These jigs complement the suspension plates, enabling you to set these squarely and at the correct wheelbase.Â They may be used on any 4-wheeled vehicle in which the standard type of W-iron is being used, whether it be fixed, compensated or sprung. One set will last a lifetime – if you are careful!
The smallest wheel base is 6ft. This uses the end hole marked 0 and the fist hole on the other side of the logo marked 6. Â The get a 6ft3in wheelbase you use the hole marked 3 (for 3ins) and the hole marked 7. Â This means that the first hole is 3mm to the right of the original hole, whilst on the other side the second hole is 4mm to the right of the previous hole. Â Hence the distance is actually 25mm, which is a scale 6ft 3ins.Â
So the long wheelbase set up shown in the photograph which should be 19ft 6ins, uses the 3rd hole on the left marked 6 and the hole on the right marked 21. Â You can work this out from 19ft (x4=76mm) plus 8mm on the right, minus 6mm on the left leaving 78mm which scales 19ft 6ins.Â
Note that 20ft 9ins, and 21ft 6ins and 21ft 9ins are not possible.