Interesting Observations (at least to me)

[mtnguy]

In dewinterizing and sanitizing my fresh water system this spring, I weighed the tongue with various tanks full or empty, to see how weight was transferred around the camper.

My driveway has a slight slope, probably less than 1%. With my camper in it's usual storage spot and parallel to the driveway (tongue low), I filled the fresh water tank with bleach solution, and took a reading. Next, I took a short road trip to mix the solution well, and also splash the solution on the top of the tank. I pull back into the driveway truck 1st, now leaving the camper tongue high when parallel with the ground. This weight shift from tongue low to tongue high took 40 lbs. off of my trailer tongue !!! I never would have expected that much weight shift with that little tilt difference.

A possible variable: My Sherline scale does not seem to settle down exactly the same each time I use it with the same setup, but I think it is accurate within 10 lbs.

The next observation was raising or lowering the tongue. I have always heard that is best to travel with tongue slightly down if you can't get a trailer exactly level, to get the tongue to weigh more (theory confirmed by above observations). But I have always surmised that on a double axle trailer that may not be true, since you are changing the balance point between axles. As I raised the trailer tongue, the weight increased on my scale. Even though I was moving the center of gravity of the trailer to the rear, more weight was being exerted on the rear trailer axle, and taken off of the front trailer axle, moving the imaginary balancing point between the 2 axles with a completely level trailer towards the rear.

The tongue on a single axle trailer would still probably weigh more in a tongue down attitude, since there is a stationary balancing point.

Hope this isn't information overload.

[acadianbob]

It would also be interesting to know how much your tongue weight changes with fresh water empty versus full, etc. . . . .

[mtnguy]

Originally Posted by acadianbob

It would also be interesting to know how much your tongue weight changes with fresh water empty versus full, etc. . . . .

My fresh water tank sits over and behind my rear axle, the gray water tank sits directly in front of my front axle, and the black water sits directly in front of that. My water heater sits in the extreme back corner of the camper.

So here are the gains and loses with my trailer tongue weight:

Water added to fresh water tank (30 gals.): -20 lbs.
Water added to water heater (6 gals): -20 lbs.
Fill gray tank (30 gals.): +40 lbs.
Fill black tank (30 gals) : +80 lbs.

People say that I am anal.

[fordmantpw]

Very interesting information. Thanks for sharing!

[acadianbob]

That IS interesting!! Each trailer model will undoubtedly be different in the effect. On my SV235, everything is in front of the axles, sometimes WAY in front so I bet I'd get much heavier tongue weights.

[TheSasks]

Good info Chap..

[Bilcin]

My Black water tank sits in the very rear of the trailer, gray water next to the black and between my double trailer axles is the fresh water tank. Mtnguy, I think you said that you have at times used the water tanks to balance or affect the trailer tounge weight. Does anyone think adding a few hundred pounds to the weight of a trailer grossly effects fuel milage. Say 300 lbs of water to take some weight off of the tounge weight?

[mtnguy]

Originally Posted by Bilcin

My Black water tank sits in the very rear of the trailer, gray water next to the black and between my double trailer axles is the fresh water tank. Mtnguy, I think you said that you have at times used the water tanks to balance or affect the trailer tounge weight. Does anyone think adding a few hundred pounds to the weight of a trailer grossly effects fuel milage. Say 300 lbs of water to take some weight off of the tounge weight?

I don't use the water tanks to intentionally balance my trailer. I travel with about 1/4 tank of water if I am headed to a campground with hookups, and a full tank of fresh water if I am headed to a dry camping area. I always avoid towing with anything in my waste tanks.....other than a couple of gallons in the black tank so I don't have to deal with a "brown mound".

Bill, I can't remember the exact weights you had posted in your weight thread, but I will use these figures as an example. A 6000 lb. trailer with a 800 lb. tongue weight has a 13.3% ratio on the tongue. Using my water heater as an example since it it located at the rear of my camper and calculating from there, traveling with 30 gals. in your black tank will take ~100 lbs. off of your tongue. So now, you have a 6250 lb. trailer (added liquid) and a 700 lb. tongue weight, with a 11.2% tongue ratio. That is still over the recommended 10% minimum tongue weight, but under the "ideal" 12% weight. Plus you are going to have that black water sloshing around, which is going to contribute to your sway some.

Any extra weight is going to affect fuel mileage, but maybe not noticeable.

I don't' think traveling with full waste tanks are a good idea. What do you eventually do with that waste ??

Bill, did you ever do a follow up weigh-in with a competent scale operator ?? I am catching up posts, and didn't notice if you had or not.

[Bilcin]

Mtnguy,

Did not reweigh the trailer/TV yet, looking at a recycling company who has a single scale, I hesitate to go back to the Cat Scales that is close to me. I think they are only trained in weighing Tractor Trailer rigs only, as they were confused with the different weights I needed. When I find a different scale I will post them for comparison. Thanks for the reply.

Bill

[mtnguy]

Bill, you can get all the axle weights with a single scale......that is what I use. I think I posted how to do that on your other thread, but if you need instructions on how to do it and calculations, let me know either on the forum or via a PM.

As anal as I am, I even used another scale (stone center) to weigh my trailer axles side to side, as the quarry scale that I usually use has a side rails.