And, just to clarify for all- if your bike is stolen from your vehicle, your renter's insurance or homeowner's insurance would cover that (minus your deductible if not "scheduled"-usually if it is scheduled on a floater, there is no deductible). Auto insurance does NOT cover personal property inside unless it is permanently affixed.
An umbrella policy was mentioned above as well. A personal liability umbrella policy is extra personal LIABILITY above your home & auto policies. So, for example, you cause an auto accident & someone dies, the attorneys may sue you for your policy limit of $300,000 or $500,000. Your umbrella would cover $1 mill to $5 mill above those limits (depending on how much you purchased).
This is totally separate from personal property that you, personally, own such as furniture, clothing, dishes (a bicycle), etc.
This is why it is a good idea to review your insurance policy every year. HOPEFULLY, your agent calls you on a regular basis to do this.