Tamiya Twin-Motor Gear Box

This was good for my needs. Yes, the gears are plastic and the motor is cheap, so if you're looking for durable motors that need to operate at high torque, find something else. However, this was perfect for my needs in constructing a path finding bot.

(Posted on 12/23/16)

I use these for RC conversions of 1/35th tank models. They work well for this, but there's some things to keep in mind:


* The voltage ranges here are NOT suggestions. You WILL lunch the included motors running them above 3 volts. I honestly wouldn't even chance them on a 1s LiPo cell. Buy 6-volt motors as replacements, they're cheap as chips and you'll need them anyway. I got about two to three hours of use out of the included ones on a 6v NiMH pack.

* They're not gonna be very quiet.

* Don't look forward to high-speed operation. Something about the way these gears are designed makes them chatter when you spin this thing up too fast. Maybe boring out the gears and fitting it with tighter fitting bushings/bearings would alleviate this, I do not know. Or perhaps it's a side effect of how heavy my tanks are?

* The final drive gears are a bit on the fragile side and will shed teeth from time to time. Keeping them clean and well greased helps but due to how Tamiya has designed it there's a lot of force coming into a 12t output gear. Since I don't have the luxury of using the larger spurs as the output in this unit's highest torque configuration(the output shafts won't reach the drive sprockets while the housing itself clears the rear armor plate in this configuration) I'm often having to buy these things again just for replacement gears. This, again, may also be due to the loads I put them under. My tanks usually end up weighing about two pounds or so, all told, and moving something that heavy may very well be overloading the transmission significantly. There seems to be no documentation on just how strong this thing actually is.


Overall, it's a great little gearbox, but it has its flaws.

(Posted on 8/4/16)

I knew and own this product before but needed another and wanted to test first and good experience with RobotShop again and they delivered. Price is about the same as a well known online seller of everything but they are not in the motor gearbox business so I'm happy to see I've found my new supplier in RobotShop.

(Posted on 4/22/16)

Works great for our Rover. Bought extra as a backup just in case something went wrong before the tech fair. So far so good!

(Posted on 1/26/16)

Bolted to a piece of acrylic with a nylon bolt skid. I had to play with the balance because the motors are quite far back from the axle, especially in "high" speed configuration, causing too much friction on the skid. One motor gear has a split making that side a bit noisy. Driven by a DRV8833 with a single 3.7 V Lipo.
Would like to try with the "sport" wheels

(Posted on 3/16/15)

We have a mini Tamiya Tank but as one motor drives both treads there's little point in turning it into a robot because it wouldn't be able to turn...This gearbox has the same width and profile as the original gearbox so it was easy to swap it in.

(Posted on 1/12/15)

I'm using this gear set for a robot heating duct crawler I made to video inspect my ducts. Using it with RB-Tam-26 Tamiya narrow tire set, although I hack sawed down the wheel shafts by 1/2" to give the crawler a narrower profile.

The gear box and be re-assembled, if you are unhappy with the initial gear ratio. There are 3 configurations, but only 2 different gear ratios.

The only con, is the motors run at 3V. Keep this in mind if you are trying to hit a specific speed. But at this low voltage, you get more current loses. Otherwise, would have given it 5 stars.

(Posted on 6/17/14)