Originally Posted by
veganbikes
Except when not, as shown in my post above. 26" can also refer to ISO 559 for mountain bike usage. In typical road usage yes 26" is likely ISO 571 at least in this context but some companies have made ISO 559 road bikes.
I specifically said 26" tubulars, which are 650c diameter. This is a well established nomenclature. Just as a 28" or 27" tubular refers to 700c ISO 622 , not 27" ISO630. The OP asked about 26" tubulars, and those would be ISO571 650c diameter. Now maybe the OP meant to ask a different question, but I am just answering the simple question he posted.