Tech info from the RCRA EP OnRoad Australian Championships.

Regarding the XRAY X4'25, it was my first time using the Solaris spec tires in combination with the RC Maker cleaner and additive. Thanks to the Wednesday night club race at Boronia Radio Controlled Car Club, I was able to get a good feel for the tires and their handling right away – especially since Boronia had a similar surface and grip compared to Templestowe Flat Track Racers. Here’s my main takeaways from running this tire and on Australian grip levels for the last few days:

  • Chassis. Myself and Michael Stone went back and forth between carbon and alloy, and we both preferred the handling of the optional 1.5mm alloy chassis, as it provided the best corner speed and overall pace.
  • Optional glass fibre topdecks. This new item has been my go-to for low to medium grip asphalt tracks throughout the season as they greatly improve mechanical grip. We did use a rear topdeck on the front to improve the initial steering response.
  • On the Wednesday night at Boronia, in cooler temperatures, PSS was my preferred damping choice. Either 2 hole with 450 oil, or single hole (one hole glued shut) with 375 oil. However, in the extremely hot track temps at TFTR during the race, standard shock pistons delivered faster laptimes, as the car didn’t’ feel as stuck with them. In the end, I settled for 4x1.1 with 400 oil.
  • Upper arms. We initially had good luck with the optional full plastic upper arms, but as the grip levels increased, we settled for the kit S CFF upper arms for improved response.
  • Lower arms. We opted for the new optional G lower arms. Because of their stiffness, they stay more consistent especially in hot weather conditions, and also make the car more precise to drive.
  • Tire prep. My car felt the most balanced when tires were thouroughly cleaned with the Dominator cleaner before applying the additive. 15-20 minutes with warmers set at 75 degrees. I re-applied the additive half way through that time, and wiped the tires dry with a micro fibre cloth before going to the track.

Source:

A. Hagberg