As far as I can see there is no difference between the two chainsaw files show. Both are 5/32" or .1526" (3.87604mm) the #19 drill is .166" (or 4.2164mm)....so the chainsaw files are smaller by .010" or so. The #19 drill bit cleaned out more plastic than I would have thought. I tried to put the pins in after having run the drill in forward only...they went through but had a few snags. Once I ran the drill backwards....they fell right through.

I agree. You spend $550 on an item and you have to modify it out of the box ? It's 2017 and they can't have a perfect fit for the hinge pins right out of the factory?

I was using a 17t pinion on my .3 and dropped to a 15t on my .4 and my temps were a bit out of control 160deg with a heatsink and a fan on it.
My motor is a T8i 1950kv. Hoping I can fit a 14t, it should bring the FDR back to the same as my .3 was.
This got me to thinking, what is the benefit of the new ring/pinion ratio if I am gearing it to the same FDR anyway? thanks.

Edit: Also I noticed the new body fits a lot tighter around the front and back. so there is less air getting into and out of the car, this may be a big factor in my motor temps.

I agree, but most parts that are molded shift as they cool so there will be binding. Hand fitting parts on the initial build is just part of the challenge of building a great handling rig. I enjoy it most of the time as long as the entire kit doesn't need an X-Acto Knife trim or file job.

14T FDR = 10.46571428571429

Joe have you put your .4 on a scale yet? I'd vent the body and see if you can shed a few grams if possible.

The drill bit info would be great to have on the first page.

I went to Menards on my lunch break and got a 5/32 chainsaw file. Buzzed it through the arm, and it was still tight. So I buzzed it with a little pressure, up, down, left, right and it was perfect. Then cleaned it out with the reamer. Worked like a charm. Thanks for the suggestion.

As they say, there is more than 1 way to skin a cat.

Either way, glad that you got it just the way you want it.

No I have not weighed the new one yet. I will have to do that.

I had good results with the #19 bit but I can see how the chainsaw files might make for a cleaner hole since it is essentially smoothing out the barrel as it works.

Whereas It took a little finesse to get a clean hole with the #19 bit

Also, try your old body on the new kit, to eliminate that entirely from the heat equation. You will need to open the front of the old body up a little for the new ackerman though. I'm also going to be trying to fit a 14t, but for my 2100kv SMC motor.

As for the reason, this all spins the center shaft less quickly, which means the rotating mass down the center is less of a drag on the motor, and therefor more efficient if the rest of the system is the same in efficiency as before.

very curious to see how the temp thing goes with these changes, especially with people running on smaller tracks relative to Kv on a motor.

It may be we are going to want to start sourcing 1700kv motors here ...

Hello Cain,
To obtain the highest durability we chose 100% nylon on the arms and unfortunately the shrink rate with this material is somewhat high. We worked with manufacturing to try to eliminate the need for reaming and could not come up with a solution.

Glass filled arms (that many other manufacturers use) require less reaming but are not as durable. Hopefully, the increased durability outweighs the need to ream the arms.

I personally use the chainsaw file with a drill, others like the hudy reamer or the #19 drill bit. It's mostly personal preference. 5/32 chainsaw file is 3.97mm and slightly smaller than the 4.0mm hinge pin. Recommend moving the arm around a little while using the file with a drill. This will help enlarge the hinge pin hole slightly. Goal is to enlarge the hole just enough for the hinge pin to fall through by gravity (and maybe a slight tap) alone. Reaming it too far will cause excessive slop in the suspension.

Hello Jmcelroy42,
I might have missed it but what are the dimensions of the track you run on? 17t on the .3 and 15 on the .4 is quite low gearing. Meaning it should be running this gearing on a very small track. If you are running on a larger track, we recommend going to a larger pinion as 4 pole motors can generate excessive heat if the RPMs are too high. We pretty much run 16 or 17 on all tracks with a T8 1900.

Also, a T8i might not be the best motor if you are running into heat issues. you might need to be using a T8.

Another issue could be the motor is old. Over time the magnets lose their strength causing you to push the motor harder, generating more heat.

165 degrees F is not excessively hot and you should be fine as long as temps do not go over 200 too regularly. I've seen Tekins go up to 300 and still be fine.