Motor gearing is one of most important tuning options that you can play with on the SC10. Changing the gearing of your SC10 affects many things, including: Top speed, acceleration, motor temperature (motor life), and run time. Gearing will be different for everybody depending on type of motor, track conditions, and driving style.
The easiest way to adjust motor gearing is to change the pinion gear. The pinion gear is small gear that fits on the shaft of your motor. The pinion meshes with the spur gear. By changing the pinion gear, you should be able to achieve the gearing you want under most circumstances.
Most of the SC10 RTR kits come with a 87 tooth spur gear and a 20 tooth pinion gear. We suggest sticking with the 87t spur and experimenting with the pinion gear. Your first concern when looking for the right pinion gear is motor temp. If your motor is running too hot to the point where you have to stop every 5 minutes and wait for the motor to cool down, you may want to gear down from that pinion. There are some other things you can do to control motor temp but gearing down is the best way to control temps (see Checking and Regulating Motor Temp). Remember, if you can't touch and hold the end of your motor can for 3 secs, then your motor is probably too hot. By following this rule you will be sure that you are not damaging your motor.
The second thing you need to adjust gearing for is the track you are running on. Does your local track have a long straight away? Does you track have a lot of stop and go action? Are there jumps that you need to hit but don't have much room to get speed going? These are all questions of torque vs. top speed. The most important things to gear for in terms of the track are:
1. Are you getting the most out of your SC10 on the straightaways? Straightaways are the best places to pass your competitors and you don't want to be losing ground here. I would say to error on the side of less top speed for beginners but as you gain more experience, you will need those extra RPM's.
2. Do you have enough torque to get out of the corners and prepare for crucial jumps? I know on my local track there are two jumps that you NEED to hit. If my gearing is too high, it makes it difficult to get up to speed and I can't hit those jumps. When I gear down, it is much easier to get up and hit the jumps, saving me some time on every lap.
The main issue here is gearing your SC10 to a point where it can do everything you need to do on the track, without threatening dangerous motor temperatures. Everyone drives a little different. Some like more top speed with more sliding around corners. Others prefer more torque with solid traction through turns. First you need to decide how want to drive, then look at what the track demands. After you have a pinion gear that feels right, check your motor temps to make sure you aren't doing any damage.
Recap:
Start with the 87t spur/20t pinion if you are running the RTR motor set up. Gear the pinion up if you are experience cool motor temps or not enough top speed. Gear the pinion down if you are having hot motor temps or not enough torque. You should have an array of pinion gears in your tool box so quick changes based on track conditions can be made.
If you are running a modified set up, like the Castle Creations 5700kV motor, then you will want a smaller pinion gear for most track setups. We suggest starting with a 87t spur and 17t pinion gear and go from there. From our experience, this motor runs fairly hot but the 18t is necessary to get the top speed we need during races.
Please share your motor and gearing setups for your SC10 in the comments section below!