Wheels for floor standing speakers

I had hospital cart casters on my workbench.  $100 for a pair 15 years ago, got two pair, two wheels each caster.I still have them - on my computer cart now.  Still work great.

Home Depot sells a variety of different size casters. I have bought some for use on some of my floor-standers.

I have Tekton Moab’s that I need to move a lot

I’m still trying to wrap my head around why speakers need to be moved "a lot". Especially those that weigh 135 lbs
As Jason said, there are lots of choices but small wheels may not be a whole lot easier than the gliders you already have. And larger ones will lift the speaker above its optimum placement. Whatever you get, the speakers need to be pushed from the bottom rather than upper part of the speaker. That may be all wifey needs to do to move them on the gliders. She is probably pushing from the upper portion.
If nothing else, get a couple hand carts and paint them to match the décor and then place them in back of the speakers in the ready position

Better be careful. 

Large caster wheels that are through bolted through the cabinets would work best i have a lot of large speakers and the biggest ones require that you have and use these types of accesories.