Customers often ask us, "What kind of shock oil do I need for my RC car?" "Is shock oil the same as differential oil?"
Now we will introduce the difference between shock oil and differential oil, and how to choose it.
Both shock oil and differential oil belongs to silicone oil. Their main function on RC vehicles is to provide damping. In the RC field, “cst” or “wt” is generally used as the oil label.
The viscosity of silicone oil used in the shock and differential is different: the shock oil is usually less than 1000 cst, and the differential oil is usually between 1000~10000 cst. On the market, you can see that there are 20000, 100000 and even higher differential oil. The shock oil used in AK-917 is 500cst, and the differential oil is 20000cst. For RC cars with different proportions and models, the oil are also different.
With the increasing number, the viscosity of silicone oil is higher, the fluidity is worse, and the state is closer to solid. High-viscosity silicone oil is mostly used in parts requiring large damping but small oil drain volume, or in structures that cannot be closed.
The viscosity of the oil will decrease under high temperature, which means that the shock absorber and differential need to be maintained again to ensure that the quality of the oil remains unchanged.
For the shock absorber, the viscosity of the oil is lower, the reaction rate of the car is faster and the grip force is stronger, but the tire is easy to overheat.
The viscosity of the oil is higher, the reaction rate of the car is alower, and the grip force is weaker, but the tyres will be protected. The higher viscosity of the shock oil will make the RC car more flexible and easier to handle when turning.
When the grip force is good or the temperature is high, use the shock oil with relatively high viscosity;
When the grip force is poor or the temperature is low, use the shock oil with relatively low viscosity.
For the differential, the front differential will use differential oil with greater viscosity than the rear differential
Take the rear differential as an example:
The viscosity of the oil is lower, the grip force of the car is greater. It is suitable for the ground with poor grip. And the radius of the RC vehicle when turning is smaller, the stability when entering the curve is higher. But the acceleration is poor in the acceleration process after turning.
The viscosity of the oil is higher, it is more suitable for the ground with strong grip. The RC car has poor stability when entering the corner, but it accelerates faster when leaving the corner, and its steering performance is better when accelerating.
For sections with poor grip or large number of turns, use differential oil with relatively low viscosity;
For sections with strong grip or few turns, use differential oil with relatively high viscosity.
When the vehicle is driving, the rising oil temperature will weaken the damping feeling.
In order to avoid the feeling of damping reduction, the differential oil with a little higher viscosity can be used to run in with the differential before entering the race track to make it closer to the normal working temperature, so as to maintain a consistent damping feeling during the race.
The selection of shock oil and differential oil is also related to other settings of RC vehicles, such as control mode, volume of shock absorber, oil brand, temperature, etc. The most important thing is to feel for yourself and test to find the most suitable shock and differential oil for yourself.
To sum up, when selecting shock absorber oil and differential oil, please remember the following three tips:
- Select oil from the same RC brand to maintain the stability of oil quality;
- Understand the road conditions of the track in advance, and select the oil that is suitable for both the road conditions and the vehicle type;
- Before entering the race track, use the differential oil with higher viscosity to run in with the differential, and select the appropriate oil through test run.