Thread: Trailer Towing Question

Originally Posted by 123rover50

Well I had to experiment. Bit wet today so hooked up the rideon to its trailer. Offset the trailer drawbar and as far as this goes I can see no crabbing. So my theory was wrong. Dave and CC and others were on the right track.

(I cheated, I did mine with a lego model with rubber wheels on the tractor and a pair of plastic discs for wheels on the trailer then rubber on carpet for loaded.)

The tractor was a simple parallel pair of axles with a drive clutch on the rear axle. The trailer was a simple single axle job and the hitch was a ball socket hinge that could be shifted left, or right to just inside the wheel on the tractor and out to parallel with the wheel on the trailer. Let go on the carpet I loaded it up (both the tractor to maintain traction and the trailer for rolling resistance) untill the clutch started to pop and then reduced the load by about 1/5th

when you get loaded up (as mentioned in another post) according to lego on carpet physics

if you have the draw bar offset on the tractor its going to pull the tractor back on that corner and make it do a half crab half turning kind of motion, with the solid bar axle I used on the patterned carpet it turned out to be an interesting fight to see which one of the drive wheels wanted to maintain traction and provide the push (in the real world I guess you could force the issue by fiddle braking the tractor). When the wheel closest to the draw bar was providing most of the push it went straight, when it was the wheel on the far side the whole lot turned inwards, away from the outermost drive wheel.

If you offset the draw bar on the trailer if you drag the trailer wheel closest to the draw bar not much happens if you drag the outside wheel my tractor would either slip its clutch and remain stationary OR if traction was low and it was axle tramping the tractors rear end would skip inwards towards the trailer untill one of 2 things happened, either the tractor got enough grip to drive outwards away from the stuck wheel or the tractor would walk its way around inline with the draw bar by alternately stepping the back then hopping the nose around until it got enough traction to over come the resistance on the trailers stuck wheel.

Occasionally it simply snapped the ball socket joint apart, tore it off the trailer or tore it off the tractor.

Originally Posted by Blknight.aus

(I cheated, I did mine with a lego model with rubber wheels on the tractor and a pair of plastic discs for wheels on the trailer then rubber on carpet for loaded.)

The tractor was a simple parallel pair of axles with a drive clutch on the rear axle. The trailer was a simple single axle job and the hitch was a ball socket hinge that could be shifted left, or right to just inside the wheel on the tractor and out to parallel with the wheel on the trailer. Let go on the carpet I loaded it up (both the tractor to maintain traction and the trailer for rolling resistance) untill the clutch started to pop and then reduced the load by about 1/5th

when you get loaded up (as mentioned in another post) according to lego on carpet physics

if you have the draw bar offset on the tractor its going to pull the tractor back on that corner and make it do a half crab half turning kind of motion, with the solid bar axle I used on the patterned carpet it turned out to be an interesting fight to see which one of the drive wheels wanted to maintain traction and provide the push (in the real world I guess you could force the issue by fiddle braking the tractor). When the wheel closest to the draw bar was providing most of the push it went straight, when it was the wheel on the far side the whole lot turned inwards, away from the outermost drive wheel.

If you offset the draw bar on the trailer if you drag the trailer wheel closest to the draw bar not much happens if you drag the outside wheel my tractor would either slip its clutch and remain stationary OR if traction was low and it was axle tramping the tractors rear end would skip inwards towards the trailer untill one of 2 things happened, either the tractor got enough grip to drive outwards away from the stuck wheel or the tractor would walk its way around inline with the draw bar by alternately stepping the back then hopping the nose around until it got enough traction to over come the resistance on the trailers stuck wheel.

Occasionally it simply snapped the ball socket joint apart, tore it off the trailer or tore it off the tractor.

Interesting. You went to more trouble than I did.
Never seen a lego tractor.

Keith