Old Front Derailleur

[reoterq]

I bought a used bike the other day - nothing special - a dual suspension mongoose appx 1998-2000 vintage (I'm an old runner looking to get into biking due to less impact on the joints). Anyway, the rear gears shift fine, but the front derailleur is very hard to move with direct pressure from my fingers, much less using the handlebar shifter (which won't move at all). I disassembled the shifter and verified that it will move just fine, along with the cabling system. The spring on the derailleur is rusted, and I'm guessing that extra friction is the cause of my trouble. Am I on the right track, and is there a way to "loosen it up" so I don't have to buy new parts for an economical starter bike? Thanks.

 

[alfeng]

I bought a used bike the other day - nothing special - a dual suspension mongoose appx 1998-2000 vintage (I'm an old runner looking to get into biking due to less impact on the joints). Anyway, the rear gears shift fine, but the front derailleur is very hard to move with direct pressure from my fingers, much less using the handlebar shifter (which won't move at all). I disassembled the shifter and verified that it will move just fine, along with the cabling system. The spring on the derailleur is rusted, and I'm guessing that extra friction is the cause of my trouble. Am I on the right track, and is there a way to "loosen it up" so I don't have to buy new parts for an economical starter bike? Thanks.

YES, you can "loosen it up" ... I was once given a front derailleur which was hopelessly FROZEN -- here's what I did & how you can deal with it:

• Put a couple of drops of 3-in-1/household oil on the front derailleur's pivots ... wait a few days ... try to move the derailleur ... put a few more drops on ... continue to REPEAT every few days ...
• Depending on the amount of rust, the derailleur will be functional within a week ...
• Once the derailleur is functional, you want to "flush" the residual rust away from the pivots ... more oil & motion + more oil & motion ... until the oil that is on a paper towel (which is used to absorb the excess") runs (relatively) clean.

While the rust on the springs, themselves, is problematic ... it is mostly cosmetic (IMO) UNLESS the rust has significantly eaten away at the spring's diameter (unlikely) -- if anything, the rusting on the spring will give the front derailleur a LIGHTER action! Oil/grease the spring to preclude further rusting.

BTW. This is probably easier to do with the derailleur OFF of the bike, but you can certainly leave it on the bike if you want.

 

[kdelong]

You can pick up a good replacement on eBay for $10.00. No fuss, no muss!