How many gears in a tranny is best?

[Duuuuuuuude]

Some of you may have seen my thread from a couple weeks ago when I was building my own trans out of some Maxx parts. It was a good effort for a first timer, but I need to redesign it to make it more efficient. What I'd like to know is; what are the pro's and con's between two gear and three gear setups?

Any input is greatly appreciated. Thanks!

[Narly1]

Interesting question. I imagine there are quite a few design trade-offs that come into play when designing a R/C car transmission. Here are a few of the factors I can think of:

- using multiple smaller tooth-count gears to keep rotating mass lower

- gear wear as a function of tooth count and pitch

- drag as a function of gear count caused by bearing drag and tooth mesh drag

- base gear ratio required

Looks to me like a simple 3-gear design is the defacto standard in most manufacturer's 1/10 scale trannys. This must be for a good reason, so you might want to avoid reinventing the wheel so to speak.......

Narly1

[Duuuuuuuude]

lol...I didn't mean "redesign" like I had a revolutionary vision, I meant it like "I need to build a better one than the POS I built the first time". Just trying to make it more compact than the E-Maxx trans using the minimal amount of parts at hand, but a bit more thought out than the one I'm using now.

The two gear setup would be much more compact, but like you said, most use three so there has to be a reason why. Maybe its simply to reverse direction or to keep the shafts far enough apart to run a big spur without interference.