Giro Donne TT cancelled...

[SoreTween]

...due to rain.

Why isn't it mandatory for teams to have appropriate rubber available?  Sure a pair or G-Ones or Big Apples¹ will be slower but it would be safe & fair if every rider is mandated to use them particularly on a regular stage.  Would it work for a TT to declare the stage wet & everyone has to use them even if it dries up later?

Tear me apart for my ignorance by all means but the question is borne out of 'there's usually a reason and I can't see it' rather than armchair commentator knows best.

¹Not serious suggestions, I know they wouldn't fit (in their currently produced sizes).

[Frank9755]

Presumably safety as well as fairness

In a course with some tight turns the amount of grip available will be less than in the dry but not by a known amount, and is likely to vary according to how much rain, extent to which it dries, etc. So conditions different for different riders, and the winner is the one who takes the biggest risk without coming off,  which makes it a bit of a lottery.

[chrisbainbridge]

That was I thought well covered in the Netflix documentary where the TT star goes from a possible fret or second to 90th as a result of pushing too hard and coming off. The suggestion seemed to be that it was the road markings which were most dangerous. 

[rafletcher]

Images of Jan Ullrich losing the 2003 TdF as a result of falls in a wet ITT come to mind. So why stop the Giro Donne ITT? I guess it depends on how bad the rain / wind were, but I can only recall one recent TdF stage stopped because of IIRC torrential hail and a landslide. Mere wetness doesn’t seem to matter so much. We al know the paint is slippery. Perhaps riding it on standard road bikes as opposed to head down TT bikes could have been mooted.