[FTC]: FTC Wheels

Other FIRST Tech Challenge
1

Hi Everyone! I’m a first-time robotics coach and this is my 2nd post here. Many thanks for all the valuable information!

My team got our KOP two weeks ago so we’re way behind. My team has no experienced members so we’re all rookies. We are planning to build a simple chassis and drive: two driven wheels and two omni wheels. We currently have four 3" Tetrix wheels, four 4" Tetrix wheels, and two 3" Tetrix Omni Wheels.

In a matter of minutes the team was divided over 4" vs 3", front versus back wheel drive, and single vs dual Omni wheels. My first inclination was to guide them toward using two 3" Tetrix drive wheels and two 3" Tetrix Omni wheels and get on with the rest of the robot ASAP (with total cost $0).

Then I get online this weekend and see all kinds of discussions about clearance issues, sticky lateral movement for single Omni wheel… Poor traction of the Tetrix wheels on the foam floor… I can get two 4" Tetrix Dualie Omni kits ($21 per kit) or two more 3" Omnis ($17 each). And then I start coveting some 4" AndyMark HiGrip drive wheels ($9 each) and maybe their 4" Dualie Omnis ($39 each).

Being a rookie leading rookies I am at a loss if I should order more wheels (and if so, which ones) or if I should quit worrying about the wheels and worry about ordering something else. Like servos. We are seriously behind. :frowning:

Any comments or suggestions are appreciated.

2

If you’re not powering the omni wheels its not critical they match in dimension to the ones being driven as they are basically acting as a caster wheel. So if your budget (and design) is only going with 2wd I would just get a couple more 3" wheels and call it done.

I would also say if you look at the teams who are most succesful they are using 4wd or more, I find them to be easier to control and provide better pushing vs 2wd. But that is for another debate.

I have seen the AndyMark traction wheels used here and they work extremely well, especially compared to the tetrix wheels in raw grip.

3