After 4 x heavy duty rubber wheels with vertical stoppers from the rack or similar in Auckland
Got 4 from decomissioned rack (perfect) and used them in the custom made dolly. Vertical stoppers are essential as the dolly does not move at all when those are engaged.
Wheels from Bunnings are of no good - when you use stoppers on those - they still rotate.
So, looking to change wheels on another dolly - if you are throwing away old rack - please let me know.. I will come and take the wheels off..