[woodcote]

I think the USA builders would love to know a few secrets to building over the bumps cars.

There’s loads of slot rally tips on forums based where slot rallying is (or has been) a big thing - mostly Spain and the UK. I included a quick intro in the fanzine produced for our our WHO Rally-Sprint a couple of years ago: https://slotracer.online/community/showt...8#pid14848

To be honest, the best way to build, test & tweak is to have a rally-style track surface to run the cars on. Something that’s the exact opposite to those lovely flat American wood tracks! Even just a small oval of half Ninco tarmac and half off-road would do the trick - both available in the US. That’s what I use. In the UK we can also grab some old Scalextric classic track for free and then create some elevations, gouge out the surface make rally loops etc.

Here are a few observations/tips: A rough surface constantly unsettles the car - randomly hammering each of the wheels up, down and sideways. Rally layouts often have lots of sharp turns (routed circuits may have tighter turns than a Scalextric R1). Any elevations effectively make the slot shallower and will catch any protuberance (or sharp corner) of the guide that’s forward of the pivot. Slot depth and width can be variable. The rail joins may not be smooth. Different track surfaces have difference grip levels and require a good all-round tyre. A punchy car is always good, but an overpowered car can be undriveable. An established slot rally competition car (eg any Ninco with suspension, SRC slot rally models) is a good starting point.