Giant ATX 870 bike – Shimano STX RC front derailleur stuck permanently [WD-40 success story]

My old Giant ATX 870 bike seems to run nicely, with some glitches here and there maybe but no larger issues.

So far, I replaced the grip shifter (due to gooey plastic, UV / sunlight), a few times all cables (normal service thing that one can do for one’s bike), and surely the tubes and tires whenever it seemed necessary. After a winter 2020/21, where I was out and about on spike tires and really salty roads, the degree of corrosion may have been higher than in other years because all of a sudden, my front derailleur got terminally stuck. It was fixed set stuck on the largest chain wheel and did not move a bit towards the middle leave alone smallest chain wheel. So. what to do?

Again, the internet saved me: I found that some real bike users identified WD-40 as “the solution”, literally and proverbially, to the predicament of a stuck derailleur. However, I applied WD-40 a few times at first and no success.

I then figured that I was not using WD-40 the right way to get the derailleur to move again. Also I figured that the people that had disassembled and reassembled the derailleur with little success may have missed the aspect that the parts still should have been soaked in WD-40 for a few days.

So I left all parts in place, did not disassemble a thing, and performed about 15-20 cycles of this sequence:

  1. I sprayed WD-40 into all joints of the derailleur
  2. I waited a minute or two
  3. I applied substantial forces to get it to move just a bit, trying to mobilize it, pressing hard against it but not hammering and not using any wrench or so, just firm manual pressure, and after that
  4. back to step 1

Every night I made sure the derailleur did not have to spend the night without having its joints soaked in WD-40. At first, step 3 only made the derailleur move a few millimeters. After a few more cycles of that, it went a few more millimeters. Later it would move with pressure but not by itself (with the built-in spring) so I kept at it. Now, the spring does its service again and the front derailleur shifts smooth as silk. Total WD-40 used was an estimated 150 ml, but I always tried to apply it rather precisely to the joints, and only a small amount at a time, then giving the WD-40 time to exert its effect onto the corroded and old surfaces of the derailleur joints.

And, lo and behold, after ~4-5 days of that treatment with many cycles of the steps outlined above, all of my shifters now are back to a supple function that feels perfect – but most importantly the stuck derailleur. Why buy a new component when the old one can rise from the dead by use of WD-40.

I also did not disassemble and reassemble it, as the chemistry of WD-40 with its effect over repeated applications seemed to have done the trick without any parts drama.

More details of this bike here [LINK].

Front derailleur stuck Shimano STX-RC Umwerfer klemmt blockiert Giant ATX 870 #wd40 #oldbike #mountainbike #repairbike #fixbike #veloreparatur #patience #geduld

Cite this article:
Wolf Schweitzer: - Giant ATX 870 bike – Shimano STX RC front derailleur stuck permanently [WD-40 success story]; published 03/04/2021, 09:17; URL:

BibTeX: @MISC{schweitzer_wolf_1638355741, author = {Wolf Schweitzer}, title = {{ - Giant ATX 870 bike – Shimano STX RC front derailleur stuck permanently [WD-40 success story]}}, month = {April}, year = {2021}, url = {} }