Yesterday my chain came of the gear wheels 3 times. Pity me , I think my gear changing techinique may be foolish and clumsy, eg, changing boths sets at the same time/keeping my finger on the lever for too long. What causes bike chain slippage?
bad adjustment of the rear derailleur position and / or tension. Adjust cable tension: derailleur dolly wheel should be dead vertical and in line with the cassette sprocket when seen from behind, at each gear position.
mixed manufacturer gear components: Derailleur is neutral enough (assuming the correct cable draw versus angle change) but the shifter handle range (i.e., ten “speeds” or 8 speeds) should match the number of gears you have on the cassette. Don’t mix SRAM and newer Shimano and any Campagnolo: they’re too dependent on precise and exact tolerances to each otehr and will shift badly or not at all with mixed sets. (SRAM and older shimano work OK)…
incomplete throw of the front derailleur: adjust your technique, or adjust your limit stops on the derailleur pivot arm
sticking cable sheaths: replace cables and sheathes, or clean out (use a solvent or even WD40 applied to the cable outer using the red nozzle thingie until it drains out the other end) and re-lube with a dry lube (graphite powder works best) if not too worn.
worn chain/rings/cassette or all three. Replace (if a cassette and chain are old they will wear into each other, and thus BOTH need replacement). If you replace chains frequently, you don’t need to replace cassette each time. Crank rings normally go for 100,000 km before needing replacement, and sometimes more.
chain with a tight roller. Lube, and work free if just stuck from rust or dirt, or replace if not fixable (a bent roller pin will do that).
broken teeth on cassette sprockets or rings (rare). Replace.
bent derailleur hanger (following crash or transportation, this is very common). This needs delicate repair: usually replacement of a replaceable rear hanger if it’s aluminium or carbon frame, or bending back into alignment if its a steel frame. Aluminium non-removable hangers demand careful heat treatment to allow them to be bent back without snapping off or weakening the hanger, as aluminium work-hardens extremely quickly and breaks.
tbh I rarely change the front derailleur unless I’m going up big hills. If you bought the bike from a shop let them look at it.
oops, just saw a screw holding the derailleur was loose affecting the alignment- being a cyclist isn’t just about having pretty legs eh?
Thnx for the response.
Did you tighten the “loose” screw? The screws on the derailleurs are adjusting screws and are usually at different heights. Is the problem fixed? If not, could you provide more detailed information: drivetrain, mileage, condition, etc.
it’s fine - the bike is 2 months old and frankly I was suprised that I have had so much maintanence to do, how niave i was.