Pure Brainstorming. Outrunner experts HELP!

[MetalMan]

Outrunners are excellent choices for lower-budget setups. For your truck, we shall determine a good kv.

Plugging the numbers into BrianG's "Parameter Solver"
Differential Ratio: 38/13 (2.923)
Transmission Ratio: 1
Spur: 1
Pinion: 1
Voltage: 7.2v (although I would use something more like 7.0v just to better estimate the loading on the battery)
Motor: leave blank, this value is what you want to find out
Tire diameter: depends on the tires you use obviously, but in general 1/10 trucks use 4" tall tires
Top speed: something like 30-35mph should be about right for a 4wd 1/10 on 6 cells

The result: a kv of ~1200 would be great.

As Metallover said, a 36mm OD is a good choice. In terms of outrunner specifications, that would mean the motor will have a stator diameter of about 28mm. As for stator length, I think 26mm should be good.
For example, the Axi 2826/8:
http://www3.towerhobbies.com/cgi-bin...?&I=LXPPX5&P=7
Its kv at 1130 is a bit on the low end for 6 cells, though.

From Hobby City, this:
http://www.hobbycity.com/hobbycity/s...r_Eq:_AXi_2826
Only problem with that is the 4mm shaft, where 5mm is more standard. 5mm is also the inner diameter of the drive cups that the dogbones go into.