gearing for xxx-t

[lds12]

I have a bone stock old xxx-t with 2.43:1 internal and an 88t spur. What size pinion would be best for a 9x2 motor?

[TimisTim]

I would start with something like a 16t pinion. Take a temp reading on the motor and esc every now and then and drop a tooth if it is to hot.

[Graystar]

I would start with something like a 16t pinion. Take a temp reading on the motor and esc every now and then and drop a tooth if it is to hot.

That's way too high.

You really should send Losi an email and ask them for a recommendation. I personally would start with a 12T, but starting with a 13T should be okay too. The answer is going to be between 12T and 14T. 15T and above with burn out your motor.

www.teamlosi.com

[TimisTim]

I guess it all depends on how large of a track you are on. I used to run a 12 turn on a 16 tooth pinion on a very tight track with a stock green spur gear which I believe is an 86 or 88. It did very good in 5-8 minute races but would require a cool down after the run. I just did the "if you can hold your finger on it for 5 seconds test."

The rule of thumb is stock motors (I think 20 turn) start at 22t and for every turn you lose you drop a tooth. So you have a 9 turn which would put you at an 11t pinion which is a little small in my opinion so as Gray said stick to the 13-14 range.

[Graystar]

I used to run a 12 turn on a 16 tooth pinionYes, that's exactly what Losi recommends. Their recommendations follow a fairly simple pattern...drop a tooth per wind. So they recommend 13W/17T, 12W/16T, and 11W/15T. Unfortunately they don't go below that so you have to guess...10W/14T and 9W/13T. That's where I came up with the 13T.

Just keep in mind that you usually have to stay within 1 tooth of what the recommended size is. That why I say the range is 12T-14T.

Drivers don't realize how HUGE a change of 1 tooth is. A change from 12T to 13T increases the load on the motor by over 8%. It doesn't sound like a lot, but it is a lot to these small motors. Change the pinion by 2 teeth and that about a 15% increase in load. That's why the motors burn up. 15% is way too much additional load.