My son's just had the bike a couple of months. Occasionally the chain jumps off the front large chainring. Looking at it more closely I see there are several small teeth on this chainring. Is that the cause and why are they like that? Bike only gets light usage.
P.s. one pedal has just fallen off, ripping out the thread on the crank arm. My son only uses it for paperbound, so am a bit worried now about quality of this bike or am i unlucky and bought a badly made one. Are these parts guaranteed?