My experience with rims with less than a 14mm inner diameter has been negligible and my understanding is that not many clincher rims are available that are much narrower than that. I stated "extra narrow" followed by a qualifying measurement of 14mm - I would personally consider anything less than that to be "extra narrow."

I have a lot of experience going downhill and cornering on 14mm ID rims with 1 1/4" or 32mm tires and I can tell you from experience that at speed it is possible to feel the sensation of them deforming over the lip of a narrow rim, which is something that is not experienced on the same rims with more narrow tires. Hence the point I shared above about stability and steering control. As I mentioned, I don't see any safety concern as far as the tire actually rolling off of the rim, but a wider rim under a 32mm tire would certainly offer more support and less tire deflection, or vice versa.

Here's a handy chart from Sheldon Brown that I know many people would say does not paint the full picture because there are so many considerations about the quality of the rims and tires. However, it gets a point across that I firmly believe, which is that there are ideal combinations both from the perspective of safety and performance:


Tire Sizing Systems

-Gregory

These measured 19.5 at the rim brake, inner not measured.

the tire is Specialized 1 1/8” with a center rib for ‘efficient rolling’ that made it squirrely on any turn. Terrible tire.

On a tall (62cm) bike, 27” does not feel quite right, for fast riding.


Came on a ‘71 PX-10, No idea what might have been original to that bike in USA.

I’m not sure what was up with some of the earlier 27” tires. I’ve had several used bikes pass through my hands that had 27 1/4” marked tires that measured at 25 mm or perhaps less. These were on skinny 13mm inner width rims, but it was easy to see that they were never going to be wider even on wider rims. Inflated, they were not tall at all so had nothing extra to widen out with. I just wondered why they marked them such.
One brand I do remember was marked “Armadillo Technology”. It had the thickest, nastiest tire casing I’ve come across. It felt inflated even with all the air out. Into the trash these went.

All my bikes are 62 or larger and a couple of 64cm frames . A few have 27” wheels and really no difference to me . They run the blue label Rigida like you show and I have 1” or 1 1/8” Pasela tires. They ride nicely , but I don’t ride that fast , mostly about 17mph on the flats. Smooth and comfy and corner very well even on fast downhill blasts. The 700 wheels are mostly Super Champion wheels with 25 or 28 wide tires of the same brand . They all ride nicely for me.

Possibly not relevant (an older 27X1 1/8 tire) - but just for the record = the Specialized tire shown above with center ridge measures less than 23mm at full inflation (22.8 avg, taking 3 measurements on each of f/r tires).

If you are using width to stand in for height - the height can't move very much, that's just the size of the tire circumference when it's all strained out. It's probably nearly the same in spite of rim width. But the width at the widest point is definitely being taken in a lot by skinnier rims. Paselas are 33 mm wide on my Paramount but the same ones are 29 mm wide on these skinny Rigidas

That said the Serfas I pulled off the Rigidas measured 27mm, 2mm narrower than the Paselas despite being the same listed size and a lot thicker carcass

Good Match, excellent price...?


Amazon

Man, those crazy things you find out in the workshop.