pic: Why aren't omni wheels like this used?

[Nick Lawrence]

The DuraOmni wheel rollers are designed with a 4" wheel in mind. It is smooth rolling and the overlapping rollers create a true 4" diameter circle when viewed concentric to it's center bore. The rollers on AndyMark older omni wheel offerings such as the 4" Dualie Plastic Omni Wheel were originally designed for an 8" wheel, and were used on other wheels to save costs. They do roll fairly well in 'dualie' setups, but are not as smooth rolling as a DuraOmni. I've attached a photo comparison of both.

http://i.imgur.com/UehYLgD.jpg

Another reason why omni wheels like the one you posted aren't used in FRC is due to the requirement of more than one mold for the rollers. Molds are expensive, and many FRC teams are looking for high quality inexpensive components for their robots.

- Nick