For the past 6 months we've been testing new parts and a few geometry changes. The biggest one is the 3 gear transmission that many other companies have available and an option. This option is available for us via the release of the JB Carbon 3d printed gear box on Shapeways. The results are astonishing and I firmly believe with just that simple update we are now competitive on every major surface except for perhaps astroturf and extreme high grip dirt.

On higher grip dirt surfaces I immediately noticed:

  1. Much more stable under braking.: I was able to increasebraking EPA to 85% from 75%.
  2. Smoother throttle transition: If I got the car sideways I could drift out of it much easier and consistently.
  3. Acceleration through bumps much approved.
  4. Landing greatly improved.: Could easily land off-axis and the car would settle out while even on power. Before I was always waiting for the car to settle before applying power again.
The lap times proved a .4-.5 second gain across the board. I broke my previous personal best by over 8 seconds, and top 15 average lap time was .5 faster than I had ever been before. All this gain without making a single change to the chassis setup.

The setup is what I've been running for months across multiple of surfaces. If your tires are right, this should be a good start, consider it a baseline. Once you've selected correct tires, then adjust the oil and perhaps a smaller rear roll center change for the conditions and you should be 98% there.

Here's the corner weights of the setup to help reproduce it:

Source:

J. Kirkwood

Pit Tables, RC Car Setup and Analysis