breazer

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.

Cassette:

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.

Chain:

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!

jimbok1

My recommendation if this is the first time yo uhave had to replace a cassette, take it to a bike shop, either to have them do the work or at least to to buy the replacement cassette. discuss the type of riding you do and your experience level, this will help them figure out what you need. I would recommend a SRAM cassette and chain if the rest of the drivetrain (derailleurs and crankset are SRAM though shimano and SRAM are interchangeable, I have been told if possible not to mix them). The close spacing of 11 or 12 - 25 or 27 is more of a racing and flat area cassette. A 11 or 12 - 32, 34, or 36 will have a lower gear ratio better for climbing. If you don't have to walk up part of the climbs in your area 25 or 27 is probably best, If you find your self having to dismount and walk go with a lower geared 12 - 32 or 34.

dsbrantjr

If you are happy with what you have why not buy the exact replacement? Going to the PG-970 will save you like 10 grams for $13 more; leaving your keys at home will do the same.

As to the chain any "9 speed" chain will work; I always recommend a chain with a removable "master link" for ease of removal or replacement for cleaning and the like. Shimano chains require a special one-time use connecting pin and a tool to insert it. KMC, SRAM and Wippermann have the master links although you will still need a chain tool to shorten the new chain to the correct length. Provided your old chain was correctly sized you can just make the new one the same number of links. Here's an article on chain sizing in case you'd like to double-check: https://sheldonbrown.com/derailer-adjustment.html#chain. Make sure you thread your derailleur correctly, it's easy to do wrong, here's how to do it right: https://www.livestrong.com/article/48...he-derailleur/

Bill Kapaun

Once you exceed 27-28 teeth for the largest cog, you probably need a "mountain" RDER.
Bad advice to recommend larger without telling "the rest of the story"!

desertdork

IMO, 3k miles isn't much mileage on a 9sp chain...let alone cassette. Your chain broke, for whatever reason, and I'm not arguing against its replacement. But the cassette should last through the lifespans of multiple chains. I think there's a great chance you're rushing to replace your cassette much too early.

Get the 9sp chain you prefer, be it Shimano, SRAM or KMC. As you progress up the ladder, you get different finish/plating and possibly slightly lighter construction. You can use a connecting link with a Shimano chain, but it must be purchased separately.

IthaDan 

Lurk more. The first half of this is decent advice, seeing a chainwhip and lockring tool In use helps a LOT. but saying a 12-27 is a racing cassette and he should go with a 32 or 34 large cog is just bad advice. Why'd you even bring up the monster cassette? The OP didn't indicate they were having trouble climbing.

ON TOPIC: SRAM makes a 12-26 9 speed cassette, I have one. I don't know the difference between the 950 stuff and the 970 stuff. But I do know that there are better deals than nashbar for these two parts. I just made this purchase a couple weeks ago, il see if I can remember where I bought them from.

OP: ORDER THIS: I bought This and the 971, but the 951 price is good as well about three weeks ago. I have nothing to complain about, shipped fast, even got a price point sticker out of it the 971 chain and the 950 cassette work well together and with my 6500 STI levers.

breazer

Thanks for the suggestions. I think I'll stick with what I've got, meaning I'll match my current cassette with a new SRAM 950 and then a 951 or 971 chain. Now as to my mechanical skills, that's a whole other problem.