Can i change a double crank set into a triple with out changing shifters etc

[dickyjones]

hey i have a specialized allez elite 2006-2007 double front crank, back 8 gear road bicycle with shimano 105 derailleurs & brake system.. i want to know if i can change my front double crank set for a triple crank set without changing my derailleurs & shifters? it feels like i have one extra click on each shifter if that makes any sense, like i have an extra shift but no cog for it to drop on to.. please any advise would be appreciated, thanks.

[JonB]

Hi

Possibly, take your drive-side crank off and have a look at the inside face of the drive-side crank arm.

If you have four or five posts with threads on the inside then you can fit a granny ring in. Don't quote me on this but 105 shifters and mechs should be fine (the mech certainly).

Pictures of the crankset from multiple angles would be useful if you can.

[cyclerUK]

Some Shimano shifters will do both doubles and triples but the majority don't.
Double shifters usually have 1 or 2 extra clicks and these are for trimming purposes.
(ie - to allow the derailleur to be moved fractionally to stop the chain rubbing it.)

Do you have the model / part No. for your shifter.?

I would expect you will also have to change the derailleur to a triple version.

[Joe_W]

Well, depends on the dérailleur, you might have to replace the rear dérailleur (teeth capacity, that means how much chain slack can the dérailleur compensate for). Same goes for front one: they are designed for a certain minimum and maximum number of teeth.