Let's Make Robots!

maximum weight tamiya gearbox?

What would be the maximum weight i could put on the tamiya twin motor gearbox without stripping gears or roasting my motors? I've found out that my base is going to be a bit heavy......


Also, does anyone know what the dimensions of the gearbox are? LxWxH? any help appreciated. thanks.  

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Here's the data sheet for the Fabuchi 130 RA which powers the Tamiya Twin Motor Gearbox 


If you are using an L293D or it's equivalent to drive the motors you may want to consider either a voltage divider or replacing the motors with ones that can take 5+ volts that that type of dual H-bridge puts out.

 Pololu.com stocks two motors that are direct replacements for the motors that came with the Tamiya gearbox, one is good for 6v and the other is good to 12V. I recommend the 12V version because it's better to over engineer a bit instead of wondering what will burn out, torch up or blow first.


thank you mech. data sheet helps. What i'm really trying to find out is what the maximum weight that my bot can safely be is....

I used some fairly thick plexi and he is coming out to around 2 pounds or so... just under 1kg, but that is just with the mounting hardware.. I have yet to add batteries, my arduino, driver board, servos, etc... would i be safe with 3-4 lbs? or should i try to keep him under 3?

If you support the axles as close to the wheels as possible and use the highest torque gearbox setting you should be ok with a 2kg robot. It will be slow though and don`t expect it to climb hills.

My robot turned out too big for its motors too :(

Wow, 2kg? thats like.... 4.4 lbs here... my robot turned out to be 1.3 lbs, a little more than half a kg. with any additions i might add, he will come up to just about 2lbs. I think i might be just fine. thoughts?

thanks for the response ezekiel! 

You should be fine then. What are you using to drive the motors?

Im going to be using a SN754410 that i made my own board for... I have no idea at this point whether it is going to work or not.... but i'm pretty sure it should be ok. I dont know if i need to be capping the motors on this one though... i've heard there is a lot of noise with these ones and adding 3 separate caps helps with that... you guys really think that is necessary?

 Since I have your attention, I might as well ask your thoughts on this as well.... my datasheets say this driver needs 5v in and these motors work best at 3v even. going up to 5v will seriously decrease their lifespan.... I'm ok with that, because i can order some of the 6v ones from pololu for next to nothing. What do you guys think about using a 9 volt with a 5v regulator? I've used them in the past to charge usb devices, but they get a little hot, and i dont know what kind off electrical noise they might put out.  I think i have some 7805's laying around here somewhere....