8 common caravan myths busted: Part 1
We burst the bubble on some of the most common caravan myths.
There is a lot of caravanning wisdom out there – some of it very useful and some of it not so much. So, to help keep you on the straight and narrow, our team of experts are here to separate fact from fiction, dispelling some of the most common caravanning myths and rumours...
1. YOU MUST HAVE 10 PER CENT TOWBALL MASS
This is one of the greatest pieces of misinformation that grew out of a legitimate rule of thumb in the 1970s. Back then, a caravan typically weighed no more than 1500kg and the corresponding 150kg was about right for a relatively lightweight vehicle towing it.
These days, caravans often weigh around 2000-3000kg and the mass on the towbar isn’t necessarily going to be 10 per cent. In fact, many caravans are now on about 6-7 per cent at Tare and, depending on how you load the van up, will stay at about that percentage on the ball.
Having towed many caravans with around 150kg on the towball – despite typically weighing 2000kg-2500kg – I have found their balance is perfect, with no hint of yawing.
2. YOU HAVE TO USE A WDH
A weight distribution hitch (WDH) is the great Band-Aid used by many caravanners in the mistaken belief that you’d be mad to ever tow without one. That’s not quite right, though. WDHs are not necessarily a must-have for heavy-duty caravan towing.
You need to measure how much the front of the tow vehicle rises when the caravan is hitched up. If the rise is more than 20mm, then you first need to reconsider how you balanced the payload in the vehicle and van. If rebalancing it doesn’t do the trick, then you have to consider using a WDH.
WDHs come with their own problems. In particular, the enormous loads they transfer through the vehicle’s towbar and frame. Even WDH manufacturers recognise this, stating quite clearly in their usage instructions to release the spring bars when negotiating driveways or spoon drains. This is the greatest downfall of the WDH, as many people don’t do this in practice. Instead, many users risk towbar and vehicle structural damage by keeping the WDH tensioned, as it’s too hard to stop all the time to release the spring bar tension and then re-tension it later.
3. AEROFOILS ARE JUST GIMMICKS
There are many fuel-saving contraptions on the market that are purely the invention of a feverish mind and not of any benefit for improved fuel consumption. However, the aerofoil, or aftermarket roof spoiler, is not one of them.
Having tested one over thousands of kilometres, I can attest to the improved performance and fuel economy when the spoiler was used compared to when it was not. The fuel consumption and performance benefits are more dramatic with some petrol-powered tugs than diesels (my XJ Cherokee saved 3L/100km on fuel and could be driven at half throttle instead of three-quarters throttle when using the aerofoil), but the benefits of using this device to flow air over a full-size van are clear.
4. DRIVING AS SLOW AS POSSIBLE SAVES FUEL
There is evidence to show that mechanical drag is surpassed by aerodynamic drag at about 80km/h, according to the boffins at Bosch. A tow tug’s gearing also has an influence, but cruising at 60km/h on your next tour won’t necessarily save you any more fuel than if you were to travel at 80-90km/h.
That’s aside from the massive conga line of traffic you’ll likely have behind you, many of the drivers fuming because they, unlike you, are not on holiday with all the time in the world. Drive to the conditions and you’ll likely still save as much at the bowser. And you’ll keep other motorists happy!
5. TYRES THAT HAVE LEGAL TREAD DEPTH ARE FINE
It’s the greatest mistake any caravan-newbie will make, and sometimes to their detriment. When you use a vehicle regularly, you replace tyres frequently because their tread wears out. So it’s understandable to think if the van’s tyres have plenty of tread left, they should be fine. Wrong.
Most vans don’t do many kilometres and spend a long time parked up at home until the next tour. But rubber degrades and once a tyre reaches five years from the date of its manufacture, it is living on borrowed time. It will eventually delaminate and blow out – usually in a spectacular fashion – possibly creating a danger for you and other road users. Keep tyres fresh by replacing them at five-year intervals and store them covered from sunlight and preferably off the ground, when the van’s not in use.
6. BEARINGS ONLY NEED TO BE CHECKED ONCE A YEAR
This is the theory for a van that has fresh bearings properly tightened and on a van that is used on good roads. The problem is that not all bearings are created equal (always buy the best quality bearings you can) and what seemed like a good tension when they were fitted might not be so good after a few thousand kilometres on rough roads.
Brushing your hand over the wheel face or bearing cap when at a rest stop on tour is a good idea. If it’s too hot to touch, you most likely have a bearing or brake problem.
I also jack up the wheels before every trip and check for bearing play; if the wheel feels even slightly loose, it’s time to properly investigate the bearing condition and play.
7. YOU NEED A SET PRESSURE IN THE TYRES
Nothing gets a bunch of opinions as much as tyre pressures do. Tyre pressures should be checked daily on tour, and the way to do this is to use the 5-6psi-rule for LT tyres and 4psi-rule for passenger tyres. That is, you should see a rise in pressures from cold to hot (hot meaning after around 50km of highway driving) by 4psi for P-rated tyres and 5-6psi for LT tyres.
If you have more than that, your starting pressure is too low, and if you have less, the starting pressure is too high. This isn’t something just made up on an internet forum; it is the advice given by tyre engineers.
8. MOVING AN AXLE UNDER LEAF SPRINGS IS THE BEST WAY TO INCREASE CLEARANCE
This one is so simple, so good in theory, but there is the potential for it to go horribly wrong. An under-slung axle secured by four U-bolt clamps may last forever, but if they do happen to come loose, the result is generally a wheel set and axle departing south from the caravan and rolling down the road in time for a hapless motorist to hit them. The best way to get more ground clearance is to flip the axle and keep it retained by the leaf spring sets.
The full feature appeared in Caravan World #547 January 2015. Subscribe today for the latest caravan reviews and news every month!