4" vs. 6" vs. 8" wheels. Advantages?

[548swimmer]

Originally Posted by Chris is me

Anecdotal evidence does NOT equal data. You're comparing apples to oranges half the time, and non-equal test cases ("oh that team had treads and could push anyone around!") are useless.

As of right now I have empirical proof that surface area affects static friction. A video of this proof will be uploaded to YouTube within the week, but for now you just have to take my word for it.

[Chris is me]

Originally Posted by 548swimmer

As of right now I have empirical proof that surface area affects static friction. A video of this proof will be uploaded to YouTube within the week, but for now you just have to take my word for it.

The double wide strip weighed twice as much - that's pretty important!

[EricH]

Originally Posted by Chris is me

The double wide strip weighed twice as much - that's pretty important!

But, with that noted, it shouldn't be terribly hard to rerun the test with a few fishing weights duct-taped on top of the single-wide strip so the strips are equal within a few grams or so. Then, put up both videos.

[548swimmer]

Originally Posted by Chris is me

The double wide strip weighed twice as much - that's pretty important!

Actually, it didn't because I used two segments of 2x4 for the weight on the double wide strip and stacked two 2x4 segments of the same length for the weight on the single wide tread. The only weight difference is the weight of 3.5"x6" of rougtop tread and 3.5" of two-inch aluminum angle iron, the total of which could hardly combine to cause an additional 2N of frictional force.

This would be one of those "if you don't know, don't state something as fact" moments.

EDIT:
I had one of our animators edit the video, and I just got it sent to my email unfortunately, it's a download link so I am unable to view it on my iPod . However, I trust he did a good job and so here's the link: http://dl.dropbox.com/u/4749895/Comp.mp4

[Chris is me]

If that's 1/4" thick AL, that's a third of a pound of material. Assuming those 2x4s weigh about 3 pounds and your traction material is 1.0 CoF (rough guesses here), the third of a pound would indeed make the difference.

That being said, I think it's VERY cool that you tested that with demonstrable result. If doubling thickness does increases your traction by 11%, that could be something.