Stiff (Tight) Chain Links

TIGHT LINK REPAIR
Tight links are typically the result of the two outer chain plates pushing tightly against the inner two chain plates. If pressure on the inner plates can be removed, the tight link can be fixed.
Some chain tools such as the Park Tool have a tight link repair system built into the tool. The following procedure demonstrates how to use the tight link repair system.
NOTE: Some nine-speed and ten-speed chains have narrow rollers and may not fit the tight link cradle. It will be necessary to loosen the tight link by hand, as described in below.

1. Locate the tight link. Put chain in smallest rear sprocket in back and on the middle ring of a triple crankset, or the smallest ring of a double crankset. This relieves tension on chain and makes problem links show up easier.
2. Back pedal slowly and watch chain as it passes through the two jockey wheels of the rear derailleur. Look for a popping or jumping of chain, or movement in derailleur arm. Keep backpedalling slowly. Tight link should show up as it passes by the tight bend of the lower jockey wheel.

3. Isolate tight link and move it to lower section of chain between chainring and rear cogs.
4. Engage tight rivet in tight link cradle.

5. Run chain tool pin up to tight pin and note position of handle.
6. Turn handle only one-eighth to one-quarter turn clockwise. This presses on rivet to spread chain.
7. Remove chain tool and feel tight link.
8. Repeat as necessary, pushing rivet from other side of chain.
9. Inspect chain rivet. Rivet must be centered in chain plates.

Tight Link Repair without Chain Tool
It is also possible to repair tight links without the tight link cradle system. This method requires physically stressing and flexing the chain laterally. Use care not to bend and deform the plates by using too much force. To avoid damaging your chain, practice on a section of scrap chain. Your hands are likely to get dirty from grabbing the chain. If this is a problem use a rag over the chain.
1. Locate the tight link as described above.
2. Grab either side of chain with your hands, and place both thumbs at the tight rivet.
3. Pull outward with your hands, while pressing inward with your thumbs to flex the tight link.
4. Reverse pressure to flex chain the opposite direction. Pressing inward with your hands and pressing outward with the index fingers centered on tight rivet.
5. Pivot link back and forth to see if it is free and repeat if necessary.