The first question to ask is: What do you want these wheels for?
"Racing" is not a usual descriptor for most FRC wheels. Usually traction and maneuverability at low to medium speeds are more important than maintaining control at high speeds, or than raw acceleration from a stop. Also, you must consider what surface(s), irregularities, and slope(s) you may encounter. Most teams have used nearly as many different types of wheels in competition as they have played seasons. For example, 3946 has used:
- 2012 Rebound Rumble: 6 @ 6" Wedgetop (planned to play defense)
- 2013 Ultimate Ascent: 2 @ 6" solid rubber and 2 @ 6" omnis
- 2014 Aerial Assist: 4 @ 6" Mecanum
- 2015 Recycle Rush: 5 @ 4" DuraOmni (H-drive)
In none of these cases was "racing" a top goal. If you do want to race, you still need to consider the surface and the turns in the track; Drag racing, Formula 1, and NASCAR all use very different tires for pretty obvious reasons.