sorry for not keeping in touch. The 4000 kv motor does pull the trailer with the stock pinion gear, but not so good. i understand that the tuck wont be able to go as fast. The rock crawler motor sounds like a good idea, but i'm not really looking to spend money, especially since i would never use than motor anywhere else. The small pinion gear is a good idea, but idk if electrix sells smaller ones. Right now im in contact with people that actually know what they are doing when it comes to knex, so maybe they will be able to make it lighter. For those of you that are interested, the trailer is a logging trailer, so that when i go camping i can pull sticks and what not around on my truck.
Any other suggestions would b great!! thanks everyone