The Yokomo RP-113425 RP Ultra Shock Oil #42.5 is an RC-scale silicone oil intended for use in shock absorbers and dampers. The product is supplied in a 40cc bottle and is color-identified as blue to aid quick selection during setup. The RP Ultra series has been renewed with finer viscosity increments to support more incremental tuning steps.
Role in setup: This oil adjusts the damping characteristics of an RC car’s suspension by changing the internal flow rate of the shock assembly. Using a heavier or lighter shock oil alters rebound and compression behaviour, allowing measured changes to handling without altering mechanical parts.
Installation and handling: Replace or top up oil by disassembling the shock body per your shock manufacturer’s recommended procedure, drain old fluid, then refill and bleed air bubbles before reassembly. Keep the bottle capped when not in use and avoid contamination from dirt or grease to preserve consistent damping properties.
Tuning notes: Use the RP Ultra Shock Oil #42.5 when you want a mid-range damping response in the RP series scale, and make incremental changes between adjacent viscosities to judge handling differences. Track conditions, spring rates, and piston holes also affect overall damping, so change one variable at a time and document results.
Copyright © 2008-2026 rcjaz.com All rights reserved
