Originally Posted by
sosidge
The M-05 ball diff uses 3mm diameter balls. Tamiya make them in various flavours, other manufacturers do them too. With Tamiya's own balls you are guaranteed a quality product which is not something you can say for every manufacturer.
Many people choose ceramic balls these days, personally I have never had an issue with good-quality steel balls, and I would actually choose Tungsten Carbide over ceramic. But that's just me.
Bear in mind that the thrust race is just as important as the main balls in getting a smooth diff, as is the cleanliness of the parts before greasing and assembly. I would always use plenty of black grease on the thrust and a smear of a thick silicone grease on the balls - Tamiya's own standard grease is rather thin, I use Much-More greases myself.
Would have agreed with you until I tried using quality ceramic diff balls. The diffs go much longer before needing a rebuild and don't need replacement. Actually are much cheaper in the long run. I've seen "cheapies" advertized, but would advise using those from R1Wurks or Acer racing. These are available from Speedtech or directly from Acer.
Have no experience with the Muchmore greases, but most TCS racers use Tamiya's antiwear grease. Not saying it's better, only that it works well and is in the kit.