a lot of people told me that these gear motors are slow and not that good. the only problem i have had is that they do not have a standard output. but if you use the tires that are made for them you can cut and drill them out so that you can bolt other tires to them. as for the speed, it is because they have a really weak motor, i replaced it with the stock motor from a xmod and wow what a difference. they are fast and have way more torque than a servo. Great gear motor. is they had a 3mm output shaft they would be perfect.