EBB help - please.....

[Peejay]

Hi Everyone,
                   I have a Raven with Thorn's own 5-arm crankset - splined LH crank. The dreaded creak every revolution of the pedals has started and I'm planning to check everything out including stripping and re-greasing the EBB this weekend.

Does anyone know the tightening torque for the external bearings in the BB eccentric?

Also is it best to remove/refit the external bearings with the BB eccentric still in the frame with the EBB screws tightened to stop it rotating, or should I fit them with the BB eccentric out of the frame and held in a vise?

Are the Thorn external bearings LH and RH threaded like the Shimano ones.

Thanks,

Pete.

[geocycle]

Ah, yes been there!  Start with the easy bits and I suggest working outside in.  Check pedals (remove, grease and tighten), if possible try and pedal with one leg to isolate the noise.  If still no joy remove cranks, grease and refit (some folk argue against greasing). Then remove EBB and grease, check for channel marks where the bolts have slipped.  Finally if still no joy try removing the BB.  I'd advise against trying to do this in the frame as there is a risk of it moving and scoring the EBB, but it can work.  External BBs would be easier I guess.

Good luck, (you'll probably discover it is the saddle...)!

[JimK]

10-17 Newton-meter is the spec for the torque on the EBB bolts - see p. 9 of

http://www.thorncycles.co.uk/thornpdf/ThornBikeOwnerManual2Web.pdf

The most recently such annoying sound turned out to be a pedal on my bike. I just swapped in a new pair of pedals and the sound went away. The new pedals were around $15 on ebay and I am still using them! Lucky me, the problem was easy to find and fix.

I have definitely had a similar sound emanating from the saddle. Then it was the bolt that fasten the rails to the seatpost. They were reasonably tight but when I sat on the saddle things shifted and loosened up just enough. That was on my Legnano in 1976. Took maybe 6 weeks of fiddling to figure it out!

[Peejay]

Hi Jim,
          As ever - a big thanks...

It's the torque for external bearings into the eccentric I need please.

I'm OK with the eccentirc securing bolts under the bracket shell.

Pete.

[JimK]

oops, sorry for my lazy reading!

I have an old-fashioned internal type bottom bracket on my bike & no experience with such things anyway.

Best of luck with your hunt!

[Danneaux]

Hi Pete!

Shimano recommendations for Hollowtech II EBB cup torque are published as 34.5~49.1 Nm (35-50Nm in some of their inserts) /or/ 305~435 in-lbs.If you have a ft/lb torque wrench, this is 25.4-36.25 ft-lb.

See: http://bike.shimano.com/publish/content/global_cycle/en/sg/index/tech_support/tech_tips.download.-Par50rparsys-0003-downloadFile.html/Hollowtech%20II%20Crank%20Installation.pdf

Hope this helps.

Best,

Dan.