Originally Posted by velofinds

I have a Viner that uses a 20" Vittoria tubular. According to Vittoria, they measure 21mm in width (same as their 22, 24, and 26 inch tubular tires):

https://www.vittoria.com/tire/juniores/

I'd like to get 20" clincher wheels for this bike, and most modern rim manufacturers offer them in ISO 406 or 451 only. Is there any way to determine if an ISO 406 wheelset will be compatible?

TIA.