We are currently in the process of re-designing our robot ready for our national championships. We have been hearing a lot about using pillow bearings to help a 4 wheel chassis get over the bump. We have looked into it and and now know what pillow bearings are, but we still have no idea how they could be of use; any help would be greatly appreciated!
Since most teams use 4" wheels (or 2" radius), and the bump is 2", the bottom of the c-channel would scrape the bump. However, when you use pillow bearings on the bottom of the c-channel, you get the extra clearance needed from the ground to not touch the bump.
I personally don’t like to use the pillow blocks underneath as it makes mounting motors a bit trickier, and isn’t as strong. What I, and many other teams, did was just mount the wheels on a short piece of C Channel underneath the main frame. I can put a picture later.
Just make sure that nothing underneath it goes beyond the circumference of the wheels.
Mounting motors on pillow blocked wheels is really easy. You just rotate them 90 degrees. Here’s a photo of my X-Drive earlier in the season where I did exactly that. There were problems with that X-Drive I won’t get into right now, but the idea is fine on anything running Tank or Mecanums. We have them on all 3 of our robots right now.