Just for reference, I have some pics of the "gear reduction unit" that I made:
The drawback for this is rotating mass, more general weight, and more friction. I think it might be a good alternative to an E-Maxx transmission, without the 2-speed.
SH Z-Car, Custom Crawler, 8s Savage,
12s XTM XLB 1/7 buggy,
4wd 4-link rear/IFS Pro4 truck,
Custom Hyper 10 Short Course,
Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz