Cassette & Chain - first time (novice) replacement - need help choosing parts
I have about 3,000 miles on a 7 year old road bike. Recently my chain snapped while on a ride and several good samaritan cyclists repaired it allowing me to continue biking (for the day). They advised me to replace the chain (an obvious recommendation) and the cassette as well.
I have no experience with either of these repairs, but I reviewed a number of websites and watched a couple of videos. The tasks do not seem too difficult. I figure the cost of the required tools (cassette lockring tool & whip and a chain tool) would be less than the labor charge at a bike shop. Plus I'd finally have the means of removing the cassette to keep it clean.
I looked on Nashbar.com and review options for selecting chains and cassettes. Knowing nothing about gears and ratios, the options only confuse me. My current OEM cassette is a 9 speed SRAM 12-26. Nashbar sells the SRAM PG-950 and SRAM PG-970 available with that size. Which one? Then there a numerous Shimano models, although these come closest in size at 12-25 or 12-27. Again, I know nothing about gears and ratios.
A web search for the specs for my bike (2005 Giant OCR 1) shows the chain is 1/2 x 3/32". I assume that is correct. I cannot find that spec amongst the choices on Nashbar for 9 speed chains. The prices range from about $15 for Nashbar-branded to $30 for Shimano.
Anyone want to dumb this down quickly for me so I can make an easy choice? I'm an average rider (15-17 mph for 40-50 miles with modest climbs, not mountains). Also, Nashbar is not a requirement, I just happen to be familiar with that website and it was easy to see my options.
Thanks for any advice!