General Discussion Triathlon Talk » Shimano 105 rear derailleur question Rss Feed  
Moderators: k9car363, alicefoeller Reply
2010-04-20 8:49 PM

User image

Regular
64
2525
Muncie
Subject: Shimano 105 rear derailleur question
I am looking at an inexpensive road bike that has 105 components except for the crank.  I want to replace the triple crank with a double but I don't want to change the rear derailleur if I can help it.  I have no problem with the front but the rear is a long cage version.  Can I keep the rear even thought I want to get rid of the Triple crank and put on a double, or if I put on the double crank will I have to change the rear derailleur?  Thanks


 


2010-04-20 9:28 PM
in reply to: #2805888

Champion
8903
500020001000500100100100100
Orange, Massachusetts
Subject: RE: Shimano 105 rear derailleur question
I am not speaking from experience here, but I am going to hazard a guess that you don't need to change the rear derailleur.  It has the long cage because of the amount of chain wrap required in the difference between the large outer chainring and the small inner chainring.  You won't need that amount of wrap up with a double setup...think of it as keeping your triple and only using the two largest rings.  If you ever do decide to go with a small cage rear derailleur, you could do so and shorten the length of the chain an appropriate amount.
2010-04-21 7:29 AM
in reply to: #2805974

User image

Slower Than You
9566
5000200020005002525
Cracklantaburbs
Subject: RE: Shimano 105 rear derailleur question
You will not need a new derailleur.
2010-04-21 3:56 PM
in reply to: #2806386

Veteran
480
100100100100252525
Subject: RE: Shimano 105 rear derailleur question
If the bike has STI shifters for a triple, then you'll have to fine tune the front to account for the missing ring of the double.  No big deal, as it actually allows you to "trim" the front if you get any rubbing.  You may have to drop the front down a bit as well if you are going to a compact crank, to account for the smaller large ring.  The rear is good to go as others have said.
2010-04-21 4:23 PM
in reply to: #2808270

User image

Expert
937
50010010010010025
Traverse Cityish
Subject: RE: Shimano 105 rear derailleur question
abier - 2010-04-21 4:56 PM

If the bike has STI shifters for a triple, then you'll have to fine tune the front to account for the missing ring of the double.  No big deal, as it actually allows you to "trim" the front if you get any rubbing.  You may have to drop the front down a bit as well if you are going to a compact crank, to account for the smaller large ring.  The rear is good to go as others have said.


Bingo!

I put a compact double in place of my old triple and I'm still using the same shifters, derailleurs and everything. I just had to set the limit screw to prevent the front from trying to drop to the small ring, it works great.

2010-04-21 4:54 PM
in reply to: #2806386

User image

Champion
16151
50005000500010001002525
Checkin' out the podium girls
Subject: RE: Shimano 105 rear derailleur question
But the short cage would save weight.

About 2gm.


New Thread
General Discussion Triathlon Talk » Shimano 105 rear derailleur question Rss Feed