I'm shopping for tools and parts for my new bike. What is the likelyhood of needing to repair a chain on a ride? Is it recomended to carry chain components on board? If so what should I get? I'm sure the pins come in different sizes, how do I know what size I need? The specs on my bike list the chain as 'KMC Z72NP' does that have any particular meaning other than manufacturer and part #? Thanks in advance for any advice offered.