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I want to change my 105 triple ring to a 105 double ring(7 posts)

I want to change my 105 triple ring to a 105 double ringRobby Canuck
Sep 16, 2003 6:21 PM
so other than buying new double ring cranks (I also want to go to 172.5 cranks from 170s) do I really need to invest in a new front derailleur and new rear derailleur?

I understand that my left shifter can be 'programmed' to handle the double.

Question 2...: The bike is a 2001 Trek 2200 with 6,000 miles on the orginal components. The rear cassette has 9 rings. The chain and cassette seem to be in good shape - but with that amount of mileage should I change them?

Thx for your input! :)
re: I want to change my 105 triple ring to a 105 double ringRusty Coggs
Sep 16, 2003 6:54 PM
You need the shorter BB for the double crank.The shifters shift either a double or triple,no programming.You can use the triple derailers. Cheaper way,just rremove the granny, replace the 42 with a 39 and readjust the derailer. Measure the chain.If it's stretched 1/16" or more in a foot replace it.
Pretty sure you need the triple FD. (nm)TFerguson
Sep 17, 2003 4:01 AM
Oops. Double FD. You know, the other one. (nm)TFerguson
Sep 17, 2003 4:08 AM
I am hoping to get by with the existing triple FD and ...Robby Canuck
Sep 17, 2003 10:32 AM
will try that 1st before dropping the $ on a double.

The funny thing is the RD - I would have thought that it would not matter if you have a double or triple chain ring - but Shimano makes RDs specifically for double and triple chain ring. They must have a reason - I just don't want to pay for it. :)

They may be associated with Microsoft in that regard ;)

I will see how it goes
The rear wil be OK...TFerguson
Sep 17, 2003 11:18 AM
The difference between the 2x rear and 3x rear is that the pulleys can take up more chain on the 3x. This is needed to go from a 30 chainring to a 52. Using the 3x on the 2x, you will not be able to get it as close to the cogs and shifting may be affected a little, but will work.

IMHO, you need a crankset, FD and BB.

TF
The rear wil be OK...Robby Canuck
Sep 18, 2003 11:13 AM
Thx for the info.

In order to save my sanity on this, I have decided that I will get a new FD and RD to go with the new BB and cranks. That way I can just sell my triple ring stuff as a whole unit. (if equipment with 6,000 miles on it has any value!!)