[SloopJonB]

I despise wire running rigging. Unless your halyard is all wire, the sheaves are configured to handle both wire and line. Changing to all line the same size as your existing tails is a matter of joining the tail of the old to the head of the new and hauling them up & over. I've done it many times.

 

[SloopJonB]

What are the minuses to wire running rigging? What do you gain by changing it out?

The minuses are that it is too thin to get a grip on, you can't clearly see crossed lines at the top of the mast and it has meathooks that tear sails and your hands. On top of all that it requires rope to wire splices that you will almost certainly have to pay for since few owners can do them.

You gain the loss of all those things by changing to all line.

 

[SloopJonB]

Unless you have reel winches with entirely wire halyards, the sheaves will be able to take rope as well - they have to accommodate the rope tails. I have changed rope to wire halyards to all rope several times with no sheave problems.

If you have reels with all wire halyards the sheaves can be too narrow to accommodate anything larger in diameter than the wire you currently have.