advice cassette sizes?
 

Im looking to buy a cassette (9spd) but when I go to order one it gives me the option of
011-21, 011-23, 012-27, 012-21, 012-25, 012-23
What does all this mean? Also, what is the common size chosen?
Oh yeah I found a good deal for a 9spd Ultegra upgrade kit but how do I know whether the rear derailleur will work on a triple or double crank? It seems I know just enough about components to get me into trouble, any advice would be appreciated.

Thanks,
Matt

What cassette do you have now, and how well is it working for you?

The low number (11, 12, occasionally 13) is the number of teeth on the smallest cog. The smallest cogs are for going faster. The high number (21 to 27 on road cassettes, up to 34 on MTB cassettes) is the number of teeth on the largest cog. You would pick a larger size if you need a lower gear for climbing.

The rear derailleur doesn't care about the number of chainrings on your crankset.

What are you upgrading from?

Go visit www.sheldonbrown.com if you want to learn a lot about drivetrain parts. His gear calculator will help you determine the effects of the various cassettes you might choose.

RichC

The numbers are the size of the chain rings. 11-21 means that the smallest ring has 11 teeth and the largest 21 teeth. The other 7 rings fit somewhere in the middle. Depending on what type of riding you are doing and how strong you are you can choose which size rings you will need. The larger rings are better for climbing so if you live in really hilly area then 25 or 27 teeth is nice to have. 11 tooth small rings is very hard to push and 12 is usually the minimun for us mere mortals.

Haha, Im upgrading from a 1980's schwinn I hijacked from my stepfather. I liked how much faster road bikes go now Im actually getting into it. I bought an argon 18 frame and am building up from scratch. I used to fix up bikes at a sort of goodwill bike shop and figured it cant be much different. So far so good, thanks fior the advice :)

One note about the rear derailleurs: the "arm" that holds the two chain rollers often comes in long-arm and short-arm versions.

If you go here and click the links for the two types of rear derailleurs, you'll see the difference. A long-arm version is good for a triple crank (it'll work with doubles too). The short-arm version is for doubles, it would have problems taking out the amount of chain slack on a triple.

You might want to divulge the full scope of your upgrade plan, so we can help you spot potential hang-ups :)

Take your time and watch the sales, be willing to mix and match, and you can do pretty well buying parts. Most of the modern Shimano road bike parts are interchangeable (Tiagra, 105, Ultegra, most Dura-Ace) so you can do well buying one part at a time. Even better are "take-offs" -- new, never used parts taken off new bikes by buyers who prefer a different spec. You'll see a lot of those on ebay.

Just be careful about some of the specialized tools that modern bikes need, such as such as splined sockets for cassettes and bottom brackets.

Those Argon 18 frames look really nice.

RichC

If you do not know what it means I must assume you do not race. I would not recommend any of the 11 tooth cogs because of this. Most road bikes are geared high for racing and unless you race this will probably be a useless gear.

That leaves four options: 12-21, 12-23, 12-25, 12-27.

If it is really flat and no hills get the 12-23. I would not get the 12-21 as this is also a pretty high gearing for non racing.

If you live where it is hilly get either the 12-25 or 12-27.

Thanks for all the info, I ended up going with a 12-25. I dont know if any of you are familiar with the massachusetts area but theres a killer hill around jiminy peak I ride up when I feel like punishing myself haha so the 25 should help with that. right now I still have a sizeable amount of parts to get; crankset, pedals (clipless), griptape, tubes, seatpost, seat, shoes, and brakes. I saw this shimano 105 hollowtech crank in nashbar that was actually lighter than the ultegra plus its cheaper. Should I go for that? Now that I think about it what are some good sites to shop for components? Also, yeah you guessed captsven I dont race but hopefully Ill get a chance to enter in a couple this summer. How do I get my liscense for that? The only hangup so far is that I got headset size wrong, 1 instead of 1 1/8. Ironically performance sent me the "wrong" size diameter for the stem and it turned out to be 1''. One more question, where should I go for advice on getting in shape for a race? I ran x-country and track in hs so Ive got a few of those muscles left but I went for a ride last week with the local bike racing club and got trashed so I guess Ive got a little to work on eh? Sorry about all these questions, teachers used to hate me for that lol.

Talk to the folks you ride/race with. Some of them may be racers and can help you. Ask at your LBS too.

I would recommend paying attention to your gears when you ride. I use a 13-25 right now. I run a decent spin so a 53X13 is a high 30s gear for me and I don't need a higher gear then that. A 25 will get me up the steepest hill in the state of FL without a problem and fortunately that isn't too far away.

Shoot if you have a decent spin even a 14 small cog will get you over 30 mph and for many people 30 mph is fast enough. I tend to think that they over gear bikes now a days.

Of course, I rode back in the days of 5 gear freewheels and back then people used to scheme endlessly over how to optimize their gearing set up. So I still have the inclination to try to have every cog in my cluster useable. You really don't have to go to that bother anymore what with 9 speed clusters and if you seldom use a gear who cares? You have 8 other ones.