Originally Posted by
Chuck 21
The picture above is a true example of over thinking a mid motor
R/C car...
I designed the first mid motor RC10 right after they first came out from
AE and there is no need for an idler gear at all, it is a total waste of
time and extra moving parts.
All you have to do is flip the trany around forward. Then you drill out the
top shaft hole on the trany case so you can put the top shaft out the
oppisite side of the trany case. On the old hole side you cover it with a
piece of servo tape to keep dirt out of the trany & bearing. Then you put
the motor plate on the same side as the top shaft is coming out. Now
your motor is on the same side as it was before turning the same
rotation as it was before no biggie at all. This works flawlessly no fuss
no muss. The only thing you need to do is a little work to modify the
gear cover to get it to seal again like it did when it was a rear motor
plate.
This conversion became so popular at one time after I started selling it
for RC10's back in the early 80's that Mr. Moore made and sold trany
cases with the hole for the top shaft on the other side on his MIP
RC10/Tamiya trany kits so you did not have to plug the hole with servo
tape.
This still to this day amazes me how many people over think something
that is so basic & simple. I guess it is human nature to over think the
simple things in life.. 
Thanks, I will take the over thinking as a complement
as I am sure Paul and Chazz at the Xcamp will..
The difference between the current mid-motor offerings and those from the past is now we understand how to use things like the torque roll of the motor as a benefit instead of a hinderance. Ask anyone that has driven both a 3 gear MM car and a 4 gear MM car and they will tell you that the difference is night and day.Especially under accelleration.A 4 gear set-up is the ideal way to go if you plan on running dirt. For carpet you wont see the difference between the 2 as much,hence the old school conversions were generally used on carpet or oval.They were great in those circumstances just due to the mass of the car being more centrally located, which resulted in faster corner speeds. In an offroad setting they were hard to get the rear end to not be sketchy coming out of low speed corners under accelleration due to the motors torque roll wanting to fight weight transfer to the rear end.The 4 gear trannsmission was the key to helping with that issue, just as now we are trying to center the rotating mass of the motor to help apply that weight trannsfer in an equal manner instead of being offset in relation to the centerline of the chassis.It's another step forward.There is no need to re-visit that technology that was used by MIP,Tekin, and a few others as the achiles heel of that design has been found and corrected thanks to the guys at the X-camp.