Bottom bracket, shimano 105 10sp crank

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Bottom bracket, shimano 105 10sp crank

Postby saron » Sun Feb 10, 2008 12:30 pm

Can anyone point me in the right direction on the process for disassembling the bottom bracket on a road bike with 105 shimano crankset. After a wet ride the bottom bracket is making a grinding noise under load. Can the bottom bracket be greased or is it sealed bearings. :oops:



Postby Hawkeye » Sun Feb 10, 2008 10:30 pm

Not sure - depends on how recent your crankset is.

Sealed bearings can be cleaned and re-greased. You just have to be careful about removing the shields. If they're the rubber-shielded type a fine-tipped hobby knife can be used to get in under it and lift it away depending on the bearing type.

Some bearings have fine wire circlips around the outside edge to keep the shield in place that need to be removed with care, so look for this first, otherwise you could bend the shield and it will no longer be able to do its job.

Buy a can of brake cleaner to get rid of the existing grease, and use HTB as a minimum to replace it. Others may have better recommendations for grease to repack your bearigns with once cleaned.

I'm a bit surprised that a wet ride would cause this problem, unless you copped it from the side on the crank. If by any chance you might have used a hose to wash your bike down after the ride, always be careful to avoid spraying end-on at the bearings, as you can very easily wash grit into them. This includes wheelsets and headsets, and suspension pivots on an MTB.

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Postby mikesbytes » Sun Feb 10, 2008 11:46 pm

Sounds on bikes have a habit of not coming from where you think. Everyone thought the sound from my bike was coming from the bottom bracket but it was actually coming from the rear wheel.
If the R-1 rule is broken, what happens to N+1?

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Postby Mulger bill » Mon Feb 11, 2008 12:24 am

We'll need more info Saron.
What type of BB? Taper, Octalink, Hollowtech?
Removal will take specific tools, might cost more than asking the LBS to have a go...

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Worked a treat

Postby saron » Wed Feb 13, 2008 4:12 pm

Bought the tool from LBS.
Took about 5 minutes to take apart.
There was a built of water and grit inside frame.
Cleaned all the grit etc and regreased and took for a ride seems to be alright. the only question is how tight do you tighten the left crank?


Postby Hawkeye » Wed Feb 13, 2008 8:28 pm

If you have a torque wrench you should be able to download the tech spec sheets from here which will tell you how many Newton-metres of torque to use.

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Re: Worked a treat

Postby HappyHumber » Thu Feb 14, 2008 1:40 am

saron wrote:There was a built of water and grit inside frame.
Cleaned all the grit etc and regreased and took for a ride seems to be alright. the only question is how tight do you tighten the left crank?

Even though I'm fairly new to serious DIY bike maintenance and mechanics - has there been something of the value lost in recent years about having a drainage hole cut/machined/drilled into the lower most point of a frames BB shell?

The couple of new Surly frames I have had personally in the last 3 years have neither come with such a drainage hole. I rode my brand new Steamroller for about 2 weeks before I tore it down for a project. I got caught out in ONE (1) shower riding home in that time - and I couldn't get over how much liquid came out of the shell when I unscrewed out the BB.

I've had the small modification of a 5-8mm hole drilled in the lowest BB shell point suggested to me from a local frame builder and I've since done it on both of my Surlies. I also have seen such holes or fancy pants cutout shapes in a lot of the better quality steel frames I've seen online. My kerbside find Cro-Mo 80s MBK came with one.

Do any/many of the mass production manufacturers make this small mod to their frames these days? Surely whether the frame is CroMo, Al, Carbon Fibre, Ti, Polystyrene, Unobtainium or whatever - such a small mod would save moisture gathering around steel BB bearings??
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