Like many of you, I didn't need locking replacement wheels. I wanted something higher quality than the stock wheels, but NOT larger diameter. Not a lot of choices out there. And by that I mean I've never found any until last week.
Found a pair at Lowe's with hard rubber wheels:
http://www.lowes.com/pd_66955-255-4384999NN_0__?productId=3037441&Ntt=waxman+2-in&pl=1¤tURL=%3FNtt%3Dwaxman%2B2-in&facetInfo=Pulled out my jack stand, propped up the grill and pulled down hard (not "fast" but with determination ...) on the wheels and they popped out.
Removed the sleeve with a screwdriver.
Here's a rough size comparison (ignore the plastic doohickey propping up the old wheel)
Inserting the new wheels was done in about 3 stages, the initial push which gets the stem barely in, then the rest goes in fairly easily afterwards. Stage three is to take the grill off the jack stands ... the wheels will need to go in that last 1/4" ... push down on the grill's handles (er, plastic table for '05-newer ...) and they'll pop in. So yeah, I reused the original frame inserts. YMMV on that.
Rolls like a dream, now!