Road Cycling - Triple to doulbe conversion

I've had my bike for three months now, it has a triple and everything I've ever rode before was a double. I have tried it out for long enough and concluded that I want a double. Doubles just shift so much smoother and you can use the full cassette on both chainrings (right?). I don't like having to micro-adjust on the middle chain ring, and I also think I'm strong enough to do without a granny gear, albeit I have used it on occasion. So what all do I need? New crankset, bottom bracket, chain (not sure), front derailer. I've heard that the third setting can be locked out on the derailer, but won't it still have the micro-adjuster? I also think I might want to switch the casette to a 12-25 or 27. Will there even be that much difference between the granny gear with a 23 compared to a 39 with a 27? Also if there is anyone out there who wants to trade let me know. Thanks

In your current setup, shift into your 30-21 combination. That's going to be a very good approximation (just a hair bigger) of your smallest gear (39-27) when you switch to a double and the new casette.

i had this very same question and this post has some replies from folks.

http://bikeforums.net/showthread.php?t=50910

-m

Doubles just shift so much smoother and you can use the full cassette on both chainrings (right?).

Wrong. According to Shimano the only place you can use the full cassette is on a triple on the middle chainring. You should not use Large CR / Large cog or Small CR/ small cog on a double or a triple.


I don't like having to micro-adjust on the middle chain ring

You have to micro adjust on BOTH chainrings with a double.

You need to change the cranks, bottom bracket, front and rear derailuers. Technically, you can use the rear der, since the only difference is that it has a longer cage. But, that is the whole alledgedly "smoother shifting" thing down the drain.

So, with the things that you stated, a double is not going to help.

You have to micro adjust on BOTH chainrings with a double.

Thats not what I remember when I test road a cannondale R600. It had the same components and everything.

There are four "clicks" on the front shifter. The same shifter is used for a double or triple. On the triple it gives you one position for the small chainring, two for the middle, and one for the large. On a double you have two for both the small and large chainring.