First of all thanks for checking the post. I'm a total noobie to fixing and choosing bike parts. So I'm in the market for a new bike cassette since the one that came with my bike is about 3-4 years of use and is starting to show since of wear and tear. I have a Scott Speedster S50 2010, and came with a SRAM PG-850, 12-26, 8-speed Cog set. So my question is not only what you guys recommend, but how I should choose one. I've gone to several bike shops and ever single person makes it it seem like I'm disturbing them, or just don't want to help a noobie. Btw, I'm a casual biker, I use my bike to get to work and back, with the occasional bike ride.
A quick google tells me that bike is a triple; I'd put the tightest cassette I could find on it, like a 13-21. Close ratios are sweet, and the triple means you still easily have enough range for just about anything.
For your question, when you say shows signs of wear and tear, is this cosmetic, or physical? a cassette can look worn after a few rides, but not have any real wear for thousands of miles use. What is the chain doing when riding? if it's jumping, the cassette is probably worn, if not, would leave it until this starts.
If the cassette is worn out, you will also need to replace the chain (would replace with any change of the cassette), would be looking at the condition of the chain rings (on the crank) and the pulley / jockey wheels, as after 3-4 years, all of these may be worn out depending on how much the bike has been used.
For the bike shops attitude, if you are a 'noobie' swapping a cassette is a pretty specific thing to do, and indicates some knowledge of bikes, so maybe they think you know more than you do, perhaps ask them more general questions rather than being specific to give them an idea of your level of knowledge of bikes.
For your choices, why not just stick with an 8 speed (changing to 9/10/11 speed will be very expensive) and stick with the same ratios as you originally had. What about a SRAM PG-850 12-26! & a new chain.
13-14-15-16-17-18-19-21 with a triple crank is the best 8-speed setup.
The spacing is perfect, 30x21 is like 42x28 and enough to get a fit rider over everything in the Rocky Mountains spinning most of it, and even 50x13 is a plenty high enough gear (Eddy Merckx dominated the spring classics with a 52x13 big gear, and you're no Eddy).
I rode that setup in Boulder, CO with Rocky Mountains west and plains east so I wouldn't want to change wheels or cogs depending on where I decided to ride that day from 1996 until Campagnolo discontinued 13-21 8 cog cassettes in the early 2000s at which point I changed to 13-23 9 cogs.
The first thing I'll say is that I've had terrible experience with SRAM cassettes in that price range. The Shimano cassettes I've used at a similar price last 2-3 times as long, and they'll be compatible with what you have.
Where do you live? Do you ride many hills?
My guess is the stock gear range (12-26) is probably about right for your use. The standard Shimano setup is 12-25 or 12-23. The 12-25 would probably be a safe bet.
I haven't tried it yet, but I'd assume (and I've heard) a 9spd chain goes pretty well on an 8spd drivetrain and also doesn't wear significantly faster, I'm told (unlike 10spd).
I have a feeling you'd have to try harder to get chain rub, and it could tolerate slightly worse chainline, so you could be lazier with your FD.
Originally Posted by DArthurBrown
The 12-25 would probably be a safe bet.
This sounds incredibly conservative to me; the OP has a granny ring. For comparison, I run 42/52 x 13-23...
And as mentioned, nobody with a decent-sized big ring needs smaller than a 13, unless they're some sort of downhill speed demon, or maybe a gorilla bent on destroying his knees.
30/40/50 x 13-21 means the middle ring is good for the flat under pretty much any circumstances and will get you up mild grades or even short steeper ones, and when you have a tailwind you won't need to shift to the big ring until you're doing 40+kmh. 30 for uphill, 50 for downhill. And no horrible gaps between gears.
I've gone to several bike shops and ever single person makes it it seem like I'm disturbing them, or just don't want to help a noobie.
I know that feeling well in many stores that I wondered why they were still in business.
Last Sat I walked into one of my LBS, and the OWNER was still quick to recognise my prescence as he walked by. He told me he was already helping a customer but would have someone find what I needed. What a difference. Keep looking until you find one that deserves your money.
I think the other posters gave you enough info to digest. Is your next post going to be how to install them?