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3x8x4 Ceramic Motor Bearing

Product Overview

The 3x8x4 Ceramic Motor Bearing (693ZZCE) is part of our motor bearing lineup which is specifically designed for performance and longevity in RC motors. We utilize *chrome steel rings that are polished to a mirror-like finish in order to reduce noise and vibration. Then you couple that with a very tight ABEC7 tolerance to ensure there is as little play in the bearing. We use silicone nitride ceramic balls (Si3N4) for a perfectly rounded slippery ball inside a nylon cage instead of metal so it doesn't expand under heat, allowing for more performance. Lastly, we use high-speed oil for nearly frictionless rotation and metal shields to reduce contact on the races and to keep debris out.

Specifications

ABEC7 tolerances allow the rotor to maintain its location while under loads.
Deep groove chrome steel 52100 rings with a premium surface finish, smoother than stainless steel for better performance.
Nylon cage instead of metal so there is no expansion from heat, keeping friction to a minimum.
Silicone nitride ceramic balls (Si3N4) for a perfectly rounded slippery ball.
Lubricated with high-speed AeroShell light oil.

Motors Used In

Reedy Sonic Mach 2: 1 per motor, also takes 3/16x3/8 non-flanged

Tips

Installation: These bearings are made with a very tight tolerance so it is common for the bearing not to slip right on due to the edges on the armature being scarred from a pinion. You may have to lightly sand the armature shaft to get the edges off while adding a drop of oil on it to put the bearing all the way on.
Shimming: Once it is time to replace your motor bearing, you may need to reshim the motor. Try to keep the shims it started with in the same location but it can be hard to do this. After assembly, you check the shimming by spinning the motor and then pushing the shaft in or pulling it out (you must spin it each time you check the push or the pull so the motor is in its magnetic center). There shouldn't be more than 0.5-1mm in each direction.
Lubrication: For proper lubrication, you should reoil the bearing with our bearing oil or grease every 20-30 runs to get the most life out of your Avid motor bearings.
Break In: It is always best practice to run in ceramic bearings so the ball creates a bit of a groove so the slippery ceramic ball doesn't skid on the race causing it to flat spot. We recommend putting your vehicle on a box and turning your throttle point up 25% and let the motor run without load for 5 minutes.

*Chromium Steel vs. Stainless Steel

All our bearings are made with Chromium Steel races because the surface finish is smoother than other materials such as Stainless Steel. This results in less noise and vibration allowing for better performance. Since our product line is focused on land-based racing, we are less concerned with rust and more with performance. This is why the most demanding bearings in RC, engine bearings, use 52100 Chromium Steel and not Stainless Steel races.

Bearing Maintenance

You should never use motor spray and especially not brake cleaner on any RC bearing. Those products make cleaning a breeze but at a price, because they are caustic and eat away the surface causing excessive pitting on the races. The best way to clean bearings is to use a citrus cleaner which you can usually find at home depot or even the grocery store and is safe to have on your skin. It takes a bit more work but your bearings will thank you. There are several ways to do it, an ultrasonic cleaner is the best to make a soak with but with our current Aura line having no seals you may pour the citrus cleaner into a bowl and put the bearing on a top shaft, diff outdrive, or idler pin so you can submerse it in the solution and lightly spin the bearing so any debris will work its way out. Once the bearing is smooth again, remove the residue left behind by the citrus cleaner by running water over them and then immediately dry them. We suggest using an air compressor to make sure no water is left but don't let the air compressor spin the bearing (very bad for the balls and races to be operated at such high RPM). Once dry, lubricate quickly to protect the bearings from humidity so you don’t accidentally run them dry. We suggest using Avid Slip Oil obviously.