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Jack knifed at 50!


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I think its good you shared your thoughts and worked out you were tail heavy. i tow big gensets weighing up to 2.5 tonne and know that swaying feeling, makes your chest tighten and your but grip the seat. I have never endorsed the accelerate out idea allways foot of gas and let things calm down. we had a few moments years ago with the disco ones. never really had a problem with the amazons due to the extra weight and stability.

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I don't know if this relates but my tow bar was set too low by manufacturer causing the front of my trailer to lift the back wheels when empty. At over 40 mph going down hill I nearly lost control as the trailer started snaking and I felt the back of the grafter loosing control. I slowed to about 20 and was ok but took the truck in next day.

Is your tow bar set ok or did you have a front load?

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I don't know if this relates but my tow bar was set too low by manufacturer causing the front of my trailer to lift the back wheels when empty. At over 40 mph going down hill I nearly lost control as the trailer started snaking and I felt the back of the grafter loosing control. I slowed to about 20 and was ok but took the truck in next day.

Is your tow bar set ok or did you have a front load?

 

I'm sure now I was tail heavy. The shorter sticks went in first at the back with the longer ones on the top with the thick ends at the front. and straps over the top. Thing is, cos we were lifting them in I wasn't thinking the same way I do when the forwarder loads with halt tonne butts and I'm careful they're balanced over the axles evenly. It was unlike anything I've experienced before. Totally out of control as soon a I started down that hill. Complacent and gassing too much in the yard - idiot!:blushing:

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This is almost exactly what happened. I drove four mile before the duel carriageway no probs, didn't notice it felt odd or anything.

 

[ame=http://www.youtube.com/watch?v=s4MQEYe4_0Y]YouTube - Unstable caravan-auto jack-knife. Test by Olle Nordström.[/ame]

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What causes snaking apart from loading on the rear of the trailer?

 

I say this as I first had it on an evenly loaded log delivery. It was great fun, soon as I hit 55mph. Rest of journey I did at just under 50. I assumed it was a combination of trailer and all terrain tyres on the (courtesy car) Defender. But, then a colleague had the same vehicle when her usual vehicle was in for safety checks, she got the snaking unloaded, at 65, and whacked it into the central reservation. She got grief for it and was told she had crashed as she was a "silly girl". I ended up with the vehicle again shortly after and sure enough it was rolling from side to side at 40mph. Luckily I was ready for it and just snaked my way down the A3. Why on earth would it do this without a trailer?

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the thing that i think causes the snake is the load compressing the rear trailer axle tyres a bit so the structural strength of the tyre sidewall is compromised, this wobbling and flexing in the sidewall is affected by the road surface undulations and causes a sideways movement. the trailer then pivots on its front axle causing a sideways pressure on the ball/hitch and away you go.

it can also be caused by other factors such as crosswinds

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there's yer problem...get a landy! glad your ok, that sounds like a recipe for underpant soup

I wrote a landrover off towing, it was a 90 model. Carrying a load of turf within weights legally on a large ifor trailer. Traffic cop(He was a nice one) said short wheelbase and then a long distance in between towing vehicle and 1st axle is excessive leverage when it doe's swerve and caused excessive loss of control. I was only doing 40mph.

The actual cause of the crash was the trailer had broken leaves in one of the axle springs. That caused the trailer to act unstable. One colleague was in hospital for a week , the other suffered a broken foot. I was ok but went to court for it and my boss(I was a subbie) got done for failing to maintain the vehicles. The land rover was onlly 18 months old. If I can obscure the sign writing in a mac program ,I will post pics.

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Fish tailing is caused by three things generally, having an uneven load, not enough weight over the "A" frame connector( ie the tow ball),or having to much weight for the trailer, sometimes crosswinds, slight load shifting, dodgy tyre pressures or erratic driving can be a factor, please remember never try to accelerate ,brake hard ,or steer out of the weave it'll only make it worse, just take your foot off the gas gradually , steer in a straight line, and dump the gears one after the other, without braking if possible, i've had quite a few artic trailers loose there brakes fully loaded running at 35tonnes + and it's the only way to stop them jacking out. By the way isn't 2 tonnes behind a micra kinda daft! StaySafe

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