Speaking of cheap bicycles
 

I've had this 21 speed Schwinn Aluminum Comp for about 3 years, and probably rode it 3 or 4 times. I was getting it ready to give to a neighbor kid whose parents can't afford a bike for him. I test rode it down the street and back, and while going through the gears, the front derailleur just came apart while I was shifting into the tall sprocket. Now I understand why nobody wants a Walmart bike. It's long out of warranty so I need to find a front derailleur. I also need some instructions on how the cable is ran and connected, this one looks weird. Any help?

can't help you, but i would like to comment about walmart bikes. the experiences that people have with them seem to be varied. some people have horror stories but some people seem to get a bike with no problems from walmart. i think when you buy a more expensive bike what you are buying is a guarantee of having no headaches down the road with the bike.

If its for a kid down the street, I'll bet he'd be happy with the bike even if it didn't have a front shifter. Maybe give him the bike, and he can save for the front shifter if he really wants it. If you really want to put one on it, there are some inexpensive ones available online:

http://www.nashbar.com/results.cfm?s...t%20Derailleur

Cables for a 'generic' bicycle can be bought fairly cheap at your local sporting goods store that sells bicycles. I buy them at my local Sports Authority store as a packaged set for the entire bike (brakes and shifters) for less than $10. I wasn't using the front derailleur on mine commuter so I just took it off since it was pretty rusted out.

How you route them will depend on if there are braze-ons on the frame. They usually run through a housing/tube to a braze-on up near the top of the downtube, then under the downtube to the BB (exposed), then go through a rubber housing/sleeve up to the derailleur. The 'generic' cables usually have enough tubing so you can replace whats lost or damaged, or you can just use the cable in the housing and zip tie it to the frame.

Remove the cable and derailer, then put the chain on the middle ring, and you will have a seven speed the kid can beat on.

When the FD on my Huffy froze, I just removed it. If I really need to shift, I can just pull over and manually put the chain on the appropriate ring.

Go to a bike shop and they'll have a used FD for about ten bucks. They may even throw it on for you.

I appreciate all of the suggestions but I never could do anything 1/2 AS#. If something doesn't work the way it's suppose to, I have to make it work the way it's suppose to. My only problem is I don't know how to select a generic or brand name replacement front derailleur if it's not OEM. The original front derailleur is a Shimano Top Swing 515. I guess it must be exclusive to the Wal-Mart Schwinn Aluminum Comp.

Don't have a LBS.

That's the good thing about bikes. You don't buy parts by year/make/model like cars or appliances, but by, in this case, clamp size and pivot swing.

In that case, remove the front derailer and cable, remove its shift lever. Take off the crank, and drill out the rivets for the small and large sprokets; leaving just the middle one. Now its no longer a bike with 2 unusable front sprokets, but a bike Intended for using only 1 in front. Some cross bikes run with only a rear derailer...
Thats the nice thing about bikes, infinitely customizable for personal prefs with no absolute right or wrong answer.

"...original front derailleur is a Shimano Top Swing 515"
That's SIS

Just take the FDER to the bike shop and ask for a cheap one that'll replace it. Should be <$10 and still be an "upgrade".

Nice work, xeno. I like this answer a lot. I've been telling people for years to ignore the pro advice about right and wrong and set the bike up so it works for you and for what you want to do. About 10 percent of them listen.

Good thing about cheap bikes is you can get a donor pretty cheap. Any pictures of what you are dealing with?