[slowmover]

Okay let's look at the numbers. What is needed is the FF and the RR GAWR, plus the GCVWR from Toyota (owners manual, door jamb sticker).

First, the trailer

The VISA 19RSD has a dry weight (with zero options, no water, no propane, etc) of 2,832-lbs. It has a CCC of 1,028-lbs for a GVWR of 3,860-lbs.

As the standard 10-15% TW recommendation for American spec trailers is reflected in the TOYOTA 3,500-lb rating, that means they expect a TW of no greater than 525-lbs.

In a recent quote from an engineer (one of a number who like to do this problem solving), "Our members who have reported TV and TT weights, on average, load their TTs to about 85% of the GVWR. And a typical range of values for tongue weight percentage is 12-14%.

85% of GVWR for this trailer is: 3,260-lbs
14% TW is 460-lbs

All looks good, right?

Well, the empty weight of a .32 cd Sienna (stripper, no options, no driver, no fuel) is 4,275-lbs (same as my 1971 big block V8 Chrysler, ha!); and at a rule of thumb for driver, full fuel and options we can add 450-lbs:

4,725-lbs

With wife and two children plus a bit of junk, we can take that, conservatively, to

5,125-lbs.

GVWR is 5,995-lbs
CCC is now at 870-lbs (as distinct from original 1390)

We have added 850-lbs to the van as equipped and loaded. Thus, our Maximum Trailer Weight comes down to 2,650-lbs and the MTW is down to 397-lbs.

The standard answer, the standard analysis is that your trailer is likely a bit much for the van. The loaded-for-camping weight needs to be carefully checked.

The standard answer is that this is how it works on a pickup truck where the WD is 75% on the rear axle (or, about 345-lbs) and 25% to the TT axles (about 115-lbs).

Let's call it The Theory of Squat, the difference between the old and the new, as the "new" involves pickemups and the "old" involves cars.

On a truck the ideal is to have the Steer Axle retain the EXACT same height and weight both empty and hitched.

The way we used to set up WDH in the era pre-1980 when it was with cars we towed was known as the One-Third Rule:

Steer Axle: 1/3 of TW
Drive Axle: 1/3 of TW
Trailer Axles: 1/3 of TW

Or, roughly 2/3 to the car (303-lbs) and 1/3 to the trailer (156-lbs). The 2/3 on the car needs to be divided 50/50 FF/RR (151-lbs per axle), with a discrepancy of 10% or less, the bias preferred to the drive/rear axle.

This is more the way that Andrew Thomson looks to set up tow rigs. It works with low-payload vehicles (not trucks) as the TV re-distributes the weight more efficiently than the 75/25 bias of a truck.

This is roughly said I hope you understand. Thomson's understanding is deep.

You'll want to know the GAWR of each axle, and the empty and loaded weights represented by each from a certified scale. Weigh it with only the driver, full fuel and the stuff that never leaves the van. It will need to be weighed again, loaded for camping. Same for the trailer where empty is represented by full fresh water, propane, and stuff that always stays in trailer (hoses, tools, etc; but not food, etc).

The TW of the trailer is a separate weight that needs to be established.

You'll also want to find out how others are setting up the Sienna for towing (thus the recommendation of Thomson), and get it perfect for your combination.

This takes a stack of scale tickets to accommodate the range of hitch adjustments necessary (from a variety of loadings and trips; just stop off every time for the kids potty break and top off the fuel tank) until you can about guess at it.

Then, you will definitely achieve the best possible fuel mileage as you now have a balanced, well-handling rig where performance is maximized. Disc brakes will allow you to stop the rig faster than the van solo, with no brake fade.

.

.