Bicycle Mechanics - Drivetrain upgrade

My shimano 105 8-spd shifters (ST-1055-T) have gone kaput and will no longer shift from large rings/cogs to smaller. If I want to upgrade to 9 or 10 speed, what components need to be replaced? Obviously, the shifters and the cassette, but what about the derailleur and rear hub? My web searches so far have given limited and mixed information. Do I need to replace the front derailleur and crankset? Why would that be? (Currently it's a shimano 105 triple).

Thanks!

Search this forum, topic discussed many times, but here's the short list:
Shifters - yes
Cassette - yes
Chain - yes
Rear Der - no (for 8 to 9, probably 8 to 10)
Front Der - maybe/maybe not; will have to tweak it some, fer sure if going to 10)
Cranks - no
Hub - no (8,9, 10 all the same width)
Bar tape - most defintely!

My shimano 105 8-spd shifters (ST-1055-T) have gone kaput and will no longer shift from large rings/cogs to smaller.

Why?

You sure you don't want to figure that out first?

Might need new cables. Might be FD/RD adjustment. Might be sticky shifters. Might be sticking at the cable guide on the underside of the bb shell.

You sure you need to upgrade?

Just sayin'.....

I had a similar problem earlier this year. I switched my shifters to Campy Veloce for $114 shipped from GVH bikes and added a JTEK Shiftmate ($35) to mesh the Campy shifters with the Shimano rear derailer.

Search this forum, topic discussed many times, but here's the short list:
Shifters - yes
Cassette - yes
Chain - yes
Rear Der - no (for 8 to 9, probably 8 to 10)
Front Der - maybe/maybe not; will have to tweak it some, fer sure if going to 10)
Cranks - no
Hub - no (8,9, 10 all the same width)
Bar tape - most defintely!

Thanks. I tried the search and sifted through a lot of stuff without getting the complete picture. Please forgive my lack of knowledge on the subject. For example, why would you need to change the front derailleur (even if it's just a maybe)? How does changing the number of cogs have anything to do with the front derailleur.

Why?

You sure you don't want to figure that out first?

Might need new cables. Might be FD/RD adjustment. Might be sticky shifters. Might be sticking at the cable guide on the underside of the bb shell.

You sure you need to upgrade?

Just sayin'.....

The shifters are definitely broken or maybe just sticky but I've tried cleaning them out with WD-40 and lubing but can't get them to work. No clicks at all unless you really struggle and fiddle with it. Actually, after my attempt to clean and fix the right one, it has problems shifting to larger cogs as well. Seems that I can do about 2-3 clicks up and down but then it's stuck.

And I'd rather not go through the upgrade hassle, but where do you find 8-spd shifters these days. I've only seen mostly 10-spd and some 9-spd.

I had a similar problem earlier this year. I switched my shifters to Campy Veloce for $114 shipped from GVH bikes and added a JTEK Shiftmate ($35) to mesh the Campy shifters with the Shimano rear derailer.

Thanks. I checked out the JTEK web site. So for $35 plus the cost of new shifters (9-spd) I could potentially be good to go.