Principal characteristics to search a Transmision to your Drivetrain?

Hi TEAMS! We are searching to change our 3 CIM Ball Shifter Transmission to some better (we would like to change to swerve Drivetrain but this season and probably next isn’t possible for time and money) and we expect to take advices to what we have to pay attention to select our drivetrain.
Which are the principal characteristics you have to look for when we are searching a Transimission to our drivetrain?
Thank you so much!

So assuming you have the funds. In very modern FRC shifting almost doesn’t exist for drive trains. With Neos and Falcon500s you have more than enough power to use a single speed for the entire match.

You should calculate the ratios of the gearboxes for your specific application before you purchase them, but the major thing to watch out for is the current that the motors pull at or near stall. It’s not recommended that you get into a pushing match but sizing the gearboxes so that your wheels slip before the breakers pop is ideal. You should look at how much current capacity the breakers have for the time that you think a pushing match could take place for the given specifications of your future robot. As the wheel size and number of motors will impact this dramatically.

There are several different pre-made spreadsheet/websites that can help you calculate your ratios. Many of them you can find on CD. A lot of them are similar for drive trains so just pick whichever you fancy.


If you haven’t yet, I always recommend doing the analysis of “sprint time from A->B”.

A->B will vary depending on the game, and how you choose to play a game. But, 99% of the time, FRC robots care about traversing a distance, stopping and doing a thing, traversing another distance, stopping and doing a thing, etc.

Picking gear ratios and motors which minimize the time needed to traverse the distances is, in my mind, a good universal design criteria.

If you’re looking for something more evergreen, you can survey the previous games for average sprint distances and outliers. I’d gander to say most games can be played with a quarter- or half-field average sprint distance.


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