Hot Tip of the Month - April 2010: “Wobbling chainwheel on the Star Trac NXT”

If your NXT produces a ride that feels like a oscillation between a tight chain and a loose chain, check the chain wheel. The chain wheel is the sprocket that’s attached to the crank arm on the drive side of the bike. If you engage the drive train and it looks like the chain wheel is turning in an uneven motion like a bent bicycle wheel, you may have a fractured bottom bracket spindle. This happens when the end of the bottom bracket spindle cracks or fractures and the crank bolt is still holding the bottom bracket and crank assembly in tact. Dis-assemble the outer chain guard and remove the crank to see if this IS the case. If the spindle is not fractured, you make have a bad spindle or the chain wheel may be distorted.

Return to Hot Tips