How can you tell gear pitch?

[Coelacanth]

Is this something you can tell by looking or at least comparing them?

The spur & pinion I've installed in OptiMutt--with Robinson Racing spurs--uses a pinion with tiny teeth shown on the left. To the right is something else, and in the middle is what I believe is a typical 80's pinion gear used with the original Optima series. I know the common ones are 32p, 48p and 64p. Are the left-most gears 64p?

Thanks.

[Mr. ED]

The one on the right is kyosho's typical 0.6M (metric Module) Nowadays available from HPI and Novak by the way.
The teeth are slightly larger than 48dp (imperial). 48 dp is what you have on the left.

32-48-64 dp I believe stand for 32-48-64 teeth per inch. So the higher the number the smaller the teeth.
64 dp is real tiny and only used for 1/12 pan cars in general

when in doubt of the spur pitch, run a known pitch pinion over it by hand , if it meshes wrong, you'll be able to tell easily.

There are also 0.5m pinions which I think are even closer to 48dp than the 0.6m's. But I would not advise to mix them with 48dp spurs.

[Coelacanth]

Thanks Erik...I know I've seen 48 & 64-pitch RR gears so I wasn't sure which ones I had. If I need additional pinions for the OptiMutt car, I'll make sure they're 48p. Cheers!

[EvolutionRevolution]

The one on the right is kyosho's typical 0.6M (metric Module) Nowadays available from HPI and Novak by the way.
The teeth are slightly larger than 48dp (imperial). 48 dp is what you have on the left.

32-48-64 dp I believe stand for 32-48-64 teeth per inch. So the higher the number the smaller the teeth.
64 dp is real tiny and only used for 1/12 pan cars in general

when in doubt of the spur pitch, run a known pitch pinion over it by hand , if it meshes wrong, you'll be able to tell easily.

There are also 0.5m pinions which I think are even closer to 48dp than the 0.6m's. But I would not advise to mix them with 48dp spurs.

64dp is also used for indoors racing a lot on any on-road car. There's also 0.4M (metric module), which is really close to 64dp and can be mixedwith it despite slightly higher wear.

Any other modules should not be mixed due to either not mating or very quick gear breakage.

[RichieRich]

You can mix 32 pitch with .8 module as the difference is very small. You definitely can't mix .6 module with 48 pitch as those are not even close. Also, save this:

Pitch conversion formula.

D = Diametrical pitch (ie 32, 48 or 64 pitch)
M = Module (ie 0.8, 0.6, 0.4)

M = 25.4/D
or
D = 25.4/M

[jwscab]

you can actually measure the pitch by measuring between teeth pretty easily as well. but you need to measure at the root of the tooth.

32 pitch, well, 32 teeth to 1 inch, so 1/32" between teeth. this is for diametrical pitch gears.

for mod gears, it's really the measurement between teeth in mm, so .4mm spacing, .8mm spacing, etc.