Technical > Transmission

Thorn Raven bottom bracket creaking

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taylor529:
The bottom bracket on my Thorn Raven has suddenly started creaking.  I have tightened both crankshaft bolts to ensure that that is not the source of the noise.  I have tightened the eccentric securing bolt,  my first suspects as these have come loose on me in the past.  I have checked that allthe spider nut and bolt sets securing the chainring are tight and still I get a loud creak every time that I push down the left foot on the pedal.  I even tried repositioning the eccentric and fixing it at a slightly different chain tension.  What could be causing the creak.  I have barely done ten thousand kilometres on this outfit?

blair:
Have you seen the topic "RST - Plauged with noise" in the Rohloff Internal Hub Gears forum?
http://www.thorncycles.co.uk/forums/index.php?topic=1384.0

(ps - anyone know to do a cross-post in a more civilised fashion?)

geocycle:
taylor529 you have my sympathy!  It's the most annoying of bike ailments.  In my case the holes made by the retaining bolts on the EBB had coalesced.  My problem was solved by completely removing and repositioning the EBB and applying lots of grease to the BB shell and the cranks.  Could you have some corrosion perhaps?

taylor529:
The creaking has been banished.  Thanks for the help.  I borrowed a crank puller and removed the left crank.  I slackened the EBB set screws, slackened and removed the chain.  The set screws were then completely removed and the EBB eccentric shell just dropped out complete with bottom bracket.  I found numerous pits in the aluminium shell from the various times at which I had adjusted the chain.  I also found two long scores from the time that the EBB had come loose 6 months ago while riding.  All these indentations had raised rims of metal which I filed flush with the surface and polished with emery paper.  The surfaces and all the threads were smeared with Loctite nickel anti-seizure grease and everything reassembled.  No Creak!

geocycle:
Good news!  Glad you've got rid of the creak.  My EBB also has some deep score marks from when I tried (unsuccesfully) to remove the BB itself.  I even bought a replacement EBB but have not needed to fit it as the noise was banished.

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