Single or double axle for travel

Hi Tony

It depends in part on your travel plans and of course the size and weight of trailer/caravan.

Our previous van was a small single axled wind-up.

Advantage - could spin it round by hand if stuck in a tight spot.

Disadvantages; stuff was tossed from one side of the cupboards to the other (we travel off the bitumen frequently), damage to fittings, milk bottles and cartons leaking from the bottom from the bouncing. I wouldn't even try and take eggs!

My husband's reasoning in wanting duals had more to do with safety in case of a blowout or losing a wheel, and general stability of the unit. We have heard of nasty accidents with a blowout or loss of a wheel with single axled vans.

There is also less thrust up and down on your tow hitch with the van stable on four wheels.

We now have a smooth ride on four wheels (Simplicity Suspension) on our 18' van. I am well and truly convinced.

Motherhen

Hi Tony,
After having a tyre shredded on a single axle van before I knew it was flat I decided to go for the dual axle so that there would be more support for all the tyres should one go flat.

So far the theory has worked.

Running on more tyres also shares the load so that no one tyre is over taxed.

Dual axle vans are also more stable on the road in my opinion and less prone to tyre fatigue for that reason.

That is my preference for what it is worth.

Cheers Bruce.

Sanantone - Four wheels help spread the impact of rough roads and corrugations to the frame and chassis, if a load-sharing suspension is fitted.
The impact-spreading effect is lessened somewhat with a non-load-sharing suspension.
Four wheels are heavier to tow than two, so fuel consumption usually suffers a little.
Two axles are more stable than one, for most towing purposes.
Motherhen raised a good point about a blowout - but blowouts are fairly rare nowadays. However, they still do happen occasionally. You can damage a tyre carcass with a hit on a gibber and it will quite often not blow out, until some time later.

I'd have to take an educated guess that caravans/trailers lose wheels, more often than they have blowouts. This is usually due to wheel bearing failure - and wheel bearing failure can usually be sheeted home to seal failure allowing dirt/dust into the inner bearing - or water (allowing rust to start) - and the failure is also coupled with a lack of bearing checks.

The loading per axle is important. Many single axle caravans/trailers run overloaded - on tyres, bearings, and hubs - thus creating a potential disaster waiting to happen.
It's rarer to be able to overload tandem axles - unless the axles and tyres were very lightly specced from the word go.

I would only use a single axle on a camper trailer or a very small van. On a van over 4.2M, and travelling on outback roads, you'd be better advised to go with a tandem.

Hi Tony,
Let me recount an event that happened to me about 3-4 weeks ago.
I had travelled the Birdsville track, the Strzelecki track to Innamincka and on to The Dig Tree.
I left the Dig Tree and "drove" the 14k out to the hwy. While I was parked waiting for friends to catch up [two of us had left 1/2 hour before] a friend happened to walk around my 5'er and said "you have a problem". I did indeed, I only had three wheels, somewhere along the 14k a bearing had collapsed and the wheel and drum had parted company with the 5'er. 40 people could not find the wheel.
So I drove 350k to Thargomindah on 3 wheels and had repairs done. [still no spare].
I then was headed for Newcastle for repairs as I had bent an axle, 30k out of Bollon I blew a tyre [caused by running with a bent axle] so had to drive 80k to St. George for a tyre repair.
Had it been a single axle it would have been an all up lift to repairers.

PeterH

All good replies.
But consider the size of the van and your intended use.
A Kimberly Kamper for example, built to take on the off road tracks and tight turns will be ruined with a double axle. (just an example)

We have an Elite Goulburn 17' offroad van with control rider suspension with single wheels each side, no problem. Have done over 40,000 kms including about 3,000 kms of non bitumen.
Have done the GRR, Oonadatta track, roads up near Lawn hill and many more.
Loaded weight about < 2.3 tonne. Tows very well, no sway at all.
About to sell it and update with a new one.

Consider one thing.....almost without exception suspension systems and running gear on trailers are cheap and nasty in comparrision to that you would find on motor cars, light commercials or trucks.

This accounts for a great many failures and a lot of the decisions made and configurations we see.

All too often the trailers ( all types) will be running on wheels, tyres and bearings that are running very close to maximum capacity....the manufacturers and the buyers simply don't want to spend the extra $$$ to build a decent safety margin into their wheels bearings, axles, wheels and tyres....no matter how expensive the trailer.

All too often the suspensions are cheap and crude, in comparision to the tow vehicle.

If leaf springs are used are short, stiff and pretty poor quality......thus they ride poorly.

Mostly there are no shock absorbers, and if there are they have been fitted as an after thaught, mounted in an inefficient manner and not enginereed to match the springs or the load carried.

Then there are the independent suspensions.....some of them horrify me, the worst are as crude as the worst leaf spring systems fabbed up by some muppet with a welder possibly in a third world country.
The best may be fair but no where near the standard found in even the simplest motor vehicles.

Sorry to be a pesimist......but the quality of the suspenion system and its adequacy to do the job is more important than the number of wheels.

That said

Biigger wheels and tyres will always ride better and carry more load.

Longer springs will always ride smoother.....good luck finding a trailer with long springs.

Properly selected shock absorbers, properly fitted make a big difference.

Good quality wheels and tyres, correctly inflated and run well within their limits rarely fail.

Good quality, properly maintained bearings run well under their capacity rarely fail.

a single axle trailer will be a little easier to reverse and manover....less prone to scrub and crab.

A two or three axle trailer will ride over bumps far better

a rig with 2 wheels will generally be lighter than one with 4 or 6.

If buying an trailer with independent suspension....ask, where do I get spare parts.

There are some fairly good generally available independedent systems, that have good parts availablity......there are also those that are exclusive to a particular trailer company.

How is the support from that trailer company, and what happens if the company goes bust or changes the suspension they use.

A bloke I knew got into all sorts of strife when he could not get spares for a broken independent suspenion system.....he ended up replacing the whole suspension system to get his van back on the road......in a 12 month old van.

Unfortunately suspension systems on trailers are like politicians....you are selecting the best from a bad bunch and very rarely are they properly up to doing the whole job.

cheers