Specifications

What gearing do I use?
Gearing is made easy thanks to that nice bloke BrianG:
http://www.scriptasylum.com/rc_speed/_top_speed.html
Assuming you are wanting a fun, controllable setup, aim for 40mph with your setup. There are
options everything you need to input such as differential ratios, transmission ratios, tire size,
voltage, and specific motors. If your motor isn’t listed, you should know its kv rating however, so
you can enter it manually, same too with your tire diameter and anything else such as spur gear
size etc. All the options for Traxxas vehicles an feigao/neu motors are listed, so it shouldn’t be
too hard to figure out. For a speed machine, a top speed of about 60-65mph is a realistic target,
but it is easy to get carried away with the numbers you punch in, so remain sensible and be
realistic about what your setup can do. A ~2000kv feigao on 4s lipo isn’t going to exceed 40mph
without temperature issues; bumping up the gearing will only make this worse, as will using
more voltage. Excessive heat on a motor is very bad news, and as a general rule, you shouldn’t
exceed 180*F, or about 150*F on the esc, and 120-130*F on the lipos. This should be helpful as
a general guide to gearing and temps:
Hot motor + cool esc and batts = undergeared.
Cool motor + hot esc and batts = over geared.
Hot everything = way overgeared.
Warm everything = correctly geared.
Where can I buy all this stuff I need?
Head over to the 'Truck links' page and you will find extensive links to numerous online retailers.
Broadly speaking, besides the esc, motor and batts, you will require connectors for the motor to
the esc (3 male and female bullet plugs, 5mm or larger), battery plugs of your choice, and some
10-12 gauge wire. As I’m biased, RC-Monster is a great place to get most things, but larger
retailers like ImpaktRC and Amainhobbies also have most items. Shop around though, as many
of the smaller boat and plane/heli webstores also carry the items you require, often at lower
prices with more variety.
What type of pinion do I use?
Since the Emaxx and Erevo use 32pitch, or MOD 0.8 spurs, you require a 32pitch pinion (the
difference between 32p and MOD0.8 is so small that they are interchangeable). Motors with a
5mm shaft will require 5mm bore pinions (that’s most BL motors from Feigao and Neu), motors
with a 3.2mm or 1/8” shaft will require pinions with the same sized bore (bore meaning the hole
in the middle). It is ill advised to simply drill out a pinion to increase its pinion size, as this can
cause it to spin off centre, making a stripped spur or broken shaft more likely. MOD 1 pinions are
most often used on nitro conversions, though they can also be used on purely electric vehicles
when an especially small tooth count is required often, or when the user has issues with stripping
the smaller teeth on 32p pinions. When mounting the motor, make sure the screws are not too
long and do not touch the windings inside the motor. Also make sure that the mesh is not too
tight, as this can cause binding that will heat up the electronics rapidly due to the high load place
on the motor to spin the gears. A piece of thick paper placed between the spur and pinion before
they are pressed together (meshed) will give just the right amount of clearance. If you cant feed
paper in between them as you rotate the gears by hand, the mesh is to tight; if the paper goes in
all to easily, the mesh is too loose. A tiny amount of backlash or play is what you are looking for,
but it is important this remains the same as you rotate the gears, to ensure spur gear doesn’t
bind with the pinion at any point in its rotation.
I cant solder, what should I do?
Learn. All you need to know really in order to solder is that you need a hot iron (60-80watts is
more than fine, but 40watts is just about enough to do most things too, but takes a little longer),
keep it clean with a damp sponge or brillo pad (you can buy special tip tinner and cleaner too),
and use good quality lead free solder. A little extra flux often helps, but is often corrosive so be
careful. When soldering things like deans plugs, be careful as holding the iron in place too long