pic: Team 701's Custom Single Speed Drive Transmission

Got our pieces painted for the transmission and this is how it looks together.


Couple of questions: what’s your reduction ratio, and do you have room for alternate gear sets to adjust it upward? Will a larger diameter wheel fit under the motors?

The reduction is 4.91:1 if I recall correctly. We have some room to change the pinions to slow it down if needed but with the testing we’ve done, the acceleration is good and we aren’t browning out. We’ve also tested the 4 inch wheels on the platform, the bump and on our 2007 ramps and we’ve had no issues with getting beached on any of them. The 4 inch wheels are here to stay but yes a bigger wheel can fit under the motors.

I’m curious, are you running 6 or 8 wheels this season and how long is your wheel base? My team messed around with using 4" but decided with 6" due to it being very close on ground clearance, too close for comfort.

We’re running 6 wheel with an 1/8th inch center drop. I’ll have to check the length of the wheel base when I have access to the cad later today. Note we’re running a brain electrical pan so we won’t have the added thickness of a belly pan.

Brain electrical pan? I’m not familiar with that. Could you explain, please?

BTW, still admiring your team. Hoping to play with you again some day; 2013 is a distant memory at this point.

It’s an inverted belly pan similar to what 1678 ran last season. Pan mounts to top of the frame and the electronics mount from the bottom to the pan. I wasn’t on the team during 2013, but from everything I’ve heard it was an amazing event. The thing limiting us from going back is it’s a week 4 and our home regional is always week 4. If one of em changes you can expect to see 701 back at Colorado.

Driving up directly onto the corner of the platform is the thing that scares me the most about this game. I trust your team and your testing methods, so I’m not questioning your decision to run 4" wheels, or the inverted belly pan. But I will say that our testing made us move most of our electronics high, made us eliminate the bottom-attached pan and move our cross-frame up, and made us choose 6" wheels. I’ll be watching y’all to see how you’ve proved us wrong.

Looks good guys!

This. I’d like to see the full design. I don’t see how it clears in every orientation with 4" wheels.

I agree, if they pull it off and make it work, I may have to switch to 4" wheels during season. My team is raising our belly pan 1/2" off the bottom of our rails, plus using 6" wheels, and we are still nervous.

We’ve tested a pretty standard 4" WCD, with the bellypan on top of the frame. The only orientation that gave us any trouble was the corner of course, but as long as we didn’t try to go up from a dead stop, it was no problem.

Does that include your bumpers? We are designing with 6" wheels WCD so we will not run into the step or have our bumpers drag on the ground when going up the corner of the step. Maybe it works in your case since you are putting the belly pan on top of the frame instead of the bottom.

Kudos for you to do the hard work to actually design and build a custom transmission.

It looks like two full-CIMs and you said only one speed.

Why is this better than the toughbox mini?

Lighter? To teach the kids more?

These are two mini CIMs and the toughbox mini is not as compact in design. The output shaft of the toughbox mini does not go on the same side as the motors. The custom design allows the motors to sit on top of the chassis perimiter instead of having to be inside it.