Hi VM, with a new tyre the rubber is soft and you use a screwdriver to lift out the rubber and pop the hubcap in.
But our wheels are 60 yrs old and are hard and cracking......
I got mine in, by spraying the rubber with WD40 and using a wooden hammer to tap them in.... worked...
Get some pics of the work of art.
cheers
speedy


........................Keep your blades sharp......................