Was following a rigid this morning for a while on the M4 one of those with a big body but smallish wheels like the type used for carrying large quantities of light stuff, anyway it was crabbing like a good un and it stood out like a sore thumb. Surely this would be stopped by vosa or old bill but I was wondering what would cause it to crab like this, a smash maybe 
Iâd agree a smash maybe the cause.
Or a bad repaor after the smash.
Rear steer in need of adjustment?
Crabbing?? Like its driving sideways?? If so I have noticed this on a few motors before and always thought they must have had a smash to be like that, some you see are really bad.
schrodingers cat:
Rear steer in need of adjustment?
No it wasnât rear steer just a normal four legger on a 51 plate.
Hiya weâd need more info to the vehicleâŚif the truck had springs on the back axle the main leaf could have broke letting one side of the axle to slip back by only 25 mm would cause crabbing.
the centre bolt that goes through the spring and locates on the axel could have moved
(loose u bolts) and let the axel move back on one side⌠some one may have fitted the
wrong sping (longer distance from the centre bolt to the spring eye.) moving the axle back
on one side. this happened to me years agoâŚ
a really bad situation the chassis could have broken so all the backend has gone back
on one side(this has been a problem with MAN 8 leggers )see south wales site 4 days ago.
these problems could also happen on the front axelâŚyou need to know more about trucks
to say the exact problem Iâve just tried to help you a little.
I suppose you should know some of the above to fill in a defect book incase you come across
the same problem on your daily inspection.plese note this problem is bad news and the truck
shouldânt be driven or a proabition order could put the truck off the road as too dangerious.
Good luck
John
^ what he said ^
Must be interesting taking a crabbing truck down a narrow lane or street 
bald bloke:
I was wondering what would cause it to crab like this, a smash maybe
Did you get a look at the driverâs face?
Sometimes the body can be out of line (broken securing bolts), the chassis is straight but gives the optical illusion of driving sideways.
When reversing a vehicle thats âcrabbingâ, it can be a painâŚnot so much now with modern trailers but the old 40fts could be a pain in the â â â â .
We had one like this in our yard, our old TM (good riddance) had to be shown with tape measure before heâd do something about it. iirc the o/s wheelbase was 50mm longer than n/s.
SmashedCrabFace:
bald bloke:
I was wondering what would cause it to crab like this, a smash maybeDid you get a look at the driverâs face?
Were you on the M4 this morning near Bridgend ? If so it was you then
SmashedCrabFace:
bald bloke:
I was wondering what would cause it to crab like this, a smash maybeDid you get a look at the driverâs face?
I once followed a similar vehicle along a bendy road, every time he went round a bend it changed over as to which side it was crabbing to - and badly at that. If the driver didnât realise he wasnât fit to be driving.
Tâwas in the days before moblie phones, when I got home I phoned the bakery concerned and asked for the TM. It seemed he didnât like being told about it, so I said âok, next time I see a problem with one of yours Iâll just phone VOSA (or whatever they were called in those days) instead,â and hung up.
Loose U bolts for sure. That loose in less than 6 weeksâ â ?
Done a service van job on a unit with a â â â â -eyed back axle. Tyre fitter had jacked it up by the link arms, bent the arm right up, pulling the axle forward.
Back in the early 70âs I was next in line for a new unit at our place and my knackered Leyland Laird was replaced with a new Mastiff (whoo- whoo!!). On my first trip I noticed that whilst I could see down the whole near side length of the box-van trailer I was pulling, I could only see the front corner of the offside. I contacted the transport manager by phone from the first services I came to and told him of the problem. He replied that as it was a new unit I must be imagining things! I told him that when I got back I was not taking it out again until it was checked. On my return to base I took the unit to the garage which had supplied it and who did all our maintenance. The foreman fitter told me I must be mistaken, but when they did the measurements they found that the wheelbase was longer on the offside than the nearside. Apparently there is a locating peg on the axle which should marry up with a hole in the top spring, but this one had been fitted with the peg missing the hole by several centimetres and the shackles tightened with it sitting against the leaf of the spring instead. When correctly lined up the problem dissapeared. So much for Leylandâs quality control inspections! Both the TM and the garageâs foreman listened more carefully to me after that when I said I had a problem with the wagon.
Nevermind that crabbing rigid, did anyone see that crabbing dolly Lisa on IRT was pulling last night? Was a good 2 foot off the straight, ended up pulling off 2 wheels, was a entertaining watch as always.
Funny, I was thinking of exactly the same thing.
And surely it would have been better to have taken one wheel off the other side and used half the wheel nuts on each hub rather than run the dolly as a three wheeler. Or not?
Alcpone:
Nevermind that crabbing rigid, did anyone see that crabbing dolly Lisa on IRT was pulling last night? Was a good 2 foot off the straight, ended up pulling off 2 wheels, was a entertaining watch as always.
yes watched it,wonder if youd get away with strapping it up,and carrying on around the 25 to your next drop