Checking connection

[Buckman]

After we have heard the "clunk" and hitched up, we have always lowered the jockey wheel to raise the hitch and rear of the vehicle to test the connection. I know that the load should not exceed the parameters of the hitch i.e. 100kg, but if you are doing the opposite to raise the hitch and rear of the vehicle does this put an extra strain on the hitch as that may be outside its design parameters as that will definitely exceed the 100kg limit imposed on most hitches for caravans? What is your opinion?

 

[borderbilly]

I do same as you, raise the tow vehicle a little bit.

 

[RogerL]

The 100kg limit is a static limit, which takes into account that the dynamic forces on the move can be significantly higher - winding the jockey wheel down to test the connection will increase that static load but I doubt it would exceed the dynamic loads.

On a car with air suspension, don't be too aggressive in winding the jockey down as the car will try to keep the rear level by reducing the rear axle spring pressure, increasing the load on the towball.

 

[Buckman]

The 100kg limit is a static limit, which takes into account that the dynamic forces on the move can be significantly higher - winding the jockey wheel down to test the connection will increase that static load but I doubt it would exceed the dynamic loads.

On a car with air suspension, don't be too aggressive in winding the jockey down as the car will try to keep the rear level by reducing the rear axle spring pressure, increasing the load on the towball.

If you are lifting the rear of the car using the jockey wheel, surely the load would be zero?

 

[RogerL]

If you are lifting the rear of the car using the jockey wheel, surely the load would be zero?

I see what you're saying - the load on the hitch will be reduced.

 

[Buckman]

I see what you're saying - the load on the hitch will be reduced.

I would have thought that the load on the hitch would be increased due to downward force and the load on the towball reduced?

 

[Mr Plodd]

I would have thought that the load on the hitch would be increased due to downward force and the load on the towball reduced?

Loadings on both will reduce due to the jockey wheel taking some of it as its wound down. In theory, if tge wheel is wound down a lot both loadings will go to a minus figure.

My "Go to" confirmation is pushing the stabiliser hitch down. If its not connected correctly then the friction pads have nothing to resist their inward movement, so the lever will go down with minimal effort.

 

[ProfJohnL]

I would have thought that the load on the hitch would be increased due to downward force and the load on the towball reduced?

The load on the hitch will change and might even reverse if the activity is taken to extremes, if you really lifted the rear of the car to the point the rear tyres were free of the ground you will definitely exceed both the static and the dynamic load margin of the caravans hitch and jockeywheel which would probably have collapsed by then.

Using the jockey wheel within reasonable limits to check the hitch engagement is a in sensible activity, and shouldn't exceed or damage any of the mechanical components involved.

 

[Buckman]

I think you would need to be very silly to lift the rear wheels of the vehicle off the ground using the jockey wheel.

Contrary to another post, if lifting to check the connection, I would think that it is impossible for the load on the caravan hitch to reduce as "load" can be from any direction and I am no engineer. In this scenario the load would be lifting the towball on the car.

 

[Dustydog]

I’m another who has always slightly lifted the caravan to ensure the hitch is secure. I doubt the load exerted upwards on the hitch and towbar has ever exceeded 100kgs doing this.

 

[Banus]

Belt and braces check. Wind the jockey wheel and as soon as I see the rear of the car start to lift - thats enough, then I physically get on my hands and knees and look up at the ball located inside the hitch to check its position.
As Mr Plodd mentioned above if the connection is incorrect the friction pads will not need the usual force to engage on the ball.
All said and done, I'm still a bit nervous and watch my mirrors very carfully for the first 100m or so after pulling away. Can't be too careful.

 

[izzy]

I also raise the hitch to confirm connection,
never occurred to me about the friction pads though
You learn something new everyday

 

[Sam Vimes]

I just use my hands/arms to pullup on the hitch once connected. Then after a few kilometers if there's a pull in handy I'll just stop and check again.

 

[Buckman]

I just use my hands/arms to pullup on the hitch once connected. Then after a few kilometers if there's a pull in handy I'll just stop and check again.

How many hernias have you had?

 

[GaryB]

Along with winding the wheel down as the rest I just feel underneath and ensure that the pawl on the hitch is located correctly on the underside of the ball.

 

[Gafferbill]

......and another variation!

I pull the hitch lever up as in cocking a gun.
It retains this position until it is lowered onto the ball.
When correctly attached it will snap shut with a loud click.
Before raising the jockey wheel I do the wind down raising the car test.
(no worries in doing this test for me)
If all is well I then engage the stabilisation lever.
I then wind up the jockey wheel making sure it engages in the anti unwinding slot and the clamp is tight.
Finally I check the electrical connections and that the ATC has a green light.....a working ATC is a condition of my insurance.

 

[ProfJohnL]

..... I would think that it is impossible for the load on the caravan hitch to reduce as "load" can be from any direction and I am no engineer. In this scenario the load would be lifting the towball on the car.

If you use the jockey wheel (JW) to lift the A frame to check the hitch has properly engaged, then as soon as the JW begins to lift the A frame you are beginning to share the support of the A frame through the both the JW and the hitch.

The greater the lift you apply a greater proportion of the load will be taken by the JW, and correspondingly less load carried by the hitch as shown by the relaxing of the cars rear suspension.

As soon as you raise the A frame enough to allow the cars towball to rise to its unhitched ride height, the ball will no longer be adding any support to the hitch and the A frames entire load is supported by the JW alone

If continue to to raise the A frame beyond the cars unhitched ride height, you are lifting the car and the transfer of load from the cars rear suspension to the JW will rapidly increase the load on the hitch, though now the direction of that load is reversed an the ball is trying to be pulled out of the hitch.

 

[Sam Vimes]

How many hernias have you had?

The nose weight is only 70/80kgs and I can lift and support that amount for a while. In fact when the hitch can't be wound down low enough I'll hold the hitch up while Mrs V releases the jockey wheel clamp and pulls the post up.

Then she takes me to the local chiropractor. 😉

Always eat porridge before attempting the same.

 

[Buckman]

Then she takes me to the local chiropractor. 😉

Always eat porridge before attempting the same.

Should be eating your Weetabix and not porridge!

 

[borderbilly]

Should be eating your Weetabix and not porridge!

Weetabix is for southern softies, us real men ( Scottish) eat porridge 😋.

 

[Dustydog]

The nose weight is only 70/80kgs and I can lift and support that amount for a while. In fact when the hitch can't be wound down low enough I'll hold the hitch up while Mrs V releases the jockey wheel clamp and pulls the post up.

Then she takes me to the local chiropractor. 😉

Always eat porridge before attempting the same.

That ‘s Olympics ! 1.4 Cwt. You must be a very strong bloke Sam. Impressive🤪

 

[Sam Vimes]

It's not as grand as it sounds. You don't have to lift the full nose weight on hitch when it's attached to the car as the car suspension helps with the lift.

For supporting the hitch to adjust the jockey wheel post you just have to support it for a while and your legs do most of the work.

 

[RogerL]

The nose weight is only 70/80kgs and I can lift and support that amount for a while. In fact when the hitch can't be wound down low enough I'll hold the hitch up while Mrs V releases the jockey wheel clamp and pulls the post up.

Then she takes me to the local chiropractor. 😉

Always eat porridge before attempting the same.

Shouldn't you be in Paris for the weightlifting?

I could only lift about 50 kg in my younger days - useful when caravans in those days only had a noseweight of bout 50kg - nowadays I struggle with anything over 20kg.

 

[Dustydog]

It's not as grand as it sounds. You don't have to lift the full nose weight on hitch when it's attached to the car as the car suspension helps with the lift.

For supporting the hitch to adjust the jockey wheel post you just have to support it for a while and your legs do most of the work.

Sam
Forgive me but have you changed your surname or am I having an optical illusion blonde moment🤔

 

[Sam Vimes]

Sam
Forgive me but have you changed your surname or am I having an optical illusion blonde moment🤔

Erm.... don't quite get that one.

Unless you've worked out that Sam Vimes is an anagram of Clark Kent.