I’ve had a chance to run the car and thought I’d post an update.
The shocks fitted to the car came from an Ultima Pro. As received, they were in great shape and leak free so I didn’t bother to open them. On the bench, dampening seemed to be about right. On the track, however, they were all wrong; a little over-sprung and a lot under dampened – especially at the rear. The car bounced like a basketball. The rears were fitted with gold springs (.046” dia. wire, 13.5 coils), red pistons and something like 20 wt oil so I rebuilt them with AE silver springs (.041” wire, 14.5 coils) and Losi 30 wt oil. For the fronts, I just swapped the gold springs with AE bronze (a little softer rate) and left the shocks unopened (dampening is little soft but probably close to right). On the track, the changes were immediately apparent; the car handled the bumpy sections very well and stayed planted overall. Still not perfect but it’s going in the right direction.
Next, tires. I like to run Proline Bow-ties as they seem to work reasonably well on loose or hard pack dirt, clay and even in the sandy sections of my very ungroomed backyard track. The wheel/tire combination fitted to the car came from the Turbo Scorpion rere and although the rear tires may appear to be Bow-tie copies, they certainly don’t grip like them. Straight line traction is good but side grip, especially on hard pack, is very poor. As a quick test, I mounted a pair of Bow-ties on wheels from my RC10 (replacing the Ultima’s wheel hex adapters and screw-pins with a wire pins) and side grip improved drastically.
So, this is where the car is at the moment. I’ve ran 4 packs before it started to rain again. The shocks still need some tuning.
Oh, and another note on those Turbo Scorpion rere wheels; they’re as soft as butter. I have one front that’s bent and the rears have the outer edges shredded by the front tires kicking up small rocks that are prevalent in the soil around here. They may look pretty on the shelf but they’re probably not the best choice for a runner. Anyway, the rears are currently in an acetone vapor bath so I can remove and replace those Kyosho tires. While the tires are removed, I’ll mount the wheels in the lathe and see if I can clean-up those ragged edges.
