07/16/2026
💡 Baja Tech Tip: Not All Shock Fluids Are the Same
Did you know the factory-filled shocks in the HPI Baja are designed around a petroleum-based fork oil, not a 100% silicone RC shock oil?
While the stock fork oil gets the job done, many RC enthusiasts choose to switch to a 100% silicone shock oil because of its consistent viscosity, excellent temperature stability, and predictable damping characteristics. That means your suspension tuning stays more consistent from one run to the next and from one rebuild to the next.
For my Baja SBK build, I’m starting with JT’s 350 cSt using the stock pistons.
Why 350 cSt?
* ✅ The stock piston holes are very small.
* ✅ A lighter silicone oil allows the suspension to cycle more freely.
* ✅ It provides a great baseline before making spring or piston changes.
* ✅ It keeps the suspension from feeling unnecessarily stiff.
Remember, petroleum fork oil and silicone shock oil don’t use the same viscosity scale, so trying to compare them by “weight” can be misleading. It’s always better to start with a proven setup and tune from there.
For a stock-piston Baja SBK, 350 cSt has been an excellent starting point in my testing.
Suspension tuning isn’t about using the thickest oil—it’s about using the right oil for your setup.
What are you running in your Baja shocks? Let me know in the comments! 👇