TXT-1 Gearing

[VTBruiser]

Can anyone help me better understand the gearing of a TXT-1 ?

Tamiya lists the gear ratio as 34:1

Is this overall including stock pinion and axles?

I've run a few searches and seem to be getting conflicting info

The axles:

A 15T Bevel gear turns a 18T Bevel Gear connected to a 16T Drive gear that turns a 28T Ring gear

18T / 15T x 28T / 16T = 2.1:1 axle ratio

The transmission, however, appears to be too complex for my limited math skills:

A 15T Pinion gear turns a 40T Spur gear with a smaller 15T gear that turns a 27T Long gear with a smaller 15T gear that turns a 27T short gear with a 16T smaller gear that turns the 30T Output shaft gear

40T / 15T x 27T / 15T x 27T / 16T x 30T / 16T = 15.1875 transmission ratio

2.1 x 15.1875 = 31.89375:1 overall "crawl" ratio

I would be extremely grateful for any assistance

 

[HawnMT]

I don't remember all the exact numbers but the 34:1 is the final drive ratio with the 15T pinion. The trans itself (minus the pinion) is ~6.78:1.

The axle is as you have it a 2.1: 1 but the calculation seems weird to me. The bevel gears play no part in reduction because they are the same. Only the drive gear and the differential ring gear make up the reduction.

 

[VTBruiser]

I don't remember all the exact numbers but the 34:1 is the final drive ratio with the 15T pinion. The trans itself (minus the pinion) is ~6.78:1.

The axle is as you have it a 2.1: 1 but the calculation seems weird to me. The bevel gears play no part in reduction because they are the same. Only the drive gear and the differential ring gear make up the reduction.

Thanks HawnMT

IIRC, the bevel gears are both 15T in the original Juggernaut and offer no reduction

When they were redesigned for the Juggernaut 2, Tamiya kept a 15T on the "long" bevel but changed to a 18T on the "short" bevel

Therefore, I do think the newer style bevel gears play a small part in the gear reduction at the axles

In any case, I'm still a little confused with the math so if anyone thinks they can help straighten me out in this area please feel free to give it a try