So, I upgraded my crappy WalMart SUPER AWESOME ROAD TECH road bike to have Shimano Sora brifters. The original shifters were Shimano Revo downtube suicide shifters.
After doing so, I wasn't able to get my front derailleur to get to the third cog. The outer limit screw wasn't helping and i basically had to throw in the towel and bring it to my LBS.

Upon doing so, I said "what the hell? Lets get a full tune up while we're at it." besides -- it was set up from WalMart to begin with.

I picked up my bike today at the shop and the guy explains to me that the front derailleur was a Shimano mountain bike mech and it wouldnt work with my Sora Shifters - so basically he made it so i can only shift to the second cog and not to the third at all.

welllll I dont like that... at all -- I want to be able to go fast... thats why i like this sport

Anywho -- I'm just looking for input here. I'm obviously going to do a bit more researching, but i'm on a super tight budget and wondering if anyone knows of a good and CHEAP front derailleur.

I'm assuming the Shimano Sora 3303 triple would work, but how do i tell if its meant for road biking or mountain biking?

Also, if I find a derailleur that is used for, say, a 24 or 27 speed, would it still work for a 21 speed?

Thanks in advance for help! I really appreciate any input you can give me.

1st get a different mechanic. They keep saying that there is a difference in cable travel on FDs so that they can sell the more expensive ones to roadies - kinda like selling nitrogen to fill the tires to the BMW owners....

Are the brifters you got for double or triple? I strongly suspect that is the issue. If the FD worked before, and it was not damaged since, there is nothing wrong with it.

If you are in a relatively flat area, I would adjust the FD cable so that you have the big and middle rings and eliminate the granny ring.

We are talking about this: 700c Genesis RoadTech Mens Road Bike - Walmart.com correct? The one in the picture has stem mounted shifters, not down tube.

it would be nice if everyone who answered questions with such authority
had at least some small idea what they were talking about

shimano road and mountain derailleurs
absolutely have different cable pull requirements

this is not an issue if you have non indexed front shifters
but if you have road indexed shifters
that you need a road front derailleur
and the same if you have mtb indexed shifters

and to prove this is not all some scam
shimano makes some of its front derailleurs in both flat bar
and drop bar shifter compatible models

The Sora triple shifters are 3303, 3403, 3503, 3x00 are for doubles. I doubt that your mountain type front derailleur will work. Sora components are all designed for road bikes. The Sora shifters are designed to work with a bottom pull front derailleur, with the cable running under the bottom bracket through a cable guide, doesn't necessarily need to be a Sora. These can be added to your bike.

Shimano's mountain bike and road bike derailleurs are designed for slightly different cable pull ratios. Road shifters will obviously pull cable and move the cage on a mountain derailleur, but not the exact amount to shift from one chainring precisely to the next.

The Sora name is only used on road parts.

Awesome -- Thank you all for your answers -- I'll pick up a Sora triple front derailleur and call it a day, i suppose!

Thanks again guys - i appreciate it