Another factor is that, the closer you can couple the trailer and cab, the more aerodynamic the setup, and therefore the more fuel-efficient. However, I used to pull a step-frame supercube trailer that had the landing legs so far forwards that you had to put the fifth wheel all the way back on the tractor unit, leaving a huge gap between the cab and trailer, or the legs would hit the light clusters on the unit when cornering.
It is not just the run up ramps that suffer at the back end. One of my customers has had a variety of pin positions on trailers over the last five years. One in particular has a very short pin. This has more than once attempted to clean off the air and electrical lines from where they emerge from the rubbing plate under the trailer, when the now bent lead up ramp swings around.
Perhaps one of the more important aspects to remember is to reset the slider to the rearmost position before uncoupling from a deep pin if the next trailer is known to be shallow.
martinviking:
Conor:
martinviking:
If you think about it, with the 5th wheel set forward the trailer pivots at a different point, so if you’re on uneven ground & turning it has the potential to catch the chassis & wipe out run up ramps, mud guards & even lights if it’s too steep.
Wasn’t doubting you that it could happen, I’d just have thought you’d have felt some massive “there seems to be a problem I wonder what it is, I’d better go have a look” resistance as you were driving backwards.
Conor:
martinviking:
Conor:
martinviking:
If you think about it, with the 5th wheel set forward the trailer pivots at a different point, so if you’re on uneven ground & turning it has the potential to catch the chassis & wipe out run up ramps, mud guards & even lights if it’s too steep.Wasn’t doubting you that it could happen, I’d just have thought you’d have felt some massive “there seems to be a problem I wonder what it is, I’d better go have a look” resistance as you were driving backwards.
If you’re heavy reversing down a ramp you’re not going to be on the gas the run-up ramp would probably give way before it stopped the outfit rolling. They get crushed between the chassis and the trailer rubbing plate. On flimsier spec trailer rubbing plates you can sometimes see dents from going over humpback bridges back near the pin - if they run all the way back from the lip it’s more likely from an idiot picking up a loaded trailer without dropping the suspension.
The only time I’ve ever regularly had to slide the fifth wheel was when delivering trailers so there was lots of variety other than that just the occasional hire trailer with a different pin location.
As has been said close coupled is better for fuel consumption so there’s little choice but that option but I’ve always found it a more pleasant experience, both forwards and backwards, with the pin a bit nearer the drive axle.
A deep pin means its set a long way back so the front of the trailer is closer to the cab. There seems to be a little confusion over that above.
Best way to move a 5th wheel, as some other posters mentioned, is coupled to a trailer with the trl brake on.
Best thing to do with damaged run up ramps is take 'em off & leave 'em off. That’ll teach drivers to couple & uncouple in the correct manner!
Conor:
martinviking:
Conor:
martinviking:
If you think about it, with the 5th wheel set forward the trailer pivots at a different point, so if you’re on uneven ground & turning it has the potential to catch the chassis & wipe out run up ramps, mud guards & even lights if it’s too steep.Wasn’t doubting you that it could happen, I’d just have thought you’d have felt some massive “there seems to be a problem I wonder what it is, I’d better go have a look” resistance as you were driving backwards.
Luckily it didn’t happen to me & yes I hope that I would have felt it & jumped out for a look, I always open the windows when reversing & listen for any funny noises. I understand that its happened 3 times at Luppriens in Bletchley, on the ramp, 3 different drivers, 2 being fairly new & the last one being experienced, but the best one was at another company with a downward ramp, agency driver got it completely tangled with the trailer one night, apparently took 'em a couple of hours to get it untangled with everybody stood around offering advice [emoji1]
Be careful out there Guys & Gals, remember-
“If it ain’t Flat
Wear your Thinking Hat”
Driveroneuk:
A deep pin means its set a long way back so the front of the trailer is closer to the cab. There seems to be a little confusion over that above.Best way to move a 5th wheel, as some other posters mentioned, is coupled to a trailer with the trl brake on.
Best thing to do with damaged run up ramps is take 'em off & leave 'em off. That’ll teach drivers to couple & uncouple in the correct manner!
Best way to move the 5th wheel is as above but also drop the legs and dump the air taking any weight off the 5th wheel.
Have only had to move 5th wheel at one company - Walkers Crisps.
At the time, their DAF’s had moveable 5th wheel, controlled from inside the cab (on air). Their rules where, you had to fully extend the 5th wheel before you hook on, then connect up the leads - basically split coupling with the trailer attached - this gives you plenty of room on the catwalk. Once you’d done you’re checks etc and where happy, you’d then release the 5th wheel and back up as far as it would go, so the gap was closed off then resecure the 5th wheel - all 5th wheel movement done from inside the cab.
Uncouple, do the reverse.
A lot of bulkers have sliding 5th wheel, as the trailers need to sit further back if you have the hydraulic tanks in the back of the cab.
Mine is shoved all the way back as its the only way I can run with a chipliner. Can’t turn tight with it any other way. Maybe a notch forward but it took two of us the best part of an hour to shift the thing so its staying where it is!
A.
On a practical note, firms like Tesco don’t let drivers do “split coupling”.
When one couples up to a fridge trailer normally, there is often so little gap between front of bulging forward fridge unit and rear of tractor - that one needs to have a gap just to get up upon the catwalk.
The sliding 5th wheel in this case - gets around the otherwise need to split-couple. It is safer imo.
IF you had a tractor with the 5th wheel ratcheted back to full extension on a regular basis…
The issue then would be pulling your airlines when spinning around in the yard! - That extra extension and gap behind the cab is just that little bit too much for the standard suzies alas. 