My presentation and a problem about tyres

I don’t recognise those as an option for any of our family of cars, if that is the case then you have a very nice set of after market wheels there, you are fortunate. Our cars have an unusual pitch circle diameter, based on an old standard & it is unusual to find after market wheels with that. However you might find that the hubs have been modified to accept the 100mm standard. If this is the case then there will be no end to your wheel options.
Which ever, we’ll done.
M

wow, Airportable!!!!!
... I am impressed; in order to control the effective PCD of my wheels I have dismounted the MG plaque on the front and I have measured tohe distance between opposite bolts: 100 millimeters... (more exactly 8/100... there are eight holes on the rim and only 4 bolts fixed on the hub)
As Frenchs say... chapeau!!!!

If there are eight possible bolt holes with only four used, you might have dual standard wheels.
I have commented on my odd bod wheels before, these are dual standard, one with our normal 95.25mm PCD & also 100mm.
I’m not sure whether these were around much a few years ago, if they were I hadn’t come across them until I bought my set. Yours set might be number two.
M

I drilled my hubs to 4x100 to get access to a huge range of alternative wheels.

I considered this but then questioned the sense for me. My fancy wheels will do me fine however for me it would be relatively straightforward; fit the spare, mark out the centres & carefully, carefully drill. Do use something to ensure the drill is square to the hub.
You will be able to fit the studs without removing the hub, unless you choose longer studs, although a judicious amount grinding might be “advantageous”.
M

Of course the proper way to drill the hubs is to hold them in the chuck of a dividing head mounted on a milling machine. once you've done your calculations and got it all clocked up then you will drill all the holes with the absolute precision required, especially important as you have quite a few holes to do and any, even the slightest error will cause you problems with runout and balance.
The trouble with this is the cost of the equipment is huge and then there is a lot of skill and knowledge needed to do it.
For me this is not a problem as I have the gear and have the trade background to do it, but for pretty well most of the rest of you, your better off leaving the old Black and Decker drill in it's box and taking the job to a proper machine shop. it is of course possible for some one with a bit less kit and and a high level of skill such as Airportable to do an acceptable job with great care. But for most blokes/blokettes this is a job best handballed to the pros. As this really is s safety issue, it can effect braking, handling and mechanical integrity.

I've even heard some people ask if they could slot the holes it the wheel to fit them to the hubs, the answer to this is NO! Doing this will only cause runout and balance problems as well as risking stud failure due to excessive load and for the fact that the wheel nuts probably won't ever stay tightened. Remember there is a lot happening with your wheel hubs when you are tootling up the road, there are great forces pulling and pushing in every possible direction simultaneously

No one with a modicum of mechanical knowledge would argue with that & if I were to do this it I would do as Cobber has recommended.
It was a mistake to make that comment as it trivialises the work involved & could have been seen as an invitation to the less skilled to rive at it with an inadequate drill shod with a blunt bit.
Besides there will be few dual standard wheels with which to use as a pattern.
Sorry folks, I should have thought that through.
M