To avoid any confusion about wheel sizes, etc, I should point out that our gun has custom made mud-guards so as to meet highway code requirements for a trailer... we used the NATO M series lights as they are nice and bright while still looking nice and martial. The mud-guards are easily removed to return the gun to its original looks when and if needed.
I have the original wheels and tyres stored indoors with 10 pounds of air in them should we need to put them back on for special displays. The current wheels are 16 inch Chevy truck rims with custom machined centres and radial retreads which allow me to tow the gun at modern speeds on the highway.
The Ontario Highway traffic act defines towed artillery as "devices" which require all applicable lights, etc but do not need to be licence plated as the load is permanent and not removeable. The Bofors is plated as I made the error of explaining to the lady at the motor vehicle licencing bureau that it has seats...
If it has seats its a trailer and required the plate! Lord preserve us from the 'gummint' bureaucrats!
Cheers, Mike