andy85

I'm reading the manual for an LRP 3.5 brushless motor and its saying for a large track use the ratio of 8.9:1. Question is, what do these number mean? Is it the number of teeths on the spur or on the pinion or what? Inputs would be much appreciated.

Blisster

iTrader: (5)

It is the number of teeth on the spur gear divided by the number of the teeth on the pinion gear multiplied by the drive ratio of your cars transmission.

so for my car, a FT TC4 that has a transmission ratio of 2.5 a 93 tooth spur gear and a 46 tooth pinion it would be:

(93 / 46)*2.5=5.05

http://gearchart.com/ is your friend! You may need to refer to your car's manual to figure out the tranny ratio for your car.

andy85

You're a champ!!! Now i know how it works =]. Thanks million

Marcos.J

iTrader: (239)

the larger the number = more rip out of the line
the lower the number= more top end (but more heat and less run time)

BayArea101

whats the "P" on a pinion gear? 48 or 64? what does it mean?

Also blisster, isn't 46T pinion gear a kinda lot of teeth? why do they same you should run 6-7 teeth above the turn of the motor but some ppl have a super high number of teeth?

Blisster

iTrader: (5)

the P stands for Pitch (the number of teeth per something) 42P gears have less teeth than 64P gears. I think 42P is standard in most RTR type kits, with 64P being a bit more adjusstable.

:edit:
Bayarea101 (woohoo bay area in the house!)
46T seems like a lot of teeth for a pinion gear, but remember, I am running 64P gears, so my spur is 88 teeth (just dropped from a 93) I'm still trying to find the sweet spot for my BL system, but alot of guys at the tracks I've been running at (Marin RC and NorCal) are gearing their brushless set-ups in the high to mid 4's for stock class.

BayArea101

In someone wanted 2 post the drive ratios of all the major electric 1/10 buggies it would make a happy boy...