Nose weight accuracy

[Ron_5041484]

For many years I used to test the weight with a peice of wood and a set of bathroom scales I recently purchased a dedicated telescopic nose weight scale I have a 90kg limit on my car but I find that the scales depress so much with that sort of weight that the van goes very out of level and seems to give me false readings can any one explain this to me (ie) does the nose weight increase the closer the tow hitch gets to

the floor . Ron .perplexed.

 

[Lutz]

If the noseweight scales that you bought have such a big range of travel that the attitude of the caravan changes noticeably when measuring the load, then I'm afraid to say they are very poorly designed and unfit for the purpose. Noseweight can increase dramatically as the tow hitch comes down. It should therefore always be checked with the coupling at its operational height, i.e. the same height as when car and caravan are hitched together and all respective payloads on board.

 

[ProfJohnL]

Hello Ron, The quick answer to your question is yes, the down force at the tow hitch does increase the lower it is to the floor. The correct nose weight will be obtained when the caravan is level. The more detailed reason for the weight increasing when the tow hitch dips, is that the caravans centre of gravity will be somwher above and slightly forward of the cravans main axle. when the towhitch drops, the caravan tips forward rotating about the axle, and so the centre of gravity will also rotate slightly more forward than previously. This increases the turning moment generated by the centre of gravity which results in a greater down ward force on the tow hitch. The converse is equally true, and if the hitch is rasied the down force will reduce. In some caravans if the hitch is rasied enough, the centre of gravity will rotate about the axle sufficently far to end up behind the axle, and this actually generates a lifting force at the towhitch allowing the caravan sit with its rear edge on the ground and the hitch in the air!

 

[WatsonJohnG]

My drive slopes down so the the front of the van is the highest point from the drive.I put my nose weight gauge on the trolley jack and jack up until the van is level to get a more accurate reading

 

[ProfJohnL]

In response to Brians query, Yes in theroy the the car and caravan should be level when hitched and loaded correctly, however with the exception of cars with self leveling suspension, I don't know of any car that can sustsian a tow hitch load without dipping. So to comply with the caravan manufactures maximum figure the caravan should be level, to comply with car manufactures to hitch limit the hitch must be loaded. The difference will only become a problem if both the car and the caravan are at, or close to their limits.