# pic: Flipped Transmission By SteamPunk #1577

Steampunk 1577 has recently been working on a flipped transmission for 2 cim motors in 1:4.66 ratio.
The transmission is made of 3* 5mm (~0.2") aluminum plates, 2* 44t 20dp gears, 2* 12t 20dp gear (for cim) and a 56t 20dp gear.
It’s designed in two levels - the first level decreases the speed (1:4.66) and the second level passes the rotation to the wheels’ axis.

While designing this we used this formula in order to calculate the center distances:
C = (N1/DP + N2/DP)/2
Nx = number of teeth on gear x
DP = diametral pitch

We wondered whether should be any extras added to the result of the above formula?

Would like to get your opinion,
Amit Shavit, SteamPunk #1577, Israel.

What was the design decision(s) behind flipping the transmission (CIMs facing out towards the wheel)?

Are there any designs you considered that would achieve the same reduction in a smaller footprint and without the flipped cims?

The usual reason for using a flipped-CIM gearbox is to maximize the space inside the chassis while keeping the gearbox in the center wheels. With a normal transmission, the motors take up a lot of room in the middle of the chassis that could otherwise be taken up by robot mechanisms or game pieces.

Do you have any ideas that would give the same space inside the chassis in a smaller space without flipping the motors? I’d be very happy to hear them.

Exactly what’s Ari said.
You can go also with something like RAW Box style, but worm boxes are much less efficient.

No, I didnt have a specific alternative in mind aside from some interesting vertical motor orientations. I was just curious about the choices that went into it, since it seems like its very tightly packed - I was initally worried about the wheel burning through the cims

I like the work, gives you more space in the center which in many games is critical. curious to see more iterations.