Hello Andi Here are my three suggestions i) Racer...they produce a bare narrow alloy of nearly that diameter. ii) Cartrix ....their alloys are close too iii) munter sourced rims....tire bead 14.55mm, centre rib 16.4mm
These are the same rims before a little lathe work I used on my VRAA Vanwall (sad story that) I use long 4 or 5mm grub screws on them, cant remember which.
* you will never see chrome wheels on a racing car - the acid treatment prior to plating weakens the spokes.
Alan, I think you will find that it is hydrogen embrittlement which causes the problem. These days there are ways around the problem, with the parts being baked after plating. Years back, this solution was not known, but the fact that high tensile steels were more susceptible to the problem was known. Thus, no plated spokes.
Early race cars sometimes did have chrome spokes and highly polished rims, but not for racing.
You are quite correct, Peter. The issue is not an "acid bath" per se but a byproduct of the electrolytic plating process during which, in addition to the deposition of the chromium, there is ionization of the water-based solution with the resultant concentration of hydrogen ions at the surface (a defacto acidic condition) The baking removes this acidic film before the ions can re-form molecular hydrogen.