Motor Sizing Help Please

[RoboEagle]

Hello All,

I just want to start out by thanking this website for the great ideas and threads that i have been reading

I'm designing a tank-style robot that utilizes a treads system, and was kind of struggling in finding a decent light/powerful motor for the drive system. I am using a 5" diamater wheel for the treads to sit on, along with 1" diamater tensioners. Application specs dictated the motor specs to be the following:

62.5 lbf.in rated torque
233 RPM speed.
12 V(based on battery)

Thanks to some of the earlier threads on this website, i visited some websites such as http://www.robotmarketplace.com/products/ame_motors.html, but didnt seem to find anything close to those specs. The issue that im running against is that the more powerful the motor im getting, the heavier the battery is getting. So is there an alternative to DC gearmotors in this situation? Any advice/recommendations? are there any other good websites/vendors for such motors?

Thank you in advance!

[MangoBot]

polulu has plastic, and metal geared motors, you may find one, and yes always remember the heavier the motor, the more expensive motor, the cost grows exponentially when you have too heavy of anything.