Met­ric Mesh

What’s the dif­fer­ence be­tween “48 pitch” and “met­ric 48 pitch” gears, and how can I tell what’s in my car?

RC Car Action - - TECH CENTER -

A gear’s pitch refers to its tooth size. The smaller the num­ber, the big­ger the tooth. In RC, we most typ­i­cally see 32 pitch (com­mon in high-power ve­hi­cles), 48 pitch (most 1/10 scale), and 64 pitch (gen­er­ally seen only in pan cars). Each of these has a met­ric equiv­a­lent, or at least a rough equiv­a­lent. The cor­rect term for the tooth size of met­ric gears is “mod­ule.” A 0.6 mod­ule gear is re­ferred to as “met­ric 48 pitch” but is ac­tu­ally 42.3 pitch. Stan­dard 48 pitch and “met­ric 48” pitch gears will not mesh to­gether prop­erly. Com­pe­ti­tion cars typ­i­cally have stan­dard 48 pitch gears, while sport cars from Tamiya and Kyosho are gen­er­ally met­ric pitch.

As for telling met­ric and stan­dard pitch apart when uncer­tain, the best thing to do is check your man­ual and the gears them­selves for any la­bel­ing that in­di­cates met­ric or stan­dard pitch. If that doesn’t pro­vide the an­swer, try mesh­ing the gear with another pin­ion or spur that you do know is stan­dard or met­ric. If the gears mesh smoothly, you’ve got a match. If the mesh feels notchy, you’ll know you’re mix­ing met­ric and stan­dard pitch.

Tamiya cars and trucks, like this TT-02B, typ­i­cally have met­ric gears. Both of these gears have 21 teeth; the sil­ver gear is “met­ric 48 pitch” and is no­tice­ably larger than the stan­dard 48 pitch gear.

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