Let's Make Robots!

windshield

Windshield wiper motors, have you tried'em?

Have any of you experimented with windshield wiper motors? I know they've been used in budget robotwars fighters. I just need to get an idea what kind of strength they have (with the original gearbox).
Will it be able to pull 20 Kg vwith a 20 cm diameter wheel mounted directly to the output shaft? what abot 50 Kg? -or a 100?