I exclusively run foam wheels in my ant-weight robots. Here are a few things I've tried:

  1. Foam wheels with adhesive grip tape - This works okay on wood floors, but it can be a bit heavy and my bots don't have enough mass for it to get really good grip (at least with the 60 grit tape I tried).
  2. Foam wheels with cast Vytaflex 30a tire - For these, I laser cut foam wheels with a retention pattern, then made a mold and cast them in Vytaflex. This gave me a super grippy wheel that was still light and compliant. However, if I didn't get the retention pattern right, the rubber could peel off. It was also a fair bit of work and the Vytaflex took about 24 hours to cure.
  3. Foam wheels with latex - This is my current solution. It's light, grippy, cheap, and easy. Some people put a layer of rubber cement down first and then coat it with latex, but I don't. Instead, I scuff the foam with a wire brush or sandpaper to create a rough surface, clean off the dust, and give it a quick wipe with alcohol. Then, I apply several light coats of latex, making sure to work it into the roughened surface. With this process, I haven't had any problems with the latex peeling up, and it's easy, cheap, and fast to do. It doesn't require any special tools or processes either.  This is the latex I've used. It's sold for body painting, so you know if you feel uncomfortable ordering it, it's the right stuff.