[EricH]

Originally Posted by the man

We are using the 8 inch. The rollers are incredibly grippy on the bridge, I fore see no issues. More testing will likely occur tomorrow. I will post any thing else we find out about them on here tomorrow. Why would they have a problem with the bump?

8" wheels, 4" bump, your axle hits smack-dab on the top of the bump. That makes it a little bit tricky to get up and over; I'd put a set of skid plates to knock the bump under the axle to help the robot get over the barrier.