Diagnosing a clunk when power applied to the pedals (I have tightened what I can)
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Diagnosing a clunk when power applied to the pedals (I have tightened what I can)
Ok, so this is probably the worst sort of thing to diagnose via text, but bear with me.
Bike is a Trek Crossrip elite. Had a few hundred hard gravel miles, now is a relaxed commuter. Chain is new, chainrings and cassette are original (FSA and an SRAM 9-speed). Wheels are not original (WTB SX19's on x7 hubs), but the cassette is on nice and tight and the skewers
Pedals are tight, no play in BB. Headset is adjusted well, bars, levers, and interrupter levers are tight. Seat collar is tight (possibly the seatpost needs grease, it is on my list).
When I apply power, most usually from a stop, and more typically the left pedal but also at times the right (I usually go through a half spin with my right leg and then stand on my left), there is a slight "clunk" sound - as if something mechanical slips. Sort of like the sound you'd expect if something that spins is not tight (cassette lockring, crank arm bolt, etc) As far as I can tell, it all is, and I've had another pair of eyes go over and check bolts. There is a rack on the bike, and it could be some weirdness there if the seat stays are flexing, but I don't really think the seat stays are made to flex much on this frame.
Once I'm moving and applying only moderate power I don't hear it - it is only a stand and climb or grab the bars and mash sort of thing, and not on every stroke or even every fifth stroke.
What might cause something like this? Does the BB need to be lubed?
Bike is a Trek Crossrip elite. Had a few hundred hard gravel miles, now is a relaxed commuter. Chain is new, chainrings and cassette are original (FSA and an SRAM 9-speed). Wheels are not original (WTB SX19's on x7 hubs), but the cassette is on nice and tight and the skewers
Pedals are tight, no play in BB. Headset is adjusted well, bars, levers, and interrupter levers are tight. Seat collar is tight (possibly the seatpost needs grease, it is on my list).
When I apply power, most usually from a stop, and more typically the left pedal but also at times the right (I usually go through a half spin with my right leg and then stand on my left), there is a slight "clunk" sound - as if something mechanical slips. Sort of like the sound you'd expect if something that spins is not tight (cassette lockring, crank arm bolt, etc) As far as I can tell, it all is, and I've had another pair of eyes go over and check bolts. There is a rack on the bike, and it could be some weirdness there if the seat stays are flexing, but I don't really think the seat stays are made to flex much on this frame.
Once I'm moving and applying only moderate power I don't hear it - it is only a stand and climb or grab the bars and mash sort of thing, and not on every stroke or even every fifth stroke.
What might cause something like this? Does the BB need to be lubed?
#2
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Your right , Find a shop to see it. which cannot be done ,Here.
<guess> Freehub Pawls may just be engaging Late, because the grease is cold its delayed a little.
<guess> Freehub Pawls may just be engaging Late, because the grease is cold its delayed a little.
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It is possible for a bearing or press fit to feel tight with hand pressure but show "looseness" under the far greater pressures of pedaling. Andy.
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Bottom Bracket Cups/Retaining Rings Loose?
Turn the cranks so that the left crank is alongside the seat tube, wrap both hands around the crank and seat tube and squeeze the crank hard toward the seat tube.
Then turn the cranks so that the right crank is alongside the seat tube and repeat this. Listen for a creak/click.
Turn the cranks so that the left crank is alongside the seat tube, wrap both hands around the crank and seat tube and squeeze the crank hard toward the seat tube.
Then turn the cranks so that the right crank is alongside the seat tube and repeat this. Listen for a creak/click.
Oh well, an excuse to buy a few more tools is never a bad thing!
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New chain skipping on the most worn cassette sprocket when under heavy load (i.e standing start after a stop, mashing out of saddle, etc.) ?
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Brad
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I've had clunks from:
- Cheap plastic platform pedals. Wear had ovaled out the plastic around the bearing, letting the bearing move around.
- New chain skipping on worn cassette.
- Loose cassette lockring.
- Cheap plastic platform pedals. Wear had ovaled out the plastic around the bearing, letting the bearing move around.
- New chain skipping on worn cassette.
- Loose cassette lockring.
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Cleats maybe? It could also be somewhere else on the bike but related to torque from the pedals. A good mechanic could tell you what it's not at least.
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So, the noise existed before the chain replacement. Cassette lockring is tight (rechecked). Pedals are shimano a-530's, used with sneakers (not clipless, and on the platform side obviously). Cassette isn't looking terribly worn (about what you'd expect in 1500 miles with regular cleaning), and the noise sounds like something slipping, maybe, but I don't feel the pedal or chain slip - the noise is more subtle than that, too.
I can make it make something like the noise if I squeeze the crank against the seattube then spin the cranks and squeeze the other against the seattube. I don't have the tools to pull apart the BB, so I'm going to visit my LBS today or tomorrow. I don't mind throwing a few dollars at it, I guess. I hate undiagnosed noises.
I'm sure Trek just put the cheapest BB they could find in this bike, and it probably wasn't properly tightened, to boot.
Last edited by ph0rk; 03-24-16 at 07:56 AM.
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So, the noise existed before the chain replacement. Cassette lockring is tight (rechecked). Pedals are shimano a-530's, used with sneakers (not clipless, and on the platform side obviously). Cassette isn't looking terribly worn (about what you'd expect in 1500 miles with regular cleaning), and the noise sounds like something slipping, maybe, but I don't feel the pedal or chain slip - the noise is more subtle than that, too.
I can make it make something like the noise if I squeeze the crank against the seattube then spin the cranks and squeeze the other against the seattube. I don't have the tools to pull apart the BB, so I'm going to visit my LBS today or tomorrow. I don't mind throwing a few dollars at it, I guess. I hate undiagnosed noises.
I'm sure Trek just put the cheapest BB they could find in this bike, and it probably wasn't properly tightened, to boot.
I can make it make something like the noise if I squeeze the crank against the seattube then spin the cranks and squeeze the other against the seattube. I don't have the tools to pull apart the BB, so I'm going to visit my LBS today or tomorrow. I don't mind throwing a few dollars at it, I guess. I hate undiagnosed noises.
I'm sure Trek just put the cheapest BB they could find in this bike, and it probably wasn't properly tightened, to boot.
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It's a "clunk", not a click, or a creak?
Are those FSA cranks, with the two bolts on the non-drive arm? I used to get a clicking noise on my old bike. I had to remove the crank arm, wipe the splines clean, grease the splines, and reassemble.
I used teflon tape on the Mega Exo external bottom bracket threads.
On my new bike, I was sure that the bottom bracket PF30 was creaking. It was intermittent, usually happening when standing or starting off fast. But it's the rear skewer. I had to clean and lube the skewer pivots, and clamp it a little tighter. That fixed it. (But it comes back occasionally if I'm not careful about clamping it.)
Are those FSA cranks, with the two bolts on the non-drive arm? I used to get a clicking noise on my old bike. I had to remove the crank arm, wipe the splines clean, grease the splines, and reassemble.
I used teflon tape on the Mega Exo external bottom bracket threads.
On my new bike, I was sure that the bottom bracket PF30 was creaking. It was intermittent, usually happening when standing or starting off fast. But it's the rear skewer. I had to clean and lube the skewer pivots, and clamp it a little tighter. That fixed it. (But it comes back occasionally if I'm not careful about clamping it.)
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It's a "clunk", not a click, or a creak?
Are those FSA cranks, with the two bolts on the non-drive arm? I used to get a clicking noise on my old bike. I had to remove the crank arm, wipe the splines clean, grease the splines, and reassemble.
I used teflon tape on the Mega Exo external bottom bracket threads.
On my new bike, I was sure that the bottom bracket PF30 was creaking. It was intermittent, usually happening when standing or starting off fast. But it's the rear skewer. I had to clean and lube the skewer pivots, and clamp it a little tighter. That fixed it. (But it comes back occasionally if I'm not careful about clamping it.)
Are those FSA cranks, with the two bolts on the non-drive arm? I used to get a clicking noise on my old bike. I had to remove the crank arm, wipe the splines clean, grease the splines, and reassemble.
I used teflon tape on the Mega Exo external bottom bracket threads.
On my new bike, I was sure that the bottom bracket PF30 was creaking. It was intermittent, usually happening when standing or starting off fast. But it's the rear skewer. I had to clean and lube the skewer pivots, and clamp it a little tighter. That fixed it. (But it comes back occasionally if I'm not careful about clamping it.)
I have actually tried a second wheelset in this bike(!), pretty certain that wasn't it. I could localize the 'pulse' with my feet, it alternated sides of the BB - hard to put into words. Post grease and tighten was a pretty big difference - the bike felt stiffer and more responsive when standing and mashing in a way I didn't even notice I was missing.
I figure the grease and retighten should do for a while, with any luck long enough for me to be antsy to try a different groupset (ditching the FSA components in the process - Tiagra 4700 most likely). AFAIK I'd need a new BB as the current BB is square taper.
#13
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I had something like this happen once and it was diagnosed as being something to do with the rear hub. I wasn't mechanically minded at the time, so I left it to the mechanic and didn't pay much attention to the details. My advice is take it to a bike mechanic... there's no point driving yourself nuts over it.
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I've had it from a crank that wasn't tightened quite enough. Make sure they're torqued correctly (that is, really tight!).