Author Topic: Replacing EBB and bottom bracket together.  (Read 487 times)

rafiki

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Replacing EBB and bottom bracket together.
« on: September 11, 2018, 10:38:20 AM »
I'm about to replace the EBB and BB together on my Sterling. The EBB is secured with the two pointy bolts through the BB shell. As I am replacing everything should I build the new system loosely outside the shell and slide it in or should I insert the EBB and then install the BB?

Danneaux

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Re: Replacing EBB and bottom bracket together.
« Reply #1 on: September 11, 2018, 03:23:06 PM »
Hi Brian,

Because the external BB cups can extend beyond the eccentric, they can make the lot too large to insert in the frame if pre-assembled. For this reason I assemble the cups into the eccentric in the frame, making sure to first coat the inside of the frame's steel hanger with grease or anti-seize to prevent future galling against the aluminum eccentric.

In the case of a new external BB and eccentric, to prevent putting unneeded dents in the eccentric I'd first put the eccentric into the greased frame, then hand-tighten the cups, spacers, and sleeve into the eccentric and then slide the crank and spindle in from the right (no left crank arm installation needed at this point),mount the chain and turn the eccentric to set proper chain tension, then set and secure the grub screws so the eccentric is held firmly in place at the point where chain tension is proper.

I'd then slide the right arm and spindle out, properly torque the hand-tightened cups into the pre-secured eccentric insert, and then reassemble the crank and properly torque the left arm in place, keeping in mind the need for the left arm key, bearing preload and proper torque of the bolts.

The advantage of this is you only have one set of initial dents made by the grub screws in your new eccentric. For final cup torque, the eccentric already will be secured properly in the frame so you can secure the cups as intended. The chain can then be installed knowing the tension will be proper. The new eccentric will only have one set of dents in it, leaving the rest pristine for future adjustments.

Hope this helps.

Best,

Dan.

mickeg

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Re: Replacing EBB and bottom bracket together.
« Reply #2 on: September 11, 2018, 06:01:39 PM »
And just a reminder to put the pointy screws into the thick part of the eccentric.  I am sure you knew that but when doing something new it is easy to forget the simple things.

rafiki

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Re: Replacing EBB and bottom bracket together.
« Reply #3 on: September 11, 2018, 06:16:10 PM »
Thank you both. Very helpful.

rafiki

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Re: Replacing EBB and bottom bracket together.
« Reply #4 on: September 15, 2018, 03:07:33 PM »
All done. Everything is msooth and quiet whilst spinning along. However I am getting some creaking when pushing harder up an incline. It's not very loud, I don't hear it on the gravel but it's irritating cycling along the tarmac. The bearings were tightened as hard as I could and all the chainring bolts are tight. What should I be looking for to stop the noise?

mickeg

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Re: Replacing EBB and bottom bracket together.
« Reply #5 on: September 15, 2018, 05:16:59 PM »
If it is a square taper crank, that could creak if not tight enough.

I use SPD type pedals and shoes with cleats.  I often get a creaking sound between my shoe and pedal, it is rubber sole rubbing on the metal.

I am not sure which eccentric you have, if you have one like on my Nomad, are both bolts tight?  Note that I put a rubber band on my bolts so that they can not come unthreaded from vibration.  Someone on this forum suggested I make rubber bands out of inner tube rubber to hold up better in the outdoors which I did after I took the photo.  If you are curious, one of my bolts came loose but fortunately I found that before it was lost so I added the rubber band.


rafiki

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Re: Replacing EBB and bottom bracket together.
« Reply #6 on: September 15, 2018, 05:43:38 PM »
Thanks. It is a similar eccentric to your Nomad. Good tip about the rubber band, I had often wondered about those bolts becoming loose. I am wondering if the bolts should be tighter but I don't have a way of torquing them accurately yet. They are just as tight as I dare for the moment. Could that be the source of the creak  if they aren't tight enough?

I have an external bearing SM BB51B https://www.sjscycles.co.uk/bottom-brackets/shimano-deore-outboard-bearing-bottom-bracket-english-thread-bb51b/ sitting in this insert https://www.sjscycles.co.uk/bottom-brackets/eccentric-bottom-bracket-insert-fits-raven-mk2-sport-tour-etc-732mm-for-external-bearing-bottom-bracket-gold/

I've checked pedals for tightness and the noise isn't coming from the shoes.

Dave B

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Re: Replacing EBB and bottom bracket together.
« Reply #7 on: September 15, 2018, 09:18:03 PM »
I had a similar irritating noise what I think originated from my bottom bracket area. Went on for weeks and drove me up the wall.  Did all the normal stuff to no avail .It stopped when I  smeared copper anti seizure cream on the seatpost , whilst i had the seatpost removed  i also sprayed GT85   down the inside of the frame. The noise stopped and has never returned! !

rafiki

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Re: Replacing EBB and bottom bracket together.
« Reply #8 on: September 15, 2018, 09:42:54 PM »
Thanks but my seatpost is jammed solid. I wish I could get it out. The noise is definitely from the BB.

rafiki

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Re: Replacing EBB and bottom bracket together.
« Reply #9 on: October 22, 2018, 03:56:22 PM »
I am well and truly stumped! I seem to be stuck with this irritating creak from the BB for ever. With each pedal stroke when pushing hard there is a creaking sound left then right. I have now completely replaced the Hollowtech system eccentric and the BB51 external threaded bearings with new this afternoon and followed Dan's installation method to the letter but I have the exact same creaking from down there on the new unit. I can't help feeling it is something to do with that 2.5mm spacer. It's plastic and, I guess, compressible. I'm not sure why it is needed. I know from previous experience that if I dismantle the crank now there will be some slack that can be taken up on that side after my ride. On the unit I just replaced I did it four times, each time a bit of slack after almost standing on the spanner the day before. I am at a loss. Will I do damage if I dismantle and remove the spacer?