I lost the ability to shift chainrings last night. Upon pre-inspection cleansing the wee plastic cover popped off the spring, which spins freely. The short end has a slightly snapped-off look about it when peered at intently. As it's a riveted-together inexpensive Sora I assume I'll be required to replace the entire thing?
CityCyclingEdinburgh Forum » Questions/Support/Help
front mech spring sprung
(11 posts)- Started 13 years ago by wingpig
- Latest reply from wingpig
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Posted 13 years ago #
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Hmm. Hiding in the muck on the dust sheet was this:
...which I assume to be the bit which one end of the spring should be braced against. Bums.Posted 13 years ago # -
This very thing happened to my tiagra front mech a fortnight ago - it's terminal and quite common according to chaps in The Bicycle Works. I had always assumed front mechs lasted forever - apparently not!
Posted 13 years ago # -
If the replacement lasts another almost-exactly-six years it'll be worth the relatively low cost even though I don't use the front mech too often. I wondered if the wee bit might have been gluable/clampable back into place for use on another 31.8mm-seat-tubèd frame but when I removed the mech in order to make way for the replacement the fixing-band bent and almost snapped...
Posted 13 years ago # -
Wingpig you did well to get six years out of a Sora front mech. The one on my winter bike snapped after about three, while passing a van in Prestonpans. I have its replacement in the shed somewhere but iirc they're only about £8. I use a Campagnolo Centaur one now which, as Bicycleworks pointed out to me "shouldn't work but does".
Posted 13 years ago # -
My Sora is 7 years and still going stong. I think it's old enough to have been made out of "proper metal". I have lost the sticker to the ravages of time and degreaser though.
Posted 13 years ago # -
kaputnik, you must've got lucky. Mine was made of cheesium.
Posted 13 years ago # -
to be fair to the production quality of Sora, it pretty much sat unused, being cursed as a wasted investment, for about 4 years!
Posted 13 years ago # -
My replacement cannot be emplaced until I fit a thinner tyre. That indentation on the back of the band (doubtless the cause of the weakness) allowed me to creep up to 28C as it deepened. New band I'd both unindented and thicker to begin with.
Posted 13 years ago # -
Crikey you can pick up a new Sora front derailer for £14 online, 6 years seems like good going.
You know you could use the existing vertical Clamp Band Unit to save buying a smaller new tyre!?!? just take the new one off the new derailer:
Shimano Sora 330 Exploded Schematic
This is an example but all models are listed here:
Posted 13 years ago # -
The old unit's band is now bent and even more weakened than it already was (pictured above) so won't be getting refitted in case it decides to snap (and simultaneously stab the tyre, jab my leg, haul the chain to a halt, rip off the downtube-mounted cable-things and drag the handlebar sharply leftwards as the cable tightens). Alternatives (such as finding a smaller biggest chainring (so that the band can be fitted further down the seat tube)) have been considered and rejected; slightly smaller rear tyre is the easiest as I have spare smaller-(and-more-worn)-than-currently-fitted tyres I can re-fit to check. Not-yet-fully-evaluated alternatives would include finding a different mechanism which naturally sits much lower down the tube or which has a thinner band.
Posted 13 years ago #
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