This evening marked the start of World Time Attack preparations, with a plentiful 32 days to go. First up I wanted to tweak the caster, as I’d only roughly estimated the radius rod lengths when I initially installed the traction bar resulting in more caster than I’d like and hadn’t bothered to adjust them since. I dialed it back a bit by lengthening the rods, but I’ll have to wait until I can run it down to the alignment shop before I can confirm the actual values.
With that done I ran through setting up the the bump steer, since when I put the tie rod ends in initially in a rush I only did some very rough measurements. I setup my backyard style bump steer gauges, and went to work:
Here’s the tie rod ends, set with 2 of the possible 7 spacers beneath the rod end, corresponding to roughly 5mm higher than a stock tie rod end.
The graph below compares the tie rod end in near stock location, with it in a raised location by approximately 5mm. The near stock location gave a large amount of toe in with bump travel, and based on the second set of measurements I’ll insert one additional spacer on the tie rod end to get moderate toe out in bump, tending toward zero/slight toe in at the extremity of bump travel (about 250mm hub centre to guard is where my car bottoms out), which should give much better turn in, and stability under brakes.
While I was working I also found that the rod ends on the front end of the radius rods are nearly running out of travel at full bump, so I’ll adjust them slightly tomorrow night, put one last spacer in the tie rod ends, then put it back together. Next up is the splitter install.
– Tom