EBB - how tight?

[vik]

I got a Thorn Sterling frame yesterday...   This will be my first EBB bike.  How tight/deep do I need to make the pinch bolts to securely hold the EBB in place?  There was no documentation with my frame with instructions on how to do this and I didn't see any on the Thorn website.

Thanks,

Vik

[Pallium]

Vik,
Manual says 10-17 Newton meter, I think that this is too much. I used 10 Newton meter and the bolts went deep, I would suggest something like 8 Newton meter.
regards, Pallium

[vik]

Vik,
Manual says 10-17 Newton meter, I think that this is too much. I used 10 Newton meter and the bolts went deep, I would suggest something like 8 Newton meter.
regards, Pallium

Thanks - is there an online manual for the Thorn Rohloff bikes I can download?

[pdamm]

Vik

This page has a link to a Thorn bicycle owners manual

http://www.thorncycles.co.uk/downloads.html

Peter

[vik]

Vik

This page has a link to a Thorn bicycle owners manual

http://www.thorncycles.co.uk/downloads.html

Peter

Thanks very much Peter.  I've been to that page an managed to totally overlook that link previously.

cheers,

Vik

[julk]

I would stick with the Thorn recommended torque range, they make the bikes after all. The EBB is meant to have permanent dents made by the bolts.

I have seen it suggested that you should be slow to adjust the EBB when your chain slackens. Letting the chain get quite slack between adjustments allows you to move the EBB far enough to make a new set of dents with the bolts. This avoids the possibility of any dents joining up to make a groove which might result in EBB movement.

Whatever you do, avoid tightening the bolts into the thin part of the EBB. This will prevent any possibility of bolt damage to the bottom bracket bearing assembly.

[geocycle]

I agree with Julk.  The three things I've learnt about EBB are (i) don't be tempted to make fine adjustments -slack chains work fine until they fall off! (ii) keep the bolts nice and tight -there is a lot of metal in the thick part of the EBB for the bolts to bight into (iii) be careful adjusting the BB insitu - mine was very tight and the EBB rotated leaving a nasty gouge in the aluminium of the EBB.  I've removed mine twice to clean some minor rusting of the frame and to relube. 

[Dave Whittle Thorn Workshop]

I have seen it suggested that you should be slow to adjust the EBB when your chain slackens. Letting the chain get quite slack between adjustments allows you to move the EBB far enough to make a new set of dents with the bolts. This avoids the possibility of any dents joining up to make a groove which might result in EBB movement.

Whatever you do, avoid tightening the bolts into the thin part of the EBB. This will prevent any possibility of bolt damage to the bottom bracket bearing assembly.

Wise words.