[jlandry]

I'm buying a used bike with a Shimano 105 triple, and want to change it to a double.
Do I have to replace the whole crank... or just buy new rings and modify?

Edit: Will the 105 derailleur still work with a double setup?

 

[wim]

Some thoughts.

- if you want a "true" double crank, you need to buy a new crank.
- if you want a true double crank and all the proper double stuff that goes with it, you also need to buy a double front derailleur and a short-cage rear derailleur. And unless you have an external bottom bracket, you need to buy a new double-specific bottom bracket (shorter spindle = narrower tread).
- if you want the effects of a double without the expense, just don't shift into the smallest ring. Or take the smallest ring off and re-adjust the front derailleur limit screw.
- if the triple outer- and middle rings are not to your liking, you can get larger / smaller rings.
- triple front derailleurs will work with a double (as will long-cage triple rear derailleurs).
- probably forgot something, but someone else will chime in.

 

[Salsa_Lover]

yes a triple front derailer can be setup limiting it to two, this limits the front shifter too.

But a front derailer is kinda cheap so you could replace it.

If your cassette is a 12-27 you could also leave it with the triple rear derailer.

also I think if you remove your triple crankset, derailer and left shifter and put it for sale on the bay you'll get a lot of biders on it, and you can get double versions cheaper too.

 

[pennstater]

10 speed 105 5600 shifters were double or triple compatible.

 

[roscoe]

10 speed 105 5600 shifters were double or triple compatible.

originally they were, then after they had problems they came out with dedicated double or triple 5600 shifters

 

[pigpen]

Will a double front derailleur work with the wider Q factor of a triple crank?

I want to do the same. My 7803 is only 5mm wider on the drive side. Can the limit screws adjust that much?

 

[wim]

Will a double front derailleur work with the wider Q factor of a triple crank?

I want to do the same. My 7803 is only 5mm wider on the drive side. Can the limit screws adjust that much?

Yes, it will. There may be a combination of oddball front derailleur and really wide Q-factor triple crank out there somewhere that could make me a liar, but I seriously doubt it.