Tank Drive Design, Including Bumpers

Our team rapidly went through these stages:

  • what drive base style?
  • not mecanum this year
  • hey we have spare tank treads!

And I agree that because of the 1 inch floor barrier, mecanum is not a viable option here and that a tank style drive is for the best. However, I want opinions on whether we should build the AndyMark Base Kit with 6 wheels (or 4 wheels) or do a tank with treads. Three things I worry about are agility, speed, and bumpers. How does one design bumpers for a tank, where the front treads are raised? Similar to this:

Shoot me with anything!

I think your other two considerations are more important but I would run a support beam out between the two runs of tread on each side.

Per the rules, bumpers don’t have to be parallel to the floor, so the front of your bumpers could be as high as possible while the back is still good protection for pushing matches which a tread system would be good at. You would just have to make sure you always push from the rear.
As for mounting them, this problem is similar to that of West Coast Drivetrains where most teams have bars extend from their frame to support bumpers

We did corner bumpers to not deal with the difference in height when we tried it in 2016 using Andymark’s Rhino Treads. They worked well enough, if you decide to do treads.

If the worry is the steel bars, swapping the wheels to Pneumatic may be the way to go. We tried treads in 2016, and have no plans to use it again. We were slow, we sucked at turning, and it was easy for bots to get around any defense we wanted to play.


Just stick to the KOP frame and how it comes. It’s designed such that when assembled per the instructions, it’ll work,


There is almost no reason to use tank treads this year. 6 inch wheels, like what come with the KOP chassis from andymark, will handle the bumps just fine.


Honestly, the 1 in barrier should not be the primary decision against mecanums. Last year, we tested crossing a 1in by 2in tubing with mecanums without any issues. If you are concerned about damaging the mecanums, you can consider yourself crossing the barrier just once or twice during a match (depends on robot design)
we are going for the KoP 6WD to make sure that we don’t get pushed inside oponents trench, which would result into a penalty for us.

If you are using the plastic VEX mecanums, it definitely should be. With the metal andymark ones you should be fine.

That being said, dont use mecanums. There is almost no benefit in this game for using mecanums, and there are loads of reasons not to.

This is a bit overkill for a 1inch obstacle, and will vastly impede your competitiveness. This year is about speed and agility. Even defensive robots will need to be fast and agile to be able to hit opponents in fairly tight windows of opportunity to avoid risking penalties .

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As someone who was on a team that used treads last year, I Strongly encourage you to stick to 6 wheel. The game doesn’t require it, so it’s just added complexity. There’s too many places it could fail compared to 6 wheel, which is perfectly fine this year. We were unable to play to our potential in multiple matches due to broken treads.

But if you are dead set on treads, make sure you add a place to tension them as they’ll stretch through the season

It’s also much harder to turn with treads than it is with wheels. As others have said, it’s way overkill for a 1" bump. Can’t go wrong with the KOP drive.

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