Is it grammatically incorrect to use the phrase, 'your details need updating' rather than 'your details need to be updated'?
I think that structure is more common in the UK than in the US. I don't know about elsewhere.
If you say "Your bike needs fixing" it will sound distinctly Southern (US dialect) to me.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.