Gear ratio

[demonoid369]

Mods can move this to newbie section if it counts as that. But I was just wanting to double check on how pinion and spur gears effect speed and acceleration. For top end speed don't you want a big pinion and smaller spur or big pinion and bigger spur?

[SMR 510RR]

Its all about the ratio between the two gears.

Lets say that you had a 20t pinion and a 20t spur...For each motor revolution the spur gear would turn 1 time, for now lets pretend that our axles and trans had no gear reduction for simplicity. That would mean that for every time the motor traveled 360 then the tires would also travel 360.

Now if we changed out pinion out to a 10t then the motor would have to spin 2x for every one time the spur and the wheels would spin.

Now if we had a 40t spur and a 20t pinion then we still have the same ratio as a 10t pinion and a 20t spur so technically nothing has changed except for the size of our gears.

I think you can figure it out from there.

[demonoid369]

Well the question came up because I was at the lhs and I was trying to figure out how to get top end speed on my slash and from I've learned before and all that was that if I get a bigger pinion and a smaller spur, I will get a higher top speed but the guy kept saying I was wrong and that you need a bigger spur? I'm just trying to figure out which is right

[benoj]

more speed: bigger pinion/smaller spur
more torque: smaller pinion/larger spur

whoever said you need a larger spur clearly doesnt know much

[demonoid369]

Originally Posted by benoj

more speed: bigger pinion/smaller spur
more torque: smaller pinion/larger spur

whoever said you need a larger spur clearly doesnt know much

I freaking knew it!!!! Lol he's been pissing me off trying to get me to buy overly priced stuff and wrong info, thank you guys