I have also heard that when those larger wheels get loose with wear over time, it tends to be a disaster compared to smaller ones.
Your advice is good...I agree that buying a commercial quality 21", if you one can allocate the money to it, is a wise move. Even at $800 to 1,000, a non-self-propelled commercial 21" Honda or Toro costs far less than a consumer grade sit-down mower...which doesn't make sense on a yard smaller than a certain size anyway. Or at the very least, try to buy a higher-end consumer grade model, like the top-end Honda HRX models or Toro Super Recyclers....which cost $500 to 700.
Another advantage of the higher-end models is that they tend to have higher top-cut heights. The Toro commercial 21" goes up to 4.5 inches HOC! I'd love to get one of these someday: https://www.toro.com/en/professional-co ... push-22289
That said, I was hoping manufactures would reverse this trend of making their lower-cost mowers with the larger rear wheels...it just seems like another thing to break down.
Still, any first-hand user experience in this thread, for high-wheel push mowers is still welcome....if anyone uses one.
Front: Northern mix - mostly TTTF, KBG, TTPR. Back: Firecracker and Bullseye TTTF with America, Rugby 2, Bewitched KBG. Upper Side: Mostly TTPR, KBG. Lower Side: similar to front. Low-input: TF/FF, KBG, PR. Always seeding somewhere or fighting Triv.