I'm have a rough idea on a build that I'm thinking of doing but need help deciphering brushless motors. Originally I thought, the bigger the number of KV the stronger the motor. Not always the case. So can someone explain to me how to determine what's better? Reason for my question is everyone says Castle Creations. They seem to be fantastic motors but are the most expensive I've found. Can anyone help?

Truck its going on will be: E-Maxx 3905

**Also secondary question: I'm buying the Spektrum DX 2.0 after my wifes birthday at the end of the month. If I run two esc's and program them together with the remote will I have any issues? Or what is recommended to do this... Thanks a lot!!!!!!!

Higher Kv, more RPM's, less torque
Lower Kv, less RPM, more torque
(as a general rule)


The Kv value of a motor is in units of RPM/volt, so a 1000Kv motor, on 1 volt, will spin at 1000RPMs

Perfect! That explains things. Thank you very much!

Any thoughts on the second question?

Wow................ a new reason to buy something..............the old "after the wifes birthday present for myself"!

As Brain pointed out, less kv = more torque, more kv = more top end.

Putting a system into a 3905 (which is the brushless ready e-maxx as opposed to the 3906) will NOT require two esc's. You can have stupid, gonzo power with one motor and esc. The dual brushless setups you may have seen are either for show, or because they chose two motors that would be inadequate by themselves. I run the Mamba Monster 2200 kv system in my 3905 on 6s lipo (22.2v) and you dont need any more power.............trust me on this. Wattage output is in the 3500-5000 range. Roughly equivalent to 4-5 h.p. You can get a little less expensive setup and still have alot of fun...........people have run feigao's and KB's with lesser known ESC's with good results.

Here is an example of a setup that is a bit less expensive and will give you alot of fun, http://www.hobbycity.com/hobbycity/s...em_2350Kv/150A

Well, if there is no need to run two then I'll just buy the CC setup. Ultimately would you say thats the best?

Any idea on the top speed of your Emaxx with that setup??

"Well, if there is no need to run two then I'll just buy the CC setup. Ultimately would you say thats the best? "

Yes...............it is of high quality, and has great support. I have had two products warrantied by them, and one was a year old! Dont worry, i have had more than two of their products so their quality is good in my opinion. You can get the 2650kv or the 2200, both very powerful, the 2200 is rated for 6s and the 2650 4s. The 2200 is more powerful and will be faster on 6s.

Top speed is around 60.

i want to know which brushless motor to buy? are they all the same?

That is such a generic question, we need to know what it's going in, what your budget is, what kind of performance are you looking for?

DC brushless motors (unless you got a crazy setup), and no, they are not all the same

The 2200 is the one to get for monster trucks. The 2650 is a smaller motor aimed at racing buggies.

For starters the 2200KV on 4s is a really good setup.

This is the best system out there right now, you can't really beat it.

working with boats we use this for motor and batt setup

high kv motor - low volt batts
low kv motor - high volt batt

so a 1900kv motor on 4s will give you roughly  the same rpm's as a 1300kv on 6s, but then theres the size of the motor aswell, no point in using a motor for a 1/24 car in a 1/10 car, you'll burn everything up, then you have to take into account of all the gear ratio's

usefull info is usually

size of vehicle
batterys
gear ratio's
2wd or 4wd

lol At the guy who resurrected a 7 month old thread.