Bicycle Mechanics - Front Derailleur Shifts too quickly into 3rd Chainring

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JeffC
06-13-08, 07:29 AM
I've got 3 chainrings and SRAM grip shifters. On the shifter itself there are the numbers "1", "2" and "3" corresponding to the three rings and an orange bar that moves when you shift and points to the chainring you are in. There is about an inch of space between the three numbers. There is no problem shifting between each chainring and the gears run pretty quietly in all three chainrings with no obvious rubbing. However, when shifting into the biggest chainring, that is #3, the orange bar on the shifter only moves about halfway from the "2" to the "3" before it shifts and then the grip shifter will not move any further. Otherwise though, the bike still runs fine on the 3rd chainring.

In contrast when shifting from the 1st to the 2nd chainring, I have to shift all the way (not just halfway) to the "2" on the shifter to complete the shift.

Any idea on what causes this, how to fix it if I should, and if it may lead to problems? I cannot seem to find any discussion on this. I think I may need to loosen the barrel adjuster on it but am not certain. If you all have any ideas, I'd appreciate it.


SpeedingTicket
06-13-08, 08:20 AM
It has to do with setting the tension. If the chain falls off if you try to go to 3, then you need to set the limiters too.

This article covers just about everything
http://www.sheldonbrown.com/derailer-adjustment.html