[Espeefan]

Space plays a bit of a factor too. Smaller wire makes it easier to fit inside tight models. The larger gauge wire doesn't flex as much, which makes it harder to work with. I used to run 10 gauge on all of my other RC models, but they were higher powered trucks and buggies that could draw over 100 amps. For the big rigs like these, I would say 12 or 14 gauge wire would work just fine for the motors. They don't get so power hungry. I'll bet most trucks around the forum don't pull much more than 5 - 15 amps, constant load. You'll get a spike in current when starting a loaded truck, or under breaking, but that surge is only for a short time and smaller gauge wire can handle it just fine. Big construction models that are heavier and working harder will probably pull more current.