[CustomRCmodels]

To get a nice operating ( drivable ) truck there is now way around a gear-reduction .
Just lower RPM motors or limiting the power to the motor via endpoint-settings on the transmitters , adding weight and such is just cheating and you want be happy with it .
It would be like on a real car or truck in which you are trying to take of in the highest gear with only applying very little throttle . You don’t have power plus you sucking up the fuel .
The idea behind gear-reductions is not only the slower more powerful , plus much more efficient ( less current draw from the battery ) driving , but also the braking .
We saw this again this year at Indy , driving up and down the bridge , you could tell right away who had gear-reductions in his truck . A higher gear-ratio gives you also better braking .
As for the Tamiya drive-train based trucks , I used to use my self-made 55 turn motors
( way before the lathe-motors and crawler motors were available ) in combination with a self-made 3:1 gear-reduction . This resulted in a actual speed-reduction of about 6:1 ,
since a 55 turn motor creates about ½ the rpm as a stock 27 turn motor ( 8000 rpm vs 15000 rpm ) .
This type of reduction was just the right speed for the Tamiya 3 speed based trucks .
When Carson introduced there original ( plastic housing ) 4:1 reduction , that alone wasn’t enough , but a good start , even thought a lot of guys used them , some also with the combination of a 55 turn motor which gave you about a 8:1 speed reduction .
Back then , together with RIC from PMD , we created the stronger , aluminum casing , modified Carson gear-reduction and I made some changes to the gearing ( additional ball-bearings ) . This GRU is a nice choice if you don’t have the room inside the cab , but room in your frame .
Now with the introducing of the Tamiya MFU unit , the idea with the lower rpm motors doesn’t work so well anymore , since the MFU is tailored for a 27 turn motor and if used with a higher turn motor ( lower current draw ) the effects , down/up-shifting , sound-effects , drivability , just don’t work as good .
The choice here would be to stick with a 27 turn motor and do the speed reducing via gear-reduction only.
Since I never was a friend of these cheap Mabuchi motors , I went with 27turn motors in a modified motor-can ( adjustable brushes / timing and ball-bearings ) , either self-made , by using the guts out of a Mabuchi motor and installed in a modified motor-can or using the Orion 27 turn Rush series motors , which are now hard to come by .
Therefore I am using now the 35 turn Integy crawler motors with a 5:1 gear-reduction ,
which seams to be just the right speed .
Besides the ready to install gear-reductions from PMD or RC4WD , there are plenty of options these days to make up your own gear-reductions from air-plane gear-reductions ,
or gearboxes from crawlers and such .

Maybe we should make a “sticky” out of this , since I would have a bunch of info’s to contribute to this subject , including website links , since I have a bunch of these info’s cluttered all over my website and these questions about motor’s and gearing seam to keep popping up regularly.