I gained some motivation today and decided to brave the cold of the garage. It was a very productive day as I managed to convert 2 of my rear radius rods to be adjustable. I’ve already fitted them back onto the car and at some point in the future I will attempt to adjust the rear axle position to hopefully stop the car pulling to one side. However I don’t plan to do this till I’ve fitted some adjustable front wishbones.
The other item I was working on was making a bump steer gauge. If I get a chance I’ll try to remember to take a photo of it but it was pretty simple to make out of a few pieces of wood and some spare 16mm square tube. The most expensive part of it would have been the dial gauge but as I already had one on these it didn’t cost me anything.
From taking measurements of the actual bump steer I discovered that it wasn’t quite as bad as my original front suspension model, but it’s still not very good. Once I had the real measurements I made a slight adjustment to the model to get it to match the real data (my measurement of the steering rack height was not correct, only 0.6cm out). The graph below shows the original and updated model along with the real data and hopefully the ideal once the modifications have been completed. From the chart you can see that there is a slight curve to the data and this is caused by the rack being to wide. I plan to make the rack 5cm narrower, which is the most that can be realistically achieved. As luck would have it this pretty much removes the curve from the line. To make the line horizontal e.g. no bump steer I need to either raise the point the ball joint mounts onto the steering arm by 1.4cm or lower the steering rack by 1.4cm. Due to the design of the front chassis the easiest option will be to alter how the steering rack attaches to the steering arm.
