Next was to set up the wheel toe, Richard had some poles with grooves cut into them. These were based on the ‘Smart String 4 Wheel Toe Alignment System’ that he had previously used when working for some racing teams. The Smart strings works by attaching brackets to the vehicle, supporting transverse pole on the front and rear of the vehicle. Then parallel lines are ran from the front to back to measure from. As we only had the poles we supported the poles on 4 axle stands 2 at the front to at the back. This really helped us set up a string box around the car to take measurements from. We didn’t have any geometry settings for the car so talking with Richard we decided a good base to start from was to have the front and rear toe in 1mm each side. This would give an overall toe of -2mm on the front and -2mm on the rear. By doing this the car would drive straighter and the back end would not kick out as easy on corners.
You can read more about the Smart Strings system here.
We firstly we had to find the centre on the steering rack and set the steering wheel straight. Next we set up the box around the car using the poles, one pole at the front one pole at the rear. We then ran weighted fishing line from the front pole to the rear pole creating a box around the car to measure from. Firstly we measured from the centre of the hub to the line on all 4 hubs, this was to get the same measurement from the hub to the line on all 4 hubs to make sure the lines parallel.
Once the lines were exactly parallel this allowed us to get a precise measurement from the front and rear of the wheel to the line to work out the toe in millimetres. The front toe was a reasonably straight forward to set up. With the steering rack set centrally it was a case of shortening the track rods either side until we got the front wheels to toe in by 1mm on each side with an overall toe of -2mm. One issue we had was that the track rod was too long and bottomed out in the track rod end. As there was plenty of thread on the rod we took 10mm of thread off the end of the track rod on both sides with a hacksaw. This stopped the track rod bottoming out in the track rod end and we could get the toe to measure correctly.
The first measurement of the rear toe showed we had -4mm on N/S and -1mm of the O/S. Unfortunately the rear toe set up was more difficult to sort out. With the Jaguar XJS rear axle this meant adding or removing shims between the front and rear mounting points of the lower suspension arms to the solid mounted Jaguar rear diff. We ended up adding some shims to the front mounting and removing them front the rear mounting point of the N/S lower suspension arm. This was to push out the toe on the N/S rear to give us -1mm on each side.