An obvious possible requirement would be some form of capable turning front wheels (maybe like a shopping cart?) But outside of that, overall braking ability I wouldnt see as being much if any affect. But I would see the likelyhood of increased towing capability for smaller vehicles, only needing to pull a weight rather than pull and lift/balance.
It doesnt even just seem to be a preference thing, because what I am picturing I’ve quite literally never seen, and I’m wondering if there is a simple answer or safety issue for why they dont exist.
I’ve done quite a bit of searching, but all results are just specs of existing products mostly, but never explaining why the standard setup is what it is today.
Any input is appreciated, and thanks for reading the long post
In: Engineering
Commuter trailers are center balanced because it’s easier to back them up and manufacture them. The multiple trailers found behind big rig trucks do indeed have fore and aft wheels, with the front wheels being attached by a “fifth wheel” plate. This means that the trailer has an additional axis that it can rotate around, which makes it very difficult to back up; it’s like pushing a chain.
If you’ve ever been at an airport and seen the little baggage tug, or watched a train going down the line you’ve seen 4 wheel trailers in action. There are downsides when it comes to these.
* A 4 wheel trailer needs to be able to at least turn its front wheels, otherwise the front tires will scrub across the road surface when the tow vehicle turns, totally killing the longevity of your tires. You might be able to get away with this on slippery surfaces like grass, ice, gravel, or dirt, but pavement is too grippy.
* The easiest way to make the front wheels turn is to tie them to the tongue, otherwise your dealing with hydraulics, cables, servos, or other complicated components. But that means if you have front wheels that turn, it means you no longer have a rigid connection to your load. So when you need to back up, it’s like pushing a rope, and you will have *extreme* difficulty making the trailer go straight, if it can be done at all you are either a master driver or have computer assistance. And you’ll have to think about the need to reverse every single place you tow your trailer.
Ever watch a ramp worker have to back up the baggage carts? They have to uncouple each of them and push each one back individually. Trains have it easy, as the axles want to stay on the rails whether going backwards or forwards.
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