advice needed motor + gearbox

[putyn]

Hello community i need some advice,

Recently i started working on a robot driven by two brushless motor(i want to participate in a competition and im required to use brushless motors), the robot will have differential steering.
in order to decrease the rpm and increase the torque i need to use some sort of gearbox - but im having troubles finding something to suite my needs

i was looking to purchase this kind of motor http://www.ebay.com/itm/320930230550?_trksid=p5197.c0.m619 which has a gearbox attached and to try to replace the dc brushed motor with my bldc one - but i can't find any informations related to the gear box ration only the rpm.

Did someone tried this before ? can someone suggest a better option, any idea would be appreciated

Thanks,
Vlad

[jwatte]

I think you're better off finding or building a dedicated gearbox. RC car stores may have something affordable.

Another alternative would be to get a motor with a low kV, use small wheels, and drive it with strong enough power to move the wheels straight!

[putyn]

Thanks for the reply jwatte,

finding a gearbox that will fit in my country would be hard and expensive (the motor i posted from ebay its three times more expensive) and buyin from RC sites its not ideal cause of very expensive shipping fees
last year we build our gearbox using gears we bought from a printer repair shop - but it was big and loud

buying an motor its not an option cause the motors are given to us by the organizers, last year we got a motor rated 5000kv and they can be powered with 2-3 lipo

[jwatte]

Well, you have to use a gearbox of some sort. If there are no RC enthusiasts in your country, and thus no RC enthusiast stores, you have to make your own, or see if a mechanical supply store could have something you can use.
Another option might be to build a hovercraft, and use one brushless motor for a lift fan, and then other for a drive fan. Who needs wheels, anyway? :-)

[putyn]

sort of a requirement the wheels - i will order those motors w/ gearbox and ill try to replace the motor