6 Wheel Drive vs. 8 Wheel Drive

[Cory]

Originally Posted by Gray Adams

If you don't mind, why did you guys use a 6wd in 2011 after having used 8wd in 2010?

We only used 8WD in 2010 to allow us to cross the bump. We would not have used it this year if there had not been another obstacle to traverse.

It adds a non-trivial amount of work for us to make more wheels, bearing housings, much more involved side rails (something like 8 operations each this year, due to the size of our mill), as well as a third unique shaft for our sponsor to run. There is also a weight penalty.

[jwfoss]

This year FRC2168 went with an 8wd, over last years 6wd. Below are some of the factors played into this final choice:

• We wanted to ability to cross the barrier, without an active mechanism, with the smallest wheels possible without the chance of high centering. (resulted in 5" Colson Performa wheels, with a wedge leading edge on the chassis)
• The center to center distance between wheels was all equal, and calculated to ensure that high centering was not possible
• Our base driver commented on the "tippyness" of our 6WD last year and with shooting, we determined that being as stable (and repeatable) as possible was important
• With a 6WD we would have been able to hang more of the bridge, so to counter that we made the entire chassis shorter (only 34" long)

I will say that the drivers and the rest of the team favored the 8WD and we will likely be refining it as we move forward.

You can read some more about it and see some pictures here: FRC2168 - Behind the Design - Drivetrain

[dricks]

Team 704 used 8 wheels this year mainly because it was the students design. Our 8 wheel drive was a bit different then most. We used 8" wheels in the front and back and 6" wheels for the middle four. The Front and back wheels were raised .5" Making there center 4.5". this allowed us to cross the center "Hump" easily. The wheels were geared to run the same speed. The four center wheels gave good stability.