My drivetrain makes a really annoying and spooky popping sound when my driveside arm gets about 90* to the chain stay. Ive got a new freewheel, a slightly straight chainwheel, and a new chain can anyone help me?
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Anyt ype of suggestion or help would be muchly appreciated. Ive already torn it down once.
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Make sure your cranks and pedals are tight.
What do you mean by a "slightly straight chainwheel"? Does that mean it's mostly bent?
(锕侊箒)~~~~---------------------------------------------------------------------- Originally Posted by ProjectPat
My drivetrain makes a really annoying and spooky popping sound when my driveside arm gets about 90* to the chain stay. Ive got a new freewheel, a slightly straight chainwheel, and a new chain can anyone help me?
Single speed? If so, you have the chain tension too tight.
(锕侊箒)~~~~---------------------------------------------------------------------- Originally Posted by ProjectPat
... when my driveside arm gets about 90* to the chain stay. Ive got a new freewheel, a slightly straight chainwheel, and a new chain can anyone help me?
This problem is most likely related to the bottom bracket, crank arm or pedal. As Supcom mentioned, check the pedal to crank arm interface, and crank arm to bottom bracket interface. Check the bottom bracket too.
It could be a warped chain ring, especially if it only happens in either the biggest or smallest chainring. It could be the chain catching on the front der. Since the chainring is fixed with respect to the crank arm, it would satisfy the constant position criteria.
I dismiss the chain and rear der and cassette because it seems to occur at the same pedal stroke. (I assume the annoyance happens in the same crank arm position regardless of gear or the gearing is not 1:1).
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My money is on the bottom bracket. Take the chain off and see if the arms have any play in them. Then make sure the cranks spin smoothly. Generally, a scary sounding clunking like that comes from a BB that's about to fall out onto the sidewalk.
(锕侊箒)~~~~---------------------------------------------------------------------- Originally Posted by white lobster
My money is on the bottom bracket.
Same here. Last time I experienced this, it turned out that the BB wasn't tightened enough. I couldn't see any play by pulling on the cranks, but it sure went away when I tightened the BB.
(锕侊箒)~~~~---------------------------------------------------------------------- Originally Posted by ppc
Same here. Last time I experienced this, it turned out that the BB wasn't tightened enough. I couldn't see any play by pulling on the cranks, but it sure went away when I tightened the BB.
I don't have the torque specs for a bottom bracket handy, but it's probably more than one would expect.
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The recommended torque setting for a Shimano Octalink bottom bracket is 435 to 608 inch-pounds (50 - 70 NM) and for the crank bolts it's 305 to 435 inch-pounds (35 - 50 NM). This is REALLY TIGHT and a lot more force than you would ever use without a torque wrench unless you are very experienced.
Originally Posted by ProjectPat
My drivetrain makes a really annoying and spooky popping sound when my driveside arm gets about 90* to the chain stay. Ive got a new freewheel, a slightly straight chainwheel, and a new chain can anyone help me?
Single speed? If so, you have the chain tension too tight.
