jans

I ride indoors during the week and outdoors on the weekend. I have a dedicated bike for the trainer. This is a Specialized Allez Expert I bought in 2008. For years I have been complaining about the shifting and it has reached the point that I want to do an overhaul on the components. The problem is that this bike has a triple ring in the front and the shifter for the front derailleur does not function well. Indexing the gears is also difficult because of the wide range, even though I never use the smallest ring in the front. Keep in mind that I do not need brake calipers, which other components would I need to purchase to make this switch ? Shifters, front and rear derailleur, crankset. Anything else ?

SpedFast

Seriously, you may not need anything new aside from cables, chain, and grease/oil. Your front DR is probably just not smooth because (taking a guess here) the cables are worn, both inside cable and housing. Do you know what you currently have for a drive train? 3X? Help is headed your way, but give us a little more info about your existing setup.

spelger

I upgraded back in December last year. Went from triple to double, 8 speed to 10 speed. Needed shifters, cranks, bb, front derailleur, rear derailleur, associated cabling and housing. Glad I did it.
and cassette of course.

jans

I took it into the bike shop for a full tune up earlier this year including new cables, new chain. It worked well for a few months but it feels as if it is back to where it was before the tune up. It is Ultregra drivetrain, 3 x 10. If I go forward with this, I would go to 105 components

Sy Reene

If you use for Zwift (?), you could perhaps consider reducing trainer difficulty somewhat. Likely you could get bike to have enough gearing range just keeping the chain on just one of the front chainrings and remove need to worry about the FD shifting.

clasher

If you've 3x ultegra, make the change to 3x tiagra, I used it and it works better than the 6700 stuff it replaced. The only thing I notice is the aluminum levers when I ride in the cold, they suck more heat from my fingers than the carbon ones on the ultegra. I went through one rear derailleur in 10,000km but otherwise it's been pretty solid for the price. I stuck with 10 speed since chains and cassettes are cheaper. The 4700 stuff uses the same designs as the 11 speed groups so it's lighter shifting than the old stuff.

Canker

Or just throw a bar end shifter on it for the FD. It is just on a trainer and you aren't going to shift the front mech much anyway. I'm cheap so no way I'd bother with 105 for a trainer bike. If I were going to upgrade everything I'd jump on aliexpress and pick up one of the Sensah complete groupsets for $200 and something.

himespau 

I personally, am a big fan of the microshift mechanisms when building up shimano-compatible bikes for my family (I prefer Campagnolo, but no one else rides enough for me to make that investment). Give their 10 speed stuff a try.