Interesting point, but as I learnt on a certain flat six German car I have in the fleet, if you want decent ride quality / good handling, there comes a point where the size of the rim becomes purely cosmetic, and the loss of flex in the side wall makes the ride too harsh...
And as I live off a road with 6 large speed humps in the first 150yards, I want some sidewall flex!! (Must be getting old....)
I think you're right and it's not just the ride comfort - tramlining can be a problem and steering feel can suffer. I run 45-profile tyres on my Uno (15" rims) and of course they look cool, but the steering feel and grip levels on a track are better on 13" wheels, it made five seconds difference in a 1:20 lap
plus, the 60-profile tyres break away more progressively (and this can be felt more clearly in the steering). I think it was Turtle on this forum who pointed out that you don't see F1 cars running on 17" rims with 35-profile tyres - although they would look so much better, there must be a reason why they don't... Rubber is heavier than alloy, too...
If the width of the tyre is correct for the width of the rim, the tyres won't look like balloons anyway. I like the sidewalls to be vertical
Correct width for 16" wheel according to my Spider handbook is 6.5". Tyre for that wheel is a 205/50 16. The handbook also specifies a 15" steel wheel, 6" width, and 195/60 15 (so there you go! You have a rare survivor, a car bought by someone who wasn't talked into paying more for alloys...) it'd be interesting to weigh one of your steel wheels, it's probably lighter than the alloy wheel...
I have a friend who has 205/60 tyres on his 164 with standard alloy wheels (6" wide).
I have the same car, same wheels, but 195/60 tyres. Just that 10mm difference is enough to make the steering of my car feel lighter and more precise. To be fair, his tyres fill the wheel arches better; and as a bonus, they rub a hole in the wheel arch liner in the delicate cambelt area
I think many people fit over-wide tyres and in 60-profile, they can indeed look like balloons!
I have 17" wheels on my 156 - the looks are worth it - but again I'm careful to run the specified 215/45 tyre size on the 7" rims.
On the other hand, sometimes you see 195 tyres on 8" rims. I think that fashionable stretched look is hideous, and I'm sure the tyre manufacturers don't intend their tyres to be used that way.
One of my first cars (Austin Princess) had a stupid choice of standard-specified wheel and tyre size. There were a few things wrong with that car but the choice of 4.5" rims and 185/70 14" tyres made the tyres look like balloons even when inflated to 40 psi, and driving into a street at anything more than walking pace produced a comedic squelching/squealing sound reminiscent of American cars in cheesy movies
looking back I'm glad I had the experience of such a car, it must be terrible to start out driving a Ford Focus or some other car with class-leading handling and never appreciate what that means...!