer trailers and uses the vari-height tongue adjustment on every trailer that they produce. There is a YouTube video on the mixer trailer that will demonstrate the use of the tongue adjuster on these cement mixers.