Bike anatomy question

[SalsaMTB]

I also wonder what the shop said when they completed the tuneup. Normally, a shop will let you know if a part needs replacing.

My other question is, have you tried other bikes and felt a big difference compared to yours?

The reason I ask this is I don't know your experience level, so I apologize if this seems very basic, but there is a significant difference in feel of shifting to a harder gear with left shifter vs. right shifter. You said it feels like you have to hold the left shifter until it shifts, which I'm not exactly sure what that means, but I do know I have to push my left shifter much further to get into the big chain ring, than I ever push my right. When you use your left shifter to go into your big chainring, the chain has a lot more distance to travel so you have to push the shifter further, takes more effort, and is a bit slower. When you shift with your right hand, you're moving the chain along the cassette and the distance is much smaller so it's much quicker (the simple click feel).

If you have tried other bikes and feel a big difference, then yes, something is wrong (could be in the shifter, could be the derailleur, could be cables). You should probably take your bike in to the shop to have it looked at. If you haven't tried another bike and are just doing a simple comparison of your left vs right shifter, then I would recommend trying a friend's road bike . You may just need to get used to shifting the front derailleur. I definitely do not use the same motion to shift into my big chainring as I do to shift my rear derailleur.

[VeloVT]

The reason I ask this is I don't know your experience level, so I apologize if this seems very basic, but there is a significant difference in feel of shifting to a harder gear with left shifter vs. right shifter. You said it feels like you have to hold the left shifter until it shifts, which I'm not exactly sure what that means, but I do know I have to push my left shifter much further to get into the big chain ring, than I ever push my right. When you use your left shifter to go into your big chainring, the chain has a lot more distance to travel so you have to push the shifter further, takes more effort, and is a bit slower.

Agreed that shifting front derailleur DOES feel different (and is harder) than shifting rear derailleur. In addition to what SalsaMTB said, this is due in part to the fact that the front of the chain is under higher load when pedaling than the rear of the chain, making it harder to shift. Softpedaling for a revolution makes shifting up in front much easier.