BottomBraket
January 1st, 2009, 12:48 PM
New Solution to Old Shifter Problems
OK, the solution may not be new, but it’s new to me.
The Old Shifter Problem
I’ve worked on three olds bikes lately, all more than 10 years old and likely underutilized. They all had the same index-shifter problem. They would shift from the smallest rear cog to the first few larger cogs, but then the shifter failed to catch and pull the shift cable any further. Thus, the lowest 3 to 5 gears were not engaging. Front index-shifting had similar problems, not all three rings were available.
Background
Index shifters are similar to old Swiss watches. To function properly, they utilize a series of springs, levers, gears, ratchets, pulleys, and other mechanisms.
The Investigation
Upon inspection of the shifters, I notice substantial old dry stiff decaying grease within the shifting mechanisms- springs, levers, gears, ratchets, pulleys, etc. The dry stiff grease prevented the spring from pulling the ratchet back into the gear teeth of the shifter mechanism. Thus the shift lever had nothing to pull.
The New Solution
1. Take the covers off of the shifter. This step maybe optional but I always take the covers off.
2. Remove the shifters from the handle bar. I just leave the shift cables on.
3. Soak both the front and rear shifters in your favorite solvent. I use gasoline in a coffee can, its cheap, available, and an excellent solvent. I like to let it sit overnight but 2-4 hours seems to work.
4. Use a toothbrush to dislodge any stubborn grease. Then rinse the shifters in clean solvent.
5. Let the solvent dry.
6. Lube the shifting mechanism with a very light weight lube. I use ProLink chain lube.
7. Test the shifters to ensure that the ratchet catches all available gears. If not, work the ratchet back and forth so that it moves freely. If it’s still not working, try more cleaning and lubing.
8. Installing new cables is likely optional.
9. Reassemble the shifters and go ride.
Caveat
This procedure is NOT for the faint of heart. Index shifters are extremely delicate. Permanent unrepairable shifter damage may occur during the procedure.
OK, the solution may not be new, but it’s new to me.
The Old Shifter Problem
I’ve worked on three olds bikes lately, all more than 10 years old and likely underutilized. They all had the same index-shifter problem. They would shift from the smallest rear cog to the first few larger cogs, but then the shifter failed to catch and pull the shift cable any further. Thus, the lowest 3 to 5 gears were not engaging. Front index-shifting had similar problems, not all three rings were available.
Background
Index shifters are similar to old Swiss watches. To function properly, they utilize a series of springs, levers, gears, ratchets, pulleys, and other mechanisms.
The Investigation
Upon inspection of the shifters, I notice substantial old dry stiff decaying grease within the shifting mechanisms- springs, levers, gears, ratchets, pulleys, etc. The dry stiff grease prevented the spring from pulling the ratchet back into the gear teeth of the shifter mechanism. Thus the shift lever had nothing to pull.
The New Solution
1. Take the covers off of the shifter. This step maybe optional but I always take the covers off.
2. Remove the shifters from the handle bar. I just leave the shift cables on.
3. Soak both the front and rear shifters in your favorite solvent. I use gasoline in a coffee can, its cheap, available, and an excellent solvent. I like to let it sit overnight but 2-4 hours seems to work.
4. Use a toothbrush to dislodge any stubborn grease. Then rinse the shifters in clean solvent.
5. Let the solvent dry.
6. Lube the shifting mechanism with a very light weight lube. I use ProLink chain lube.
7. Test the shifters to ensure that the ratchet catches all available gears. If not, work the ratchet back and forth so that it moves freely. If it’s still not working, try more cleaning and lubing.
8. Installing new cables is likely optional.
9. Reassemble the shifters and go ride.
Caveat
This procedure is NOT for the faint of heart. Index shifters are extremely delicate. Permanent unrepairable shifter damage may occur during the procedure.