Ideas & Information

Our caravanning is very much on a budget, so if there is a cheap, simple but effective way of doing things let me know!

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The case for Weight distribution Hitches

 This was a topic I personally found quite confusing so here is my attempt at an explanation.

When you drop the caravan hitch onto the towball the back of the tow vehicle drops.  The instant thought is if you put heavy duty springs on the back wheels then you will restore the vehicle to level and all will be well, this is what I thought initially.  It may look fine but actually all is not well. 

If you consider the diagram, downward pressure (red arrow) on the drawbar means the vehicle will pivot around the back wheels (green arrow).

It follows then that the front of the vehicle (blue arrow) will come up because of the seesaw principle.

Ignore springs in this argument as they actually have no impact on the physics of the situation.

If the front has come up then weight has been removed from the steering, braking and traction.

Not a good idea as this means less control, especially when you need it in an emergency situation.

 A weight distribution hitch redistributes the weight to the front wheels, something that heavier springs cannot do.

Heavier springs deal with the extra weight inside the vehicle, they cannot redistribute weight to the front wheels.

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Tyre Pressures

The following is from the NRMA caravan info site:

We had quite a saga with everything in the van rattling around.  I did a bit of research on what was the optimum
tyre pressure for our small van and came across the "4psi rule". (scroll down to "Tyre pressures - do-it-yourself check")

Tyre pressures - do-it-yourself check

It is impossible to list the correct pressures for every caravan, due to variation in size, load, etc. This easy check will help you find the best pressure for your caravan tyres.

1:  First inflate the tyres to the pressure recommended by the manufacturer of the trailer or the tyre you are using. Secondly, tow your trailer for a distance of 100 km, preferably on a highway.

2:  Recheck the tyre pressures immediately after pulling over and compare them with the pressures you had at the start of your run. If the pressures are right, the hot readings should be 4 psi (28 kPa) higher than the cold readings.

3:  If there is a greater than 4psi (28 kPa) difference between these pressures, the tyre temperature is too high and the pressure needs to be increased. If there is less than 4 psi (28 kPa) difference, the pressure needs to be lowered.

4:  Large 4WD tyres will have a differential of 6 psi (42 kPa).

5:  Be sure to use the same accurate gauge for both readings.

Our optimum pressures ended up being about 5psi lower than specified.  I checked with the manufacturer and they confirmed that this was indeed correct for a light van.

 

Another Approach

Another way to find out approximately what pressure you should run is from a very simple formula derived from the tyre specifications:

max tyre pressure divided by max load rating times actual load per tyre

in my case (450Kpa / 950kg) x 450kg = 213kpa   (30psi)

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Towing with an Auto Transmission

There is always a lot of discussion as to whether you should tow in overdrive with an auto transmission, The following article is from

DRW Transmission Specialties, Inc and gives a good insight as to what happens when you labour an auto. 

A worthwhile read!

Trucks or Cars Towing with Automatic Overdrive Transmissions
    An interesting job came in this week that made me want to write this tip for those who tow with automatic overdrive transmissions. A year 2000 Ford F-350 Powerstroke diesel 4 X 4 truck with Ford's top of the line 4R100 transmission came in with a TCC slip code stored in the computer. This is usually an indication that the torque converter clutch has started to slip and in most instances only requires a torque converter change. The client indicated that after he had towed this one particular time, the transmission temperature has been rising higher than usual when climbing hills, whether towing or not. We were worried that a burned clutch pack may be helping to generate this added heat, so we pulled the trans down for inspection. The overdrive clutch pack was burned. Not completely, but well enough to ruin the friction coefficient (holding capacity) of the clutch pack. Looking into the unit further to try and find the cause for the failure turned up nothing. Next question, "Were you towing in overdrive?". The client answered yes. Problem solved. The following will describe why the overdrive clutch failed and what you should do to keep it from happening to you. Because the manufacturers are always trying to do what the consumer wants, many have put into the owner's manuals that it is OK to tow in overdrive with some particular models. That may be fine for most driving situations, but let me tell you when it's definitely not OK to tow in overdrive. Your towing a heavy load and you hit an uphill grade. It's steep enough to cause you to press on the accelerator quite a bit. Remember we're pulling a heavy load. The trans decides to drop out of OD and it allows you to gain some speed up the hill. You reach a situation when the trans shifts back into OD and this causes you to lose a little speed. When enough speed is lost the trans downshifts out of OD again, and back and forth it goes as you climb the hill. Some of the more mechanically inclined fellows reading this are saying to themselves, "I know what happened to that OD clutch pack!" For those that haven't figured it out yet, I will clarify. Every time a band or clutch pack in an automatic transmission applies or is turned on, heat is created. Add to the fact that you are towing, and the heat that is generated during an application of a friction element is even higher. The friction element needs time to cool after an application. If it hasn't cooled enough before the next time it is applied, the heat builds up to a level where the friction material starts to burn. Once the material is burned it is down hill from there. The trans will have to come out. What can be done to combat this? Number one, make sure you have adequate cooling capacity of the transmission fluid. Any towing will require that you install an auxiliary cooler for the transmission. Do not bypass the extremely efficient trans cooler that is already in the radiator. I also recommend installing a trans temperature gauge, especially if your towing heavy loads. Nothing beats knowing exactly what your trans temp is. The client that owns this particular truck was able to tell he had a problem by just watching his trans temperature and relating it to past temperature levels experienced. Smart guy. The other thing you can do to prevent this type of damage is to drop to the next lower gear if you experience shift cycling. If your in OD and the trans is shifting back and forth from 3rd to OD, drop the shifter into 3 to save wear and tear on the fiction elements involved. It's that simple.

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Tainted Water from Plastic Water Tanks

 Put about 20 litres of water in the tank with half a packet of bicarbonate of soda and go for a drive (eg. the first day of your trip).

Drain and refill with fresh water.  Works a treat!

Always make sure you are using fittings and hoses rated for drinking water otherwise nothing will improve the taste.

 Note:  All this assumes that drink safe hoses/connections are used and that they are black (i.e. no light can get into the system to allow algae to grow)

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Pop-top Support

I  have recently fitted side and rear awnings to the van, as a consequence the pop-top is somewhat heavier and is now sagging.  Short of fitting new scissor lifters it was suggested that I carry a couple of props to support the extra weight. 

What I have done is to get a few window locks from the local bargain shop.  When I have raised the roof to the correct height I just clip one on to the lower guide of the lifters against the roller and that holds the top up.

 

                                       

"The Wharehouse" Special                                 Actual Clamps         

I have hacksawed about 2mm off the back of them (see picture) and bevelled the edge of the thumbscrew.  This allows them to sit snugly down in the guide and saves damaging the galvanising of the guide.

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Contact details:  sdavo@yahoo.com
 

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