Short Course PR Racing SC-201 Main Sprocket 77T

Main crown, 77T p48, optional, made of composite, valid for the Short Course SC-201 PR-Racing chassis.

This crown is mounted in place of the original 83T crown included in the SC-201 kit.

How does fitting a main sprocket with fewer teeth affect the PR-Racing SC-201 chassis?

The PR-Racing SC-201 chassis originally includes an 83-tooth (83T) composite main drive sprocket. This sprocket directly receives the power transmitted by the motor pinion, which is usually made of aluminum or steel.

If we don't change the number of teeth on the engine pinion and simply reduce the number of teeth on the main sprocket, in this case from 83 teeth to 77, we'll be lengthening the final drive ratio of our transmission. In short, we'll have a car that will reach higher speeds. It will take a little longer to accelerate, it will have less power or torque, but in return, it will rev a bit higher, achieving greater top speed.

What precautions should we take when mounting this 77T sprocket on the SC-201?

Firstly, it's very important that you correctly fit the 77T sprocket to the motor pinion you're going to use. This sprocket operates at a 48 pitch, just like the original sprocket, so we must ensure that the sprocket engages the motor pinion with the correct clearance, that is, neither too far apart nor too close.

On the other hand, since this PR-Racing SC-201 racing chassis typically uses LiPo batteries and brushless motors, it's highly recommended that whenever you lengthen or increase the gear ratio (as happens in this case when using a smaller sprocket, if you don't change the number of teeth on the motor pinion), you monitor the motor temperature. If it gets too high, you'll need to adjust the gear ratio again, shortening the gearing. This will help prevent motor or speed controller problems.