One of our chronic problem customers has been destroying front derailleurs at a rate of about one a month since April. The first one was simply old. It had been on his bike since about 2005. He rides a lot and, judging by the look of the bike, without finesse. But something more persistent seems to plague him.
This bike was supposed to be his fresh start after he beat his old hybrid into the ground. It's a Fuji Roubaix, a moderately decent road bike. He's had to replace wheels. He trashed a carbon fork. He was plagued by flat tires for the longest time. He's had shifting problems. As annoying as the endless series of mishaps and accelerated wear and tear has been, we could generally find cause for effect. Until the Plague of Front Derailleurs, that is.
By the end of yesterday, an hour after closing time, I had looked up the Rite of Exorcism on line. I'd thrown everything else at the bike. I was ready to dump some major Latin on it. Then I saw it was 15 pages. Fun's fun, but that's a lot of
"...aut saltem corde peccata sua detestans, peracto,
si commode fieri possit, Sanctissimo Missæ sacrificio,
divinoque auxilio piis precibus implorato, superpelliceo
et stola violacea indutus, et coram se habens obsessum
ligatum, si sit periculum, eum, se et astantes communiat
signo crucis, et aspergat aqua benedicta, et genibus
flexis, aliis respondentibus, dicat Litanias ordinarias
usque ad Preces exclusive..." And so on.
At least we finally got to see what he's doing to mangle his derailleurs in his own unique way. The first one had broken at the front of the cage so it could not push the chain effectively. The second one went the same way, but also had the outer plate of the derailleur cage peculiarly bowed outward. The third and fourth derailleur have also had that peculiar outward bend to the outer cage plate.
The rider had neglected to mention, and the bike had failed to show us on any test ride until yesterday, that the chain was hanging up on the outer chainring when downshifting under load (his standard MO, apparently) and getting dragged up into the derailleur. Each incident progressively spreads the cage more and more until the bike will barely shift.
But here's the kicker. We have now changed absolutely every component involved: front derailleur, chain rings, chain, bottom bracket bearings, everything. All brand new. Chain still jams.
ADJÚRO ergo te, omnis immundíssime spíritus, omne phantásma, omnis
I might just resort to the Holy Sledge Hammer and call it good.