[DonRotolo]

In Lunacy, we did measurably (but only slightly) increase tractive force by using a total of 12 wheels on a 6-wheel drivetrain.

It is absolutely true that increasing the contact area does not affect traction if the weight stays the same. But to explain our measurements we theorized that if any small area of the floor (or wheel) was allowing more slip (say, due to some dust on the floor) the larger contact area would allow for a smaller percentage of the available traction to be lost.

We made our decision based on empirical data, so not entirely anecdotal, but in hindsight we probably would use only 6 wheels in the same situation.