MR33 Aluminum 7075 Hard Coated Pinion Gear 64P 48T

The MR33 motor pinions are one of our absolute bestsellers!
The pinions are characterized by perfect concentricity and are extra hard-coated for a long service life.
A grub screw for mounting the pinion on the motor shaft is also included.
Our MR33 motor pinions are available with 48DP and 64DP teeth

Pro tip: It’s always worth experimenting with different sprockets. In all classes where the final reduction ratio is not fixed, you should always have different ratios in your pocket to be able to react to different race tracks. Calculate the total gear ratio of your RC car as follows: Divide the number of teeth of your main gear by that of your motor pinion, and then multiply this by the internal reduction ratio of your model (see building instructions).

Formula: Main gear / motor pinion x internal gear ratio = total gear ratio

1️⃣ What is the total reduction ratio?

The total reduction ratio describes how often the motor must rotate so that the wheels rotate once. It results from the interaction of:

• Motor pinion (Pinion Gear): Sits directly on the motor.
• Spur gear: is located on the center shaft or the differential.
• Differential reduction (if available, usually integrated in the gearbox).

The formula is basically:

Total transmission ratio=(main gear motor pinion)×differential reduction ratio\text{Gesamtübersetzung} = \left(\frac{\text{Hauptzahnrad}}{\text{Motorritzel}}\right) \times \text{Differenzialuntersetzung}Totalu¨translation=(Motor pinionMain gear)×Differential reduction

2️⃣ Influence of pinion and main gear

• Larger pinion (more teeth) → less reduction → higher speed, less torque, higher motor temperature.
• Smaller pinion → more reduction → more torque, lower top speed, engine runs cooler.
• Larger main gear → more reduction → more torque.
• Smaller main gear → less reduction → more speed.

3️⃣ Example calculation

• Motor pinion = 20 teeth
• Main gear = 80 teeth
• Differential reduction = 2.6 (assumed)

8020=4\frac{80}{20} = 42080=4 $$4\times 2.6=10.4$$

→ This means: The motor rotates 10.4 times so that the wheels rotate  1time

4️⃣ Practical effects

• Smaller pinion or larger main gear → better for off-road, crawlers, high torque.
• Larger pinion or smaller main gear → better for on-road, speed runs, high speed.

5️⃣ Important tip

Alwayspay attention to motor and controller temperature when changing pinion/main gear – too little gear reduction (too fast setup) causes the motor to overheat quickly.