Theft, vandalism, fire, or being struck by a vehicle -- covered worldwide under my homeowners insurance, at replacement cost minus deductible. (Those are all standard perils covered by many homeowners packages in the U.S. Vehicle damage can be tricky -- if my negligence contributed to the loss, it may not be covered.)

Bike crash -- not covered by my insurance, but there are optional coverages available. You can buy stand-alone bicycle insurance, advertised in racing publications, that offers broader coverage than homeowners insurance. And there at least used to be separate policies available for bicycles, "floaters" or "inland marine" policies, underwritten by companies that specialize in things like that. I haven't been active in selling personal lines insurance for years, so I don't know if those are still readily available.

Specialized bicycle coverage tends to be more expensive than personal property coverage under a homeowners package. Who goes looking for specialized coverage? In general, people with expensive bikes who feel they're likely to need the coverage. In other words, people who are more likely to have a claim, and more likely to have a large claim. So the companies have to price it higher. But that higher price limits who wants to buy the policies -- only people who really feel the need for the coverage will pay the higher price. Which again means people more likely to have claims. It's a vicious cycle that affects many types of insurance -- that's why Obama's health care reform depends on an unprecedented mandate requiring almost everyone to buy private insurance, to eliminate this tendency for people to not buy insurance until they think they're likely to need it.