Fitting a new BB into the Eccentric (Raven Sport Tour)

[jr970]

I'm helping a friend replace the Eccentric on his Raven Sport Tour. We had an issue on a tour recently where it became apparent that the LBS who "serviced" the bike before the tour had omitted to sufficiently tighten the securing bolts on the Eccentric after fitting a new chain and the whole unit started to slip sideways  .

We had to do a bit of temporary fix en-route but did'nt have the right eccentric tool & suspect the eccentric might have been damaged either in the field-fix or by the LBS tightening up on the thin section....

Decided we might as well fit a new eccentric & BB together as it's quite a high mileage bike.

My question is on the best way to fit & torque a new square taper BB into a new eccentric. It it best fit off the bike using a vice & some padding?

I'm thinking of using the Tange Seiki BB
https://www.sjscycles.co.uk/bottom-brackets/tange-seiki-ln3922-73-mm-jis-english-square-taper-bottom-bracket-107-mm/

Any experience of these ?

[geocycle]

I put a new BB in mine while on the bike.  But I don’t see any problem in doing it in a padded or wood lined vice or workmate.  If it’s in the frame it should hold firm enough on the EBB bolts to get to a reasonable torque. Obviously use lots of your favourite grease.  I don’t know the specific BB you mentioned.

[Danneaux]

As a data point, I too had no problem removing my old bottom bracket and fitting a new (in my case, external) BB in my Thorn Nomad with the eccentric secured in the frame.

As Geo' cautioned, be sure to use this as an opportunity to apply fresh grease to your eccentric so you can avoid future problems with galvanic corrosion and so the eccentric can be easily adjusted to take up chain slack at some future point.

Best, Dan.

[UKTony]

+1
also on Mk2 Nomad with what I think is a similar EBB and square taper BB (in my case Shimano UN55 110x73) setup. I always torque the two pointy EBB securing screws to about 13Nm (the recommended range is 10 to 17Nm) and the eccentric didn’t rotate when tightening the BB.

[mickeg]

One more here that had no trouble using the eccentric in the bike when I installed the bottom bracket.

If you have the same eccentric as in my Nomad Mk II, I used a couple rubber bands on the eccentric bolts to make sure that they do not loosen over time.  See photo.  Rubber bands are black, were cut from an inner tube.

And I assume you already know that if your eccentric is the same as on my Nomad Mk II, you put the thick part of the eccentric on the bottom, you do not want those pinch bolts to press on the thin part of the eccentric or you could deform the eccentric.

[jr970]

Thanks for all the advice... just what I wanted to know

[PH]

I'm thinking of using the Tange Seiki BB
https://www.sjscycles.co.uk/bottom-brackets/tange-seiki-ln3922-73-mm-jis-english-square-taper-bottom-bracket-107-mm/

Any experience of these ?

What others have said about changing BB in frame.
I have an IRD BB which uses the same bearings as that one, Tange Seiki has an excellent reputation and I have no reason to doubt it.  Sorry if it's obvious, but do check sizes, the original Raven and Sports were 68mm shells.