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Right Crank, making stress cracking noise.

complience · 2005-07-31T19:30:57+00:00

My KHS 300 flite 2004. Came with the Sora Groupset. Last month i started using clippless pedals on it. But now when i strike hard down with my right leg at full power. There is a small sharp cracking sound, and i think i can feel vibration through the shoe. Its Very annoying, I think the source must a stress facture within the Crank itsself.. or the Front chain rings flexing under the pressure. Ive only been riding it for 4 months or so and done 4000k on it. Im not that heavy 10stone, also I do like to stand alot while pedaling. Ive tried Tighting every screw and bolt.. taken off the cranks and made sure they are firmly back in place on the bracket, and tried my old clipin pedals, nothing gets rid of the "crack" every time i pedal hard (which is just about 100% of the time) Are cracks forming within cranks very common on budget equipment like sora? I dont want to spend £30 on a new crank with chain rings.. if its not going to fix the problem.

Started by complience · 31 July 2005 · Last activity 8 August 2005 · 7 posts · 1,374 views

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01 / Original postRight Crank, making stress cracking noise.complience · 31 Jul 2005 02 / This pagePosts 1–7Page 1 of 1 · chronological order 03 / Latest replyPost #7oldbobcat · 8 Aug 2005

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Original section: Bike Cafe
Published: 31 July 2005
Last activity: 8 August 2005
Original author: complience
Posts: 7
Discussion status: Public discussion
Total views: 1,374
Views / 30 days: 4
Topics: Bottom brackets

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Original post
complience
Archived post

31 July 2005, 19:30 UTC #1

My KHS 300 flite 2004.
Came with the Sora Groupset.
Last month i started using clippless pedals on it.
But now when i strike hard down with my right leg at full power. There is a small sharp cracking sound, and i think i can feel vibration through the shoe.
Its Very annoying, I think the source must a stress facture within the Crank itsself.. or the Front chain rings flexing under the pressure.
Ive only been riding it for 4 months or so and done 4000k on it. Im not that heavy 10stone, also I do like to stand alot while pedaling.
Ive tried Tighting every screw and bolt.. taken off the cranks and made sure they are firmly back in place on the bracket, and tried my old clipin pedals, nothing gets rid of the "crack" every time i pedal hard (which is just about 100% of the time)
Are cracks forming within cranks very common on budget equipment like sora?
I dont want to spend £30 on a new crank with chain rings.. if its not going to fix the problem.

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imslayer
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31 July 2005, 20:19 UTC #2

that sucks i dont know what to say

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complience
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31 July 2005, 20:22 UTC #3

its making the Felt F55 ive got my eye on look all the more tempting.
http://www.awcycles.co.uk/products.php?plid=m1b226s6p7692

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oldbobcat
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8 August 2005, 04:21 UTC #4

complience said:
But now when i strike hard down with my right leg at full power. There is a small sharp cracking sound, and i think i can feel vibration through the shoe.

Everybody I know who has ever cracked a crank has said that failure was sudden. If there were warning signs, they were visible, not audible.
If you have an adjustable cups-and-cones bottom bracket, it sounds like your BB shell needs facing. Pro-quality shops that have the facing tools can do this. (Headsets should be similarly faced.)
If the facings are not perfectly square, then the the seating of the bearing cups distorts when the lockring is tightened down. The balls are now running under uneven tension in the bearing, a condition undetectable by just spinning the spindle unloaded. Under the torque, however, the balls will click as they squeeze past the tight side of the bearing.

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oldbobcat
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8 August 2005, 04:23 UTC #5

complience said:
its making the Felt F55 ive got my eye on look all the more tempting.

On the other hand, if you want to buy a new bike, that's OK, too.

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complience
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8 August 2005, 08:58 UTC #6

after a bit of investigation work ive found it is the bottom bracket.
Ive managed to temporary fix the problem. by just reversing the postions of the cranks.
However it clearly needs to be replaced.
is this a good buy?
http://www.chainreactioncycles.com/Models.aspx?ModelID=156

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oldbobcat
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8 August 2005, 20:22 UTC #7

complience said:
after a bit of investigation work ive found it is the bottom bracket.
Ive managed to temporary fix the problem. by just reversing the postions of the cranks.
However it clearly needs to be replaced.
is this a good buy?
http://www.chainreactioncycles.com/Models.aspx?ModelID=156

I haven't bought a BB in 25 years, so I wouldn't know. I'm in the States, so I'd guess that getting out from under for less than $40 is a pretty good deal. There isn't a lot of price cutting on BBs. If everything fits and the BB shell checks out, I'd say go for it.

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