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spur gear

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andrewn5998

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  1. Bashing
I was out playing the other day and hit a telephone pole at full spead and broke my front bulk head and stripped the teeth off my spur gear. So I'm ordering a new bulk head and spur gear and was wondering what teeth to get i seen 38, 40, and 45, which one would be better for low end power and what is stock on a revo. My reverse gear is also messed up what is reguired to fix it. i know alot do the forward only kit but i like to keep reverse.
 
The higher the tooth count on the spur gear the lower your top speed will be, but you will have more low end torque.
 
But doesn't the cb gear have something to do with it? Like running a 17t cb with a 40t gear would give you a higher ratio, and therefore more speed?
 
Yes increasing teeth on the cluthc bell will increase top speed changing either gear will change your gear ratio.
 
You have to figure out what you have first. If you want faster than what you have, decrease spur or increase bell, or both. If you want more low end torque, increase the spur or decrease the bell, or both.

Depending on the engine, terrain and tires/wheels, make sure you gear accordingly to power if you want it to be faster. If your engine struggles now to get to top speed, then gearing taller will just make it struggle more and may actually go slower. Also, taller gearing is harder on clutch shoes and bearings due to the increased slippage to get it up to speed causing extra heat.
 
right now i have 15/38, if i go 14/40 that should give me lowend right? and how much would i loose off top end?
 
factory tires/rims, i just installed a new 3.3 motor used to be a 2.5
 
I wouldn't go lower than a 15/40 or a 14/38, you'll be disappointed. Yes it will have plenty of torque, but I can get a 3.3 revo to wheelie with a 15/36 combo no problem.
 
I think it's 15/36. I can't find a 2.5r on Traxxas' website, but the 3.3 revo is a 15/38 factory
 
The 2.5R parts explosion I have lists the it running 15/38 as well. I ran 15/40 when I ran a 2.5R in mine a few years back. I think I ran 15/38 in it when I ran the OS18TM, but that engine had power to spare. Wheelies all over the place. My problem was where I had to run it was very short, so taller gearing just meant more clutch burning.

Man... I should have kept that thing. It had some parts on it I wish I had now! RPM arms, fantom pipe, OS18TM header, RPM axle carriers... could really use that stuff now that I have one again... well, a slayer, but I have all intentions of making it a revo.

Lesson learned. If you liked it once, you will like it again later, so don't get rid of it... no matter how much your wife complains about all the crap you keep!
 

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