The whole project kinda got put on ice when I realised that almost all my other furniture has castor wheels, which makes them barely an inconvenience to move. My set of drawers is the only thing that doesn't and even minor adjustments are a struggle. The server cabinets I bought didn't come with them and I very quickly decided to buy and install them, so it's likely in my best interest to integrate them into the bed frame design.

After quite a bit of searching and comparing websites, this one was the lowest cost for 4 wheels, priced at £40 inclusive of VAT and shipping. Whilst being the cheapest, they also have the highest per-wheel loading capacity of 100kg, where the lowest I've seen are 70kg. I've never applied the brakes on any wheeled furniture so I will just get 4 plain wheels.

Scaffolding Supplies LTD offers free shipping over £100 excl VAT, so in theory I can split the key clamps order between The Metal Store and them to get free shipping at both and save £12 in delivery fees for these wheels.

Notable Mention

Looking at reviews and the description, this one was designed to simplify the installation down to tightening a single allen key grubscrew, for a convenience fee. Thus I assume that, for the first type, the wheel has to be unscrewed, then the expander has to be screwed into the tube, and finally the wheel rescrewed.