For all my 67 years, the most common and expected spelling in the USA is derailleur. So that's what I'm sticking with as long as Merriam-Webster and the other's say it's so.
Shimano and SRAM spell it that way too on their USA English language sites.
Just like all the other senseless name changing going on, changing the spelling of derailleur will cost money.
Last edited by Iride01; 12-21-25 at 01:05 PM.