How to Set Gear Mesh on an RC Car in 3 Easy Steps

Nearly all RC Cars and Trucks contain meshed gears. Iit is important to properly set gear mesh for optimum performance. Improperly set gear mesh can cause a list of problems with your setup. The good news is that setting the gear mesh of your RC car or vehicle can be done quite easily. The gear mesh is adjustable in order for you to have the ability to change the gear ratio by using different pinion and spur gears.

Setting Gear Mesh in 3 Easy Steps

What you will Need

  1. Tools to adjust the Gear Mesh on your RC vehicle.
  2. A piece of standard size paper cut to 10mm x 50mm (1/2in x 2in) (Used for larger gears)

Step One – Loosen the Gear Mesh

Most RC Car’s allow you to adjust the gear mesh by adjusting the location of the motor. Find the location where you may adjust the location of the motor by loosening the fasteners that lock the motor in position. Once the motor is loose, be certain it is free to move in the direction that would allow for gear mesh adjustment.

Step Two – Set the Gear Mesh

Slide the 10mm x 50mm piece of paper in between the pinion gear and the meshed spur gear. Bring the two meshing gears together and apply a small amount of pressure to jam the piece of paper.   Using paper works best when you have a larger set of gears. For example 32 Pitch or Metric Module 1. (Mod 1)

If you have gears that are smaller, using a piece of paper will provide too much of a gap. In this case, bring both the pinion and spur gear together until it feels like the gears bottom out on each other. Relax the pressure and bring the pinion gear/motor away by a very small amount. The aim here is to bring the pinion gear away by about 15-20% of the overlapping distance. This will leave you with around 80-85% of overlap between the gears.

Step Three – Tighten the Gear Mesh and Check

The final step is to securely fasten the screws that allow you to adjust the gear mesh. Once everything is solid and locked in to place, quickly check the overlap of the gears. Optimal mesh is achieved when 80-85% of the gears are overlapped. There should be a small amount of space between the meshing gears where you can see light through. The 15-20% gap is important for proper gear mesh.

Symptoms of Improperly Set Gear Mesh

Improperly set gear mesh can cause issues within your RC car. There are only 3 possible outcomes after you set the gear mesh. The first outcome is that you have everything set correctly and nothing further must be done. The second outcome is that you have set the gear mesh too tight. The final outcome is setting the gear mesh too loose. In either case, it is important to make the correct adjustments in the gear mesh for best performance and reduced wear.

Gear Mesh Set too Tight

If you happen to set the gear mesh too tight, you may hear a grinding noise or in general excessive noise coming from the meshed gears. Your motor may be overworked due to increased load caused by the friction of the meshed gears. Lastly, a tight gear mesh will cause pre-mature wear of the gears. Typically, the pinion gear is made of metal and the spur gear is made from a form of plastic or nylon. In this case, the plastic or or nylon gear would wear out first.  To prevent further damage, stop the vehicle and adjust the gear mesh to be not as tight.

Gear Mesh Set too Loose

Gear mesh set too loose will also show signs and symptoms. However, with loose gear mesh, you do have to pay more attention to the signs as they are more subtle. One of the first signs of a mesh set too loose is backlash. Backlash is when one gear is able to rotate a few degrees until contacting the meshing gear forcing it to rotate. Backlash causes wear when you must switch the direction of motion frequently. Wear is produced by each gear accelerating and slamming in to the next gear when a small amount of momentum is built.

Another symptom of gear mesh set too loose is complete destruction of the gear. Unfortunately, this symptom will not provide you with much of a warning. I’ve gone through a few spur gears in my day from this one alone. A good way to prevent this is to check the mesh of the gears before driving your RC Car or Truck.

Lastly, after several runs of your RC Car or Truck, take a look at the spur gear. Determine if there is significant wear occurring at the tips of the teeth on the spur gear. Excessive wear at the tips of the teeth is a sign of gear mesh set too loose.


Use These Gear Mesh Tips to increase the performance of your RC Vehicle, transmission and reduce wear.


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