Cassette question

You have a whole lot more choices than the two you mention.

What gearing you need ie which cassette depends on your strengths as a cyclist and what type of terrain you ride. I think I have 6 different cassettes and I ride with different ones depending on the terrain I'm riding.

Great place to get them if you know how to change them yourself (it isn't hard to learn if you don't but you need two tools specific to cassette changing) probikekit.com

If the gearing you have currently works well for you ie you don't struggle up hills and wish you had another easier gear or two, stick with what you have.

First number the 11 or 12 you mentioned is the gear you would use when going fastest, the 23 or last number is your easiest gear. The number reflects the number of teeth on the cog..so a 11-23 has 11 teeth on the smallest cog and 23 on largest.

If you are replacing a cassette that has missing, some are made to have missing teeth, you probably want to get a new chain as well.

Along the same lines of this thread, I have a 12-25 Shimano Ultegra 9 Speed, stock. If I want to replace to get a higher number of teeth, lets say, cause I suck at climbing, can I replace with a 10 speed or do I need to replace with a 9 speed?

Replace with a 9 spd. 

If you don't have one already, you might actually be better off getting a compact crank with a 50 tooth & 34 tooth chain ring.

Missing a few teeth, really?

Like Kathy said, you have more options than that.  Count the teeth on the tiniest and the biggest cogs on the cassette, then you'll know what you have.  Let us know.

Thanks

9 or 10 speed?

Nashbar right now has 9 speed ultegra for $50... and you can get
11-21
11-23
12-23
12-25
12-27

They also have 10 spd. Ultegra 6700...
11-23
11-25
11-28
12-23
12-25

If you have 10 speed, I'd probably go with another 105, actually...largely b/c I'm cheap, and I've not seen a ton of difference between my Ultegra my 105.

Might as well get a new chain while your at it then.

Many cassettes will also have the number stamped on them somewhere, if you look.

Thanks for the feedback. Took the plunge and bought the Ultegra 9 Speed 12-27 last night from Nashbar. I have all the right tools, and I think I have a good head on my shoulders. How tough is it to change myself?

Here is a video that shows it....lots of other great videos on the site that show to do bike repairs or maintenance.

It turned out I had a 9 spd 12-26 cassette.  I wentto my LBS and bought an Ultegra 12-27 for $60.00 .  i also bought the tools I need to change it myself.

Thanks for all the feedback

Edited by MrSolis 2009-09-15 11:29 AM

if you dont know how to change the cassette you could always use youtube or google videos.  If a solution does not pop up there it doesn't exist.

With modern 9/10 speed derailleur they have the same reach. The shifters control whether it is 9 or 10 speed. I you wish to swap to 10 speed, u would need new cassette and 10 speed shifters