Road Cycling - Cassette for crits v. climbing, how about both?

Hey guys, I'm a little confused and I hope you can help me out.
I currently have a 12-25 on my bike (9-speed).
On the weekends, I do a lot of climbing. My typical ride is about 85 miles or so, and we'll do major two climbs for a total of about 6000ft. These rides have been going well, but, I'm thinking of getting a 12-27 so I can spin a little more.
I'm also going to be doing crits this season, and I was told that I NEED a 12-23 for the spacing to be ideal. Particularly, I need the 16. I've been thinking back on my groups 'fast' Tuesday ride, and realized that when we're really hammering, I'm missing a key gear...I can't get comfortable because sometimes I'm inbetween gears.

So I don't know what to do. I don't think I'll keep the 25, because it seems ill suited for both climbing and riding fast. Here are the options I came up with:
1) Get the 12-23 and compact cranks? I don't know anything about gearing, which should I get? Maybe just a smaller small chain ring? But then it would seem like the gap bw large and small chain ring would be huge...
2) Buy two cassettes, swap them every week?
3) Buy two cassettes and another rear wheel, swap the just the wheels every week?
4) Trying converting my 9-speed Ultegra to 10-speed Dura-ace?
5) Just buy an additional frickin bike. (Not really an option because I have NO money, but that's what I really want to do.)

I will be doing the same thing and I am going to choose option 2. An 11-21 or 23 with my current 12-27 for the mountains. My lbs is getting in a new tool shortly that makes cassette removal a snap. You fit it in the cassette on the bike and use the cranks to spin it loose. It will take 10 minutes.

I will be doing the same thing and I am going to choose option 2. An 11-21 or 23 with my current 12-27 for the mountains. My lbs is getting in a new tool shortly that makes cassette removal a snap. You fit it in the cassette on the bike and use the cranks to spin it loose. It will take 10 minutes.
Do you have to tune your rear derailer every time you swap? What is the tool called?

Cassette change will run you $40-50 for cassette and tool but if you have a lot of miles on the current setup you -may- have a chainwear/cassette incompatibility.
This tends to pop up in the 3-5kmi range. I generally get 2.5 chains per cassette. I suspect your road miles are going to be a lot more than your crit miles so it will not be simple but you really do need two different cassettes/wheels at your level of riding. That 27t cog will make you spin. Steve

I had different cassettes on different wheels for a while, but it was solely due to the fact that I'd ridden long enough to end up with a spare rear wheel. If you've got the tools to do a cassette switch, run lower gears when you need them and higher when you need them. If you replace your chain often enough, you shouldn't have too much uneven wear between the two.

I need to get a mountain wheel built up to put my 13-29 on. But there's other stuff to spend it on until next fall when I'm back close to the mountains again.

I know nothing of the tool that you use your cranks to spin the cassette lockring off with, and have no idea how you'd go about doing that, but hey, if it works cool. You may very well have to adjust your derailleur slightly to keep the chain lined up with the cogs. Or, make sure that both wheels are dished the same and you shouldn't have a problem at all. Chances are that one wheel will be a little off dish from the other one; use the one that's centered up best as your target for the other one.

Do you have to tune your rear derailer every time you swap? What is the tool called?
I have not gotten it yet. I was just talking about it last Sat. at the lbs. Now that you mension it a jump from 27 down to 23 may require some adjustments, maby even a shorter chain? So maby I will consider jumping from 27 to 25. But then is it worth it. I'll run down to my lbs probably next week and let you know more about it...

To calculate gearing:
Number of teeth on chain ring divided by teeth on rear cog multiplied by the wheel diameter in inches. This gives you the gear in gear inches. Multiply that number by pi(π) to find out how far your wheels traval with each turn of the cranks.

How about a triple chainring setup and a 12-23 cassette?

If not, I vote for 2 rear wheels and cassettes.

I'd go for 2 wheels. get a close ratio 12-21 or something for the crits and that 27tooth for the hills. If you have a fancy rear wheel, keep that for the crit :D

Brendon

I would go with the 11-23 option I did it and I climb alot. I'm not sure about your strength so you might be wise to get another wheel and use that option so you get the 12-27 and the 11-23.

waah? id keep the fancy wheel for the hills-crashes happen in crits and then things like wheels break...

My two cednts go with Sherpa!

I have a 12/27 I use for every day riding and an 11/23 I plan to put on when I race. I have a short cage Ultegra rear and my LBS tells me I may be able to get away without tinkering with it each time I change wheels. I will find out once I do it!!

BTW - I also agree with Pinky about the wheel!! The coow wheel will get you style points on how your bike LOOKS at the START line, but what matters is crossing the FINISH line in one piece (and hopefully FIRST with both hands raised)!!

Now that you mension it a jump from 27 down to 23 may require some adjustments, maby even a shorter chain?

Set the chain length for the 12-27. There is no need to shorten it when you change to a 12-23 or even a 12-21 for that matter since your small-small combo has not changed at all.

Set the chain length for the 12-27. There is no need to shorten it when you change to a 12-23 or even a 12-21 for that matter since your small-small combo has not changed at all.
ah yes makes sense, and so going down to an 11 from 12 is probably insignificant concerning the small small combo?