Different rear/ front mechs for a double and tripl

[Guest]

I have a Giant TCR2 that I have had for a couple of months now. Great bike, lovely to ride but the one reservation I had before I bought it was that it came with a triple chainring set ( Shimano 105 52,42,30 and a 12 - 25 cassette ). Its not too hilly where I live and my preference is for shorter faster rides as opposed to all day tours. I have not needed to use the 30 yet. I am only 35 and 160lbs and consider myself fairly fit so I am considering converting to a double ( 52, 39 ) and 13 - 23 cassette. A setup I have used over the last 20 years.
I have read many of the previous posts on the double v triple question and understand that I can simply replace my 30 and 42 rings with a 39 and change the rear cassette without any problem. However will the rear mech and also the front mech require changing ? I have read in some adverts that different mechs are available depending on wether or not you have a double or triple.
Opinions welcome.
Thanks in advance.

Keith, Formby, England.

 

[Guest]

That's strange. The TCR 2 that I bought came with double 53-39 and I have a cassette of
12-23. You will find it quite hard to set your own ratio unless you buy a complete cassette.
In my case, I want to have an 18,20 so that I can build a 12-20 and I have been told that Shimano doesn't sell them seperately....( what a ripoff !!). For the type of race I do , thats' what I need, but for the time being the original cassette is ok.

 

[Guest]

Now, to answer your question. I don't think you need mechanical changes. Maybe only a few adjustments. Better check with your bike shop

 

[Guest]

you can probably "get by" with changing (removing the 30, replacing the 42) the chainrings and cassette.

BUT, to do things right, and make it a true 18 speed bike, you will need to ...

1. change your bottom bracket to one with a shorter axle
2. change your front derailleur
3. change your left shifter/brake lever
4. change your crankset
5. going to a smaller rear cog (23 vs. 25) may mean
shortening the chain