Can anyone tell me the advantages of having steering axles on a 45 ft tri axle trailer. And is there anywhere i can compare turning circles with a standard trailer etc …
Boss is looking at getting one so would like to check out the benefits
Thx
The most obvious saving would be in tyre wear, although this could be negated by higher maintenance costs in relation to the extra moving parts.
With a rear steering axle, all three axles tend to be positioned slightly further back on the trailer, and could affect the loading on the drive axle with a 4 x 2.
Turning circles should be comparable because Con & Use Regs require that the vehicle follow a path within two concentric circles of 12.5 metres and 5.3 metres. i.e. With the front of the Unit not going outside the larger circle, the trailer wheels must not enter the smaller circle. Hence this requirement limits the positioning of the axles on a non-steered trailer, but provides more flexibility with a steered rear axle.
Some people say that they follow better, but I’ve never noticed any difference.
All our trailers are reer steer, doing milk colletions from farms, the reer steer trailers arr the best thing since sliced bread, you would be amazed at some of the places you can put a 35t reer steer trailer, they do follow you much much better, you dont need to take such wide aproachs at some junctions or going round tight bends etc.
I wasnt sure when i first started to drive them, but i took to them like a duck to water !
Im not sure how all reer steer trailers work, ours turn on the fifth wheel, there is a plate on the trailer which sits on the fifth wheel when its coupled up, and when the unit is not in line with the trailer, the reer axle is turning to the same degree, and you cant lock them on ours ! Just make sure when you drop it, you drop it straight.
When I worked for Fullers transport a few years ago we had some rear stear tri axles fridges. The rear axle was floating and so just followed, made easy work of London, but you had to lock it to reverse otherwise the trailer would crab sideways, which made life interesting at times 
obvious advantages are tyre wear reduced, fuel economy increased, they actually turn more like a tandem (going forwards)
two types available i believe
simple drag type
then theres the store delivery (turntable) powered stear like tesco etc
powered version is excellent in tight/hard to manouvere situations
From the drivers point of view if you can drive the tractor unit through then the trailer will normally also follow.
the disadvantages are that when you come to reverse in a tight space & are unable to get the steering straight prior to the reverse, then it’s climb out & lock the rear wheels & when driving into a tight side road etc, the trailer can go a little wider than the tractor, so you need to be aware of that.
Going forwards they make life a lot easier, especially when driving on busy roundabouts, or city driving etc, where cars or pedestrians are moving around you as you are turning.
Great fun to reverse if they haven’t locked! 
Never driven a self steer but had a positive steer on brick and block for a while and couldn’t believe how easy it made the job - try it, you’ll like it!
Brilliant to reverse as lady say’s if not locked
About a year ago I had one of those silly little “City” trailers to collect & drop off, fridge not working I was told.
What they didn’t tell me however was steering would not locking either, I hate reversing these stupid little things at the best of times, they always seem to over steeeeeeeer on a 3 axle tractor unit.
Oh what fun I had.
Two ways to deal with a trailer where the steering axle fails to lock:-
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Dump ALL of the air out of the trailer suspension, OR,
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Carry a 1/2" bolt, go under the back of the trailer and drop it into the two holes that line up when the trailer is straight.
Just remember to remove the bolt afterwards.
I used to do a regular run from Felixstowe to Garforth (nr leeds)
I bought my rear steer during this contract and I saved 9 gallons of diesel on the round trip
400 miles round trip 44t up empty back.
daxi:
About a year ago I had one of those silly little “City” trailers to collect & drop off, fridge not working I was told.
What they didn’t tell me however was steering would not locking either, I hate reversing these stupid little things at the best of times, they always seem to over steeeeeeeer on a 3 axle tractor unit.
Oh what fun I had.
Have you ever seen the dutch guy parked outside the flower shop on the corner of dereham rd and heigham rd? Various axles and fith wheel at every angle known to man!