As an agency driver I go to plenty of different companies, with plenty of different Units and trailers,
sometimes the gap between the cab and the trailer is huge and I feel like I should be moving the 5th Wheel.
But I am unsure of how close I should get it, worried about damaging the cab or trailer legs hitting the lights/mudguards on corners, so I just leave it as it is. Like yesterday I had a single-axle city trailer and the gap between cab and trailer was about 1.5 meters.
Is this something I should be doing or should I not bother ? and if I should do it, how should I get the correct gap. Thankyou
i wouldnt bother mate id just leave it exactly as you find it the only time ive ever had a problem was garriby hill in the wet and due to distance between cab and trailer couldnt get traction but as i say in my opinion leave well alone and chances are even if you tried to move it you couldnt pull the handle out due to lack of use
Last week did a drop in Plymouth with 6x2 which was tight reverse and drop off the road, the fifth wheel was right back os the nose of the trailer dipped enough to catch the mudguards on the second axle. Lifting the suspension doesnt change the level of the mudguards.
Back in the yard had a look identical unit that had wheel about 8 ins further forward and not a mark on the mud guards, so got bar and sledge hammer and gently slid the well greased plate forward to the same position. I’m told that the clay company had problems with it being forward and grounding on the chassis on steep ramps.
So I now look if there’s combination of steep drop or rise combined with hard turn.
Normal running I doubt it matters but I’m sure there are some experts on axle weight distribution on the tractor
if you want to move it the best way is - back under trailer so the pin locks and fasten the dog clip, adjust the susension so there is tiny gap between the 5th wheel and the bottom of the trailer, pulled slider handle, driver truck to achieve the desired position, knock the slider handle back, drive the truck either way the small distance required for the pins to drop in, put the dog clip back in the slider handle, check cab / legs clearence, if ok couple up as normal!
We use ours to transfer weight to the steer axle from the drives. each notch moves about 100kgs forwards or backwards. Ours are on air switches so it is cushy. When you do move them, be careful about weight transferrance, and move it back if you are unsure.
or get a piece of scaffold tube about 3 feet long and sledge hammer from opp side to handle and disengage pins (if not as often greased as stevieboy’s wagon), same to bang it forward, (safer than using the trailer if it’s solid and suddenly lets go and arrives at the back of the cab) then bang the handle back in, might need some delicate adjustment forward or back to get pins to engage…may as well grease it at the same time in case anyone wants to move it again in the next two years.
As Bob the dog says it was noticeable just looking at the front tyres the difference it makes to weight transfer, hence comment above about slider position for traction.
stevieboy308:
if you want to move it the best way is - back under trailer so the pin locks and fasten the dog clip, adjust the susension so there is tiny gap between the 5th wheel and the bottom of the trailer, pulled slider handle, driver truck to achieve the desired position, knock the slider handle back, drive the truck either way the small distance required for the pins to drop in, put the dog clip back in the slider handle, check cab / legs clearence, if ok couple up as normal!
Well said stevieboy 308 thats the easiest way.the only thing you missed out was to leave the legs wound down thats how you get the gap
between the 5th wheel and rubbing plate… I know its common sense but if people have to ask in the first place they might wind the legs
up. also if you have someone to say how much the slider has moved. You don’t want the trailer headboard crashing in the cab.
John
move your 5th wheel to where your happy with it,get under your trl,put your elbow on your light cluster dont matter what side, extend your arm and make a fist, if you can swing your arm from left to right i.e 9 o clock to 3 o clock,and your fist dosn’t hit anything your good to go.if you touch anything your 5th wheel is in the wrong place.
p.s any one who has done traction will confirm the above.
Lycanthrope:
I know how to move the 5th wheel its how do I know the correct gap so I don’t cause damage thats my issue
Hiya …if its a case of been legal. you’ll have to look at the makers spec sheet i think years ago (my driving days) with a 114 inch
wheelbase 2 axel unit the pin should be 18 inches infront of the centre of the axel. so its not the gap behind the cab its centre
of 5th wheel to centre of axel.it gets complecated now with three axel units pulling a tandam trailer with the wheels to the back of the trailer or if your pulling a triaxel. Its typical drivers problem knowone will tell you propley its when you get stopped by VOSA they will say
thats wrong lad.
John
As a guide I use my forearm as a rule. front of trailer to back of cab = about 16" and the same from legs to rear lights.
I know this isn’t exact but a reasonable guide.
at Argos MP all the trucks have easilly moveable 5th wheels
cos your encourage to run with trailers as close as needs be
saves fuel …you get shown this ion your assesment
having now got a proper job …i missed the latest catalogue launch yippee
I remember when Celsius First had the new Volvo Globetrotters in at Hams Hall, first day of using said new truck, a driver tried to move slider closer to cab, unfamiliar with new fangled I-shift and bang, big dent in rear cab of brand new truck which couldn’t be fixed and stayed like that for years. O the walk of shame…
They had them stupid suzies which come out on a boom from under the trailer as well so within a few months the cabs were black with grease anyway. Never seen new trucks get skanked so quickly.
Thankyou
slid the well greased plate forward to the same position. I’m told that the clay company had problems with it being forward and grounding on the chassis on steep ramps.
or get a piece of scaffold tube about 3 feet long and sledge hammer from opp side to handle and disengage pins (if not as often greased as stevieboy’s wagon), same to bang it forward, (safer than using the trailer if it’s solid and suddenly lets go and arrives at the back of the cab) then bang the handle back in, might need some delicate adjustment forward or back to get pins to engage…may as well grease it at the same time in case anyone wants to move it again in the next two years. 
its how do I know the correct gap so I don’t cause damage thats my issue 