Am I too old chair?

Unfortunately, I realized that the mounting pins ~ sticking with my old 30mm wheels, but here only ~ 20 mm. Although the pin fits in diameter, but does not lock and the role falls back out of the bracket on the chair.

Probably it is because I wanted to equip a 15-20 year-old chair (Interstuhl) with it, because in a recent Noname fit the roles and do there best in service.

Therefore, the Council: Previously times deduct a role and measure!