Bicycle Mechanics - Front Deraileur karked it today

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View Full Version : Front Deraileur karked it today


NZLcyclist
08-22-03, 12:47 AM
Hi all,

Turned across traffic to the right today onto a street that has the biggest hill on my commute, went to change down on the chainrings (double), the shifter clicked a lil bit louder than normal (Sora) amd the DR proceeded to move slightly to the left and rub on the chain. I stopped, and had a look, the cable was slack like it should be abd the problem seems to be in the DR itself. There is no tension on it and it flops about. Like as though the spring has gone? havnt had a good look yet, but I had to force it into the small chainring, and then it was still floppy and it rubbed on the chain all 2km home. This combined with the fact that the cable for my rear DR needs replacing and I cant change there either meant I rode up this damn hill at 17kmh in a 39x21 with a loud rubbing noise, while heaving a big school bag..... i didnt dare stop for the red light! it was safe to keep going, no road on my side. grrr!

Brendon


Ed Holland
08-22-03, 03:20 AM
Bad luck NZL,

Yes it does sound like the spring has broken in the derralieur mechanism, but make sure that the shifter is still pulling the cable properly. How old is your bike- is it still under guarantee? If not, the good news is that a replacement FD is not expensive.

My bike is Sora too, and there have been a few problems with the front mech. At one point it seized and I had to completely dismantle it & re-lube to bring it back to life. It has also never been possible to adjust the system exactly right to prevent rubbing, but this is partly due to flexability in the frame and my love of mashing in high gears.

Hope you can get it sorted,

Cheers,

Ed

sch
08-22-03, 09:28 AM
It only takes 2-3min to take the derailleur off the bike and examine it closely to see if the cage return/load spring is broken. The spring is visible from the L side of the bike, it is a cylinder wrapped around the cage pivot with a straight
section a bit less than a cm. long at each end, one pushing on the cage and
the other on an eccentric on the casting arm the cage pivots on. If the cage
flops about that would rule out the most common scenario: a broken cable.
Steve


Chi
08-22-03, 09:51 AM
Upgrade time. :D

NZLcyclist
08-24-03, 02:15 AM
all fixed.

The lower bolt of the 2 holding the DR to the clamp on the frame had worked itself loose.

Brendon