This will be a repeat for SMC members, but I just got a set of Zambus casters underneath my MM16 this afternoon, and man are they sweet. After ditching the factory Johnson Bar setup, I went with a Delta mobile base for about a year (see this thread http://www.sawmillcreek.org/showthread.php?t=10507 ). It worked way better than the Johnson bar from a stability standpoint but I still didnt think it rolled on my somewhat uneven shop floor very smoothly. It would occasionally hang up in spots. Between posts on SMC and on the MM Users Group forum, I'd been reading a lot of glowing posts on the Zambus casters and decided to go fer it. They showed up a couple of days ago and got them installed today. The hardest part by far was getting the saw off the Delta base. Got some help from a neighbor to get the MM16 up on blocks and slid off the Delta. After that it was a one man show. Removing the blocks was easy after turning the caster adjusters all the way up. In addition to the smaller footprint (no surrounding mobile base) it also raised the table higher, which is nice. From the floor to the bottom of the MM16, it's now 3.5" and will go maybe another inch when the footpads are adjusted down so it's stationary. The Delta had the saw raised off the floor about 3/4" or a bit more. So I'll take the midpoint of the adjusters and say I gained 3" on the table height. I'm 6'3" so the height gain is just icing on the cake. With the footpads lowered, the saw aint going nowhere. It's as solid as a rock. But rolling the saw is incredibly smooth, even on my floor. Turns on a dime too, as all 4 wheels pivot rather than just the single pivot that the Johnson Bar or Delta base had.
I got the same one's Jeff Wright recommended on the MM User Group - AC300S. The total with shipping was $151.35. The Delta 50-296 mobile base I had it on is $90 at Amazon. Just MHO, but the Zambus are worth the difference. I had a little problem on two of the casters due to powdercoat on the MM16 threaded holes.