You are reading a single comment by @Rik_Van_Looy and its replies. Click here to read the full conversation.
  • ^ French 531 was Metric OD (28.0 not 28.6) so plain had ID 26.2, and DB 26.6 (or 26.4).

    Unlikely that this is a French frame though, what with it coming from Bolton.
    Easy way to find out would be to stick vernier around the seattube...

About