Tracking Measurement for Tyres

Our tyre tracking is out. Can anyone help us with the measurements so we can re-align. For example, if we are looking at both the front tyres only - what should be the difference in millimetres front to back of each (front) tyre. And measurement in distance from the inside of one tyre to the other? Do we need to set them parallel? Is the consideration the same for the rear tyres? Any help appreciated. Many thanks
Cassie

Should have added - LR Defender 110 CSW with BFG AT tyres.

Take it to a propper place and get it done on their machine.....20 minute job and should cost no more then 30 quid but at least you will know its done properly and will save you a fortune in tyres.

Its surprising how much difference 2 degrees makes. When I had mine done after replace the steering arms it was only 2 degrees out yet the turning circle was affected and the steering felt weird. Afterwards it was like a new car

Thanks Sirus. Assume a 'no, no' to DIYin this case. But if stuck (in China), is there any guideline available? Will try local garage meantime.

0 to 6mm toe-in.

cassie, I did my own a while back.

basically I went for 0mm.

look at the vehicle head on, then measure the distance from the outside of the tyre to the outside edge of the other tyre in mm (front). then crawl underneath and measure the rear of the tyre in the same way (back). I got mine to measure equal and therefore parallel (assume 0mm) and not had any problems.

as Trewy said 0-6mm toe in, you could afford the front measurement to be a couple of mm shorter than the rear.

did you bend your trackrod?

hope all is well.

G

Cool!
Much obliged.
Many thanks.
Cassie

the only ajustment in the tracking on a defender is the track rod, which from memory should be 1230mm between the centers of the ball joints.
the only other thing to ajust is the drag link and that will just change were the steering whell faces.