Nowadays most RC cars use oil filled diffs. Depending on your car it will have either one, two, or three diffs. The diff is an important part for your car, playing an important role in how the car drives. It is worth checking your diffs gears and oil regularly, and by changing the oil viscosity in the diffs, you can change the behaviour of the cars characteristics to suit your driving style. Please note that not everyone drives their cars the same way, and while people will advise on certain oil weights, you usually find people find their car handling worse. That’s why we always advise customers to try various weight diff oils to find out what suits you and your driving best. 

 

 

Having various diff oil weights allows you to tune your RC cars' drive train to how you would like the car to behave when entering corners and how the car behaves when accelerating. We recommend people check their car's mechanical functions all ok before each time they use their car. This along with regular maintenance is important before you look into your diff oil weights. If you have issues with the car's diffs, spur and pinion gears, suspension, wheel angle and poor movement of the suspension. Any of those will all affect the performance of the car and not show the true reflection on the possible benefits you could potentially get when you change your diff oil weights. 

 

Taking into account the above, once you have made sure that the chassis and the drivetrain are all working as they should, you can then start to look into changing the diff oils to get the car handling and performing the way you want. There are pros and cons to going thicker or thinner on your diff oil weights. So why don’t we look into differential oils and how they will affect the performance of your RC car. 

 

In most RC cars the diffs have a lubricant grease which will give you basic steering capabilities for hobbyist applications, so there is gains and scope with your cars capability by changing the weight of your diff oils. Changing your diff oil depends on how regularly you use your car but as a rough idea every few months if you are using the car regularly would be ideal. It is always best to check the diff oil and when replacing the diff oil it’s advisable to check the condition of the diff seals and replace if necessary.

 

The diff oil’s viscosity, or weight as is commonly known, will affect the car’s capabilities at cornering at different points during cornering. The diff oils will play a significant part on the performance of your RC car.

 

If you take the Traxxas X-Maxx  for example, that car runs 30,000 weight oil on the front diff, 20,000,000 weight oil on the centre diff, and 30,000 weight oil on the rear diff. 

 

Using thinner oil in the front diff from standard, it increases steering into corners of power. However if you go too thin on the oil it may make the steering become less predictable and can lose forward traction (and steering) during acceleration out of corners. If you have used thicker oil from standard in the front diff, it increases stability when braking into corners, but on corner exit it does increase steering on power. 

 

 

On the centre diff if you used thinner oil it would make the car more easier to drive on rough tracks, and will make the front wheels unload more when accelerating. It also gives you more off-power steering. If you used thicker oil on the centre diff it will help give better acceleration, and give an increase with on power steering which reduces your car understeering. If you go too thick with the oil however it will give you potentially too much oversteer when on power. 

 

On the rear diff by using thinner oil, you increase traction when in corner, but also increase steering going into the corner too! If you use a thicker weight oil it will reduce wheelspin and also decrease traction to the rear wheels during cornering too. 

 

As you can probably tell by now, there is quite a lot to be taken into account if you are looking to change your diff oil weights. There is no right weight oil in the diffs for everyone as everyone is different on how they drive their car. 

 

Hopefully this info helps a bit but by all means contact us if we can be of any further help.