How to Repair the Gear Changer on a Bike
It's now possible to buy bicycles with 24 and more speeds. There will be times you want to adjust or repair the gear changer on your bike. Dust and debris can slow down or damage the gear changer, or you may notice the gears don't shift as smoothly as they did when your bike was new. There are two ways you can repair the gear changer on your bike: adjusting cable tension and derailleur alignment.
Instructions
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Cable Tension Adjustment
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1
Inspect each shift lever, which you'll find on the handlebars, or on the frame on older bikes. Tighten any loose screws. This may be all you need to do to fix the problem.
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2
Locate the front derailleur on your bike--this is the mechanism the chain passes through. You'll find it on the frame, above the front gears. Locate the nut or bolt that holds the cable in place, and use an Allen wrench to loosen the nut or bolt.
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3
Pull the cable tight, using your hand. Don't use pliers because it will pull the cable too tightly. Continue to hold the cable tightly, and at the same time tighten the nut or bolt you had loosened in the previous step. This will hold the cable in its new, tighter position.
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4
Adjust the rear derailleur using the same procedure described above. Locate the rear derailleur on the frame below the rear gears.
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5
Go for a ride on your bike, switching through all the gears to see if they're changing smoothly. If it still doesn't feel right, you may need to fix the alignment of the derailleur.
Derailleur Alignment
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6
Ask an assistant to lift the rear wheel of your bike off the ground. Squat down next to your bike and slowly turn the pedals with your hand. Use the shift lever to rest the front derailleur at about the midpoint of its range.
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7
Find the two small screws located next to each other on the rear derailleur. If the problem is that the chain doesn't shift onto the biggest rear gear, then use a small Phillips screwdriver to turn the left, upper screw counterclockwise a quarter turn.
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8
Using your hand, continue to turn the pedals and shift through all the rear gears. If you find that the chain still doesn't go onto the biggest rear gear, move the chain back to the smallest rear gear. Now turn the right, lower adjustment screw as far as you can in a clockwise direction before you hear the chain rattle or click.
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9
Test the gears again by shifting through them. If needed, turn the left, upper screw counterclockwise another quarter turn.
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10
If the problem is that the chain doesn't shift onto the smallest rear gear, then use the Phillips screwdriver to turn the right, lower screw counterclockwise a quarter turn. Run a test by shifting through all the gears.
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11
Check to see if the chain will go onto the smallest rear gear. If it won't, then shift the chain to the biggest rear gear. Turn the left, upper adjustment screw as far as you can in a clockwise direction before you hear the chain rattle or click. Run a test by shifting through all the gears.
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12
Adjust the front derailleur following Steps 1 through 6 above. The front derailleur operates the same way as the rear derailleur. Adjust alignment using the two side-by-side screws located on the front derailleur.
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1
Tips & Warnings
The cables on your bike can wear out quickly. If this procedure doesn't fix the problems you have when shifting gears, take your bike to a professional.
Shifting problems may indicate worn out brake cables. Check out your brake cables immediately if you suspect a problem.
References
- Photo Credit bike image by Dubravko Grakalic from Fotolia.com
