Which mecanum wheels to buy?

[Max Boord]

1523 used andymark mecanum wheels for the past 4 years and discovered a few differences between them:

6 inch wheels:

• smooth
• break rollers frequently
• easy to replace rollers
• more rollers

8 inch wheels

• less grip
• VERY loud
• easey to replace rollers
• rollers hardly ever break
• vibrate the whole robot

both feature unbreakable hubs
We have experimented with gear ratios, motor choice, and code as well.
2011: CIM drive 12.75:1 gear ratio on 8 inch wheels PID controlled
2012: CIM drive 8.45:1 gear ratio on 8 inch wheels PID controlled
2013: Mini-CIMs 8.45:1 gear ratio on 6 inch wheels PID at first event no PID at second- fifth
2014: Mini-CIMs 5.95:1 gear ratio on 6 inch wheels no PID loops

We are happy with how our 2014 drive is performing although it was probably not a good choice for this years game. All 4 drivetrains have never suffered an on field mechanical failure beyond carpet/ field tape getting caught in the wheels and the occasional roller damage.