Bottom bracket replacement

[Riverboots]

Hi all.
The original external bearings on my 906 (3000km) came loose whilst cycling and upon inspection were found to be badly worn, dirt and wet having got in.

I noticed that the frame still has a lot of paint where i've read it should have been "chased and faced" before installing the original BB.
1. How critical is this for a bike with external BB's?
2. Could this have caused the premature failure of my bearings?
3. Is it worth scraping the paint away myself or is it strictly a proff job?
4. Can anyone at Wisper shed light on if the bike should normally be delivered "chased and faced" during quality control?
Regards
James

 

[trex]

"chased and faced" on a Chinese bike? it's more like 'dip and shine', they are not going to face the shell before fitting the BB from fear of cracking the spray paint.
3000km sounds a little low but you could fit a new Shimano BB with cartridge bearings from ebay for £10.

 

[Deleted member 4366]

Did it go on the pedal sensor side? If so, I think it's because the magnet disc interferes with the lip on the bearing seal. I always chamfer the inner corner of the magnet disc to make sure that it stays well clear of the seal's lip.

 

[Riverboots]

Thankyou for the replies.
Trex: You don't think I would gain anything by removing the paint myself then? (see pics below).

I did try to fit a shimano SM-BB70 but the chap in the shop eventually took it back after I showed him that the crank does not go all the way through this type as the original did. I assume the extra clearance is necessary for the sensor on this bike. In the end I sourced an original Samox BB from the Wisper dealer in Oslo to be safe.

d8veh: It did indeed become loose on the sensor side. I first noticed when my pedals started to seize while cycling and the only remedy was to pedal backwards! Both bearings are horribly worn and "grumbling".
These are the parts I have after removal (minus the crank and pedals!) Which is the magnetic disk you refer to? Is it the small ring 2nd left? I hope I'm not missing anything!

Regards
James

 

[Deleted member 4366]

The magnet disc is the black plastic disc with magnets in. it's not in any of your photos. IIRC it's more like a star than a disc and it has little flutes on the inner diameter, which are the things that need to e chamfered back. It's probably sitting behind the chain-wheel on the main shaft.

 

[Riverboots]

Phew! Found hiding under the work stand for my bike.


Many thanks for the help

 

[Deleted member 4366]

This one should do the job nicely:

http://www.ebay.co.uk/itm/Shimano-SM-BB51-Hollowtech-ll-MTB-Bottom-Bracket-/400641314096?pt=UK_sportsleisure_cycling_bikeparts_SR&hash=item5d48154d30

 

[stevel]

Thankyou for the replies.
Trex: You don't think I would gain anything by removing the paint myself then? (see pics below).

I did try to fit a shimano SM-BB70 but the chap in the shop eventually took it back after I showed him that the crank does not go all the way through this type as the original did. I assume the extra clearance is necessary for the sensor on this bike. In the end I sourced an original Samox BB from the Wisper dealer in Oslo to be safe.

d8veh: It did indeed become loose on the sensor side. I first noticed when my pedals started to seize while cycling and the only remedy was to pedal backwards! Both bearings are horribly worn and "grumbling".
These are the parts I have after removal (minus the crank and pedals!) Which is the magnetic disk you refer to? Is it the small ring 2nd left? I hope I'm not missing anything!

Regards
James



View attachment 7821
View attachment 7818 View attachment 7819

Interesting as my 906 Alpino is fitted with a sealed cartridge bottom bracket
http://www.ebay.co.uk/itm/All-Sizes-Raleigh-Shimano-Type-Bike-Bicycle-BB-Bottom-Bracket-Sealed-Cartridge/110979389130?_trksid=p2045573.c100033.m2042&_trkparms=aid=111000&algo=REC.RVI&ao=1&asc=20205&meid=4720263447329164915&pid=100033&prg=9064&rk=0&rkt=4&sd=181006959309

 

[Clockwise]

http://www.chainreactioncycles.com/bottom-brackets?sort=pricelow

Enjoy.

 

[Wisper Bikes]

Thanks Everyone, especially Dave for their assistance on this one.

I hope all is well now Riverbooots?

Best regards

David