pic: Installing a modular transmission


Adam in the process of installing a transmission gear module. The CIM in the foreground mounts over the transmission and 4 bolts lock it all together. Each installation takes less than 2 minutes and is accessible with ease.


I’ve been staring at these pictures for a while, and I have to say that I love the concept. (It makes me glad that we didn’t have a match against y’all at Palmetto that year.)

One question keeps bugging me, though: how do you keep those gears in the hand in the picture in place?

I am going to make a guess here to answer Billfred’s question (I am sorry if I am incorrect, perhaps someone from team 25 can answer this question better). I see standoffs, I am guessing the motors are bolted onto another plate which is bolted onto the standoffs after you guys install the “modular Transmission.” How much do your chassis weigh team 25?

Adding to that, I have always wondered how team 25 never lower their middle wheels and still turn very smoothly?

Are they wider than they are long? That would be how. Also, I believe those are the Skyway BeadLok wheels which are kind of like foam, and they perform quite nicely on carpet. They don’t have the “bite” of wedgetop or roughtop. I’m also guessing the width of them also gives a lower groundpressure preventing them from biting in so much.

Not all of their chassis are wider than longer. This past year it was longer than it was wider.

Good question Arefin. All I can tell you is team 25 has there transmissions down to a science I have seen them up close and personal many times. Quite possibly one of the most well designed robust drive systems in FIRST. They put a lot of Research and development into it every year too, because every year they have an improvement to it.


I would have to agree here. Team 25 has got building drivetrains down to a science as another person said =). The way they have their drivetrain setup makes them very quick and agile. I hand the students and mentors credit for building a setup like the one in the picture.

About how long does it take to replace a modular transmission like that?
Is it easily accessible or do you have to remove a significant amount of items to get to the transmission?

I think the answer to your first question would be about 5 minutes (if I am right about my assumption in my first post in this thread about how does that shaft stays in place). All they have to do is unscrew those two bolts and take the plate off in order to replace that “modular transmission.”

If you look at their robot from this previous year they had access everywhere. So to answer your second question, it was easily accessible.

… I think someone from team 25 needs to come and post in this thread and let us know the actual answer to all of our questions. =)

You have the correct idea Are fin. 5 to 10 minutes does sound about right because all we need to remove is 4 bolts. Some other things we do is try to keep our bolt and nut sizes as standard as possible so we have to work with less tools. There is a plate which holds the motor and attaches to the stand offs. There are a couple pictures on CD, I think. If not, I hope Mr. C can post some. And speaking of research and development, wait till you see what’s coming next year - something totally different which is under quality assurance testing right now. We’re very excited. Feel free to ask any more questions.

Our chassis typically weigh more than 70lbs. which does not leave much room for additional components but this year we scaled down by using different materials.

The reason we don’t need to lower our middle wheel is very simple. We make sure our machines have minimal parasitic loss from the motor to the wheels so every bit of torque gets to the wheel from motor(whatever is possible, that is). Our custom cut skyway wheels mesh well with the pattern on the carpet which is why it does not matter what the orientation of the robot is - long or wide.

Could you explain what you mean in more detail? Do you actually have some textured wheel that meshes with the fibers of the carpet, or mean something else? :confused:

We buy the Skyway wheels, then cut them down ourselves so that, as Bharat said, they mesh well with the carpet used on the playing field.

In this pic, you can see the wheels. They do not come shipped to us like they are when we put them on the robot.

Funny. I just found that image and was about to delete my post, but then saw that someone else had posted, and it happened to be the very same image I had seen about 10 seconds ago. :rolleyes:

Thank you for the explaining it to me, though.