Help ordering WCP DS WCD 3 CIM Gearboxes

[HenBaland]

Hello all,
Our team (2175) decided that we wanted to go with the WCP DS 3 CIM West Coast Drive configuration for our drive train gearboxes this year:
https://www.vexrobotics.com/wcp-ds.html
Our question lies in what different Spreads mean for the 2 output speeds. Is a lower spread less of a gap in between high and low gear? How would we find out what that high and low gear output speed would be?

Thanks in advance for your help.
Sincerely,
Ben Haland
FRC 2175, The Fighting Calculators

[AriMB]

Spread refers to the ratio between the two gear ratios in the gearbox. So if a theoretical gearbox has ratios of 4:1 and 12:1, it would have a spread of 3x.

To figure out the output speeds of a gearbox you need to know the actual ratios for low and high gear, not just the gearbox spread. You can do that for each speed by dividing the product of all of the driven gears in the train by the product of all of the driving gears. Once you know those ratios, you can use a number of calculators like mine or JVN’s to figure out the free speeds for each.

[hen_baland]

Thank you! I can’t seem to find what other gears are in the gearbox other than the one for each gear. Does anyone know what other gears are in these gearboxes so we can find our two gear speeds?

-Ben

[AriMB]

If you scroll down to the bottom of the page you’ll see a picture with all of the options for the various spreads and pinions

[hen_baland]

I see that now - thank you so much!