Tarmac Expert 2011. Ultegra 6750 clicking.
08-29-14, 05:34 AM
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Tarmac Expert 2011. Ultegra 6750 clicking.
Hi everyone.
This is a "something's creaking" post but I have read/ investigated extensively and drawn a blank:
Bike: Specialized Tarmac SL3 Expert 2011 - Shimano Ultegra 6700 series throughout.
I experienced a pedal-stroke-frequency click on right hand side only when in the smaller chainring. I assumed the chainring bolts were loose. Drivetrain was due for a change; chain worn after ~6000 km so I replaced:
Chain, crankset (with compact 6750), pedals which were knackered and BB with new Ultegra sealed unit (just to be sure). For completeness I have a new cassette to install also.
I have also torqued carbon-carbon seatpost & tube correctly with assembly paste.
I have twisted the cable end out of the way so it is not that striking my shoe once per revolution.
The creak is still there and I have even given the bike a good wash and checked the BB shell for carbon-cracks; none obvious. But I am pretty vexed and I would be grateful to hear suggestions of how to diagnose further. There must be an expert out there!
Many thanks in advance.
This is a "something's creaking" post but I have read/ investigated extensively and drawn a blank:
Bike: Specialized Tarmac SL3 Expert 2011 - Shimano Ultegra 6700 series throughout.
I experienced a pedal-stroke-frequency click on right hand side only when in the smaller chainring. I assumed the chainring bolts were loose. Drivetrain was due for a change; chain worn after ~6000 km so I replaced:
Chain, crankset (with compact 6750), pedals which were knackered and BB with new Ultegra sealed unit (just to be sure). For completeness I have a new cassette to install also.
I have also torqued carbon-carbon seatpost & tube correctly with assembly paste.
I have twisted the cable end out of the way so it is not that striking my shoe once per revolution.
The creak is still there and I have even given the bike a good wash and checked the BB shell for carbon-cracks; none obvious. But I am pretty vexed and I would be grateful to hear suggestions of how to diagnose further. There must be an expert out there!
Many thanks in advance.
08-29-14, 12:28 PM
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Places to look.
Entire BB threads may be a bit sloppy in the frame. Unless super tight, this can allow some radial (vertical) movement between the BB and frame.
Pedal not quite tight enough. same issue as above, clean and grease crank faces threads and make sure pedals are tight.
Chainring lacks radial support on the arm. If the ring is supported entirely on the chainring bolts, without a tight fitting shoulder to take the radial load, the ring may creep around (precess) under chain load, creaking and eventually working the bolts loose.
These are the starters, but the list is long. Since the problem existed both before and after the changes, there's a good chance it's not in the BB at all, and might be something like axle flex synchronous to the pulsing chain tension.
You have to be a good diagnostician, and note the nature of the sound, and work through the possibilities separating the definite nos from the maybes, until you have a short list, then work that until you're down to one or none.
Entire BB threads may be a bit sloppy in the frame. Unless super tight, this can allow some radial (vertical) movement between the BB and frame.
Pedal not quite tight enough. same issue as above, clean and grease crank faces threads and make sure pedals are tight.
Chainring lacks radial support on the arm. If the ring is supported entirely on the chainring bolts, without a tight fitting shoulder to take the radial load, the ring may creep around (precess) under chain load, creaking and eventually working the bolts loose.
These are the starters, but the list is long. Since the problem existed both before and after the changes, there's a good chance it's not in the BB at all, and might be something like axle flex synchronous to the pulsing chain tension.
You have to be a good diagnostician, and note the nature of the sound, and work through the possibilities separating the definite nos from the maybes, until you have a short list, then work that until you're down to one or none.
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
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FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
08-29-14, 03:43 PM
#3
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Ok, I'm in for a solution.
I have a very similar problem. My click only occurs in the small chainring (34) while in lowest couple of rear gears.
I have a very similar problem. My click only occurs in the small chainring (34) while in lowest couple of rear gears.
08-29-14, 04:21 PM
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IME, climbing clicking (I assume that's why you're in the lower few gears) is often related to the high chain load. It could be a cassette that's not tightened enough, or rear axle flex, or the BB shifting back if there's any play there. OTOH everything flexes when climbing, so it could be bar/stem, headset, rear triangle and so on.
This is the hardest thing to diagnose because it only happens under load, and can be caused by just about anything.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Last edited by FBinNY; 08-29-14 at 04:28 PM.
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