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Idler Sprocket Washer Size for Zumo and 30T track set

Hi I am trying to build a robot that needs tracks, and I have settled on the 30T track set or #3033. I have a simple question: what is the size of the washers that are included in this set? The simplicity of this question may cause you to think that I have not done my research, but I can assure that for the majority of the last few days I have been desperately trying to find the size of the washers so I can model them in CAD. I have reread their product descriptions numerous times, surfed this forum and google for hours, and finally tried to use the provided CAD files to my advantage. None of those methods work.

This is not the same track set that was included in the Zumo kit but the only difference is that it has more teeth compared to the 22T tracks included with the zumo. If any of you zumo owners could take 30 seconds out of your day and quickly measure the washer that was used to mount the idler sprocket I would really appreciate it! If it isn’t too much trouble, it would really help me if you could provide the inner diameter, outer diameter, and thickness or the size of the washer.

I honestly think that this should have been mentioned in the product description so that others don’t have to go through the same hassle I have been through simply to determine the dimensions of a washer. Please let me know if this was included and I missed it.

Hello, rocketRobotics.

Sorry for the inconvenience. The washers that come with that kit are #4 stainless steel washers. The dimensions are as follows:

Outer diameter: 0.312"
Inner diameter: 0.125"
Thickness: 0.04" (max)

I have passed on your suggestion to add those details to the product’s documentation.


Thank you so much!