Thread: Do We Over-engineer Trailers?

In the last 25 or so years I have lost count of the all the under engineered trailers that I have fixed. Most of the problems have been snapped aframes, springs busted, spring hangers ripped out, spring hangers cracked off, axles bent/ broken and the list goes on. I am sure that these trailers are fine for taking the occasional load of rubbish to the dump or the occasional heavey load around the city, but for heavey everyday use they are not up to the task.

Do we over engineer our trailers, I don't think so.

My own trailer, (which I consider to be on the light side) that I built is made from 1.5 plate sides and floor with a 50 x 50 angle chassis, 25 x 25 x 3 crossmembers, 4 leaf springs with a 50 x 50 x 5 rhs axle and a 65 x 35 x 3 rhs aframe. It is 1850 long 1350 wide and 300 deep, I have many times had it loaded level with builders mix gravel and sand, and have drug it to Rockhampton, Maryborough and brisbane a number of times, never having less than 750kg in it has never had a problem.

Robert

A senior engineer I once worked with coined a phrase that has stuck in my mind ever since -

"Over engineered is a matter of conjecture; under engineered is a matter of fact"

I'm sure if you could tell him every single force and event that trailer would experience he could design you a trailer right on the edge of "it's good". As it is, any object that is designed has to be able to cope with both "most likely" as well as "it might".

Michael

I got a trailer made for me and while it does the job i can't help thinking every time i have a look at it it's under done, as far as the wall thickness in the box section goes ,it tows well i can cruise at a 100 without feeling it there but i have to keep an eye out in the rear vision mirror just to make sure it's still there ,if it doesn't crack up i'll be a happy chappy but if i'v got to reinforce it at a later date i'll know i was right about the dark thoughts i shoot at it at times.

I'd rather over engineered than 'just right'. Because as sure as eggs, I'll over load it.

Cheers,
Wahoon.

I'm a fan of over engineering.

You should see the cars I build!

But those KIWI's seem to tow some pretty lightweight style trailers and some are obviously a good age.

I know our roads are harder than theirs on things like suspension, which may explain why they get away with it, plus they don't get up to the speeds we do.

I'd rather over engineer & know it works than under engineered & hope it works.
In saying that, there's over engineering & then there's ridiculous

Originally Posted by specialist

In the last 25 or so years I have lost count of the all the under engineered trailers that I have fixed. Most of the problems have been snapped aframes, springs busted, spring hangers ripped out, spring hangers cracked off, axles bent/ broken and the list goes on. I am sure that these trailers are fine for taking the occasional load of rubbish to the dump or the occasional heavey load around the city, but for heavey everyday use they are not up to the task.

Do we over engineer our trailers, I don't think so.
Robert

Me too.
It is horrifying to consider that many of these monstrosities were towed to our respective workshops for repair, often via highways, through school zones and past pedestrians when at anytime there could have been a catastrophic failure.
I have seen far more UNDERENGINEERED trailers than overengineered.
Crappy drawdars, mild steel bolts through couplings, the list goes on. I have even seen cocky cage welds hidden under bog and a first class paint job.
I am not a fan of over regulation, but I do believe it is too easy to build and register a trailer in many cases, (a great many of the inspectors would not know what they were looking at anyway), lights work, safety chain stamped, form stamped - go away to get your sticker and plates.
We all know that trailers are regularly pushed past their plated limits, so there has top be an allowance for this at the design stage, plus a great many trailers are towed by people perhaps best confined to a wheel barrow.
If I want to drive a little tip truck that weighs 5.0 tonne, I must get a light rigid truck licence, (and remain at 0.0% BAC while driving it) but I can happily drive a 3.0 tonne four wheel drive with a 3.5 tonne trailer behind with no extra certification other than a current drivers licence at up to 0.05%BAC. Even with the best braking and hitch system, the fourby and trailer will be more of a handfull than the tip truck, yet many people seem to have the attitude that it is "just a trailer" and will opt for the lightest, cheapest, lowest they can every time.
Are trailers under engiineered? No I don't think so.
Should we require licence endorsements for trailers over a certain size range? Most probably yes, or at the very least impose the 0.0% BAC rule.
As a volunteer emergency worker, I have attended many accidents involving overloaded, poorly loaded, poorly built and maintained trailers towed by inexperienced drivers driving undersized vehicles. Many take the whole trailer concept too lightly.

Hi All,
....overloading a trailer is no accident. I had some students built an ultra light box trailer for going to the tip etc and it is a pleasure to move around the garden, 2 removable thick plywood gates, so I can fit a sheet of 2.4m plywood in, single leaf spring,1.7 gal sheet body and 40x40 thin wall SHS. As long as I DON'T OVERLOAD it's wonderful......I love my ultra Light It is the best trailer I have owned