Bottom bracket gunk

BugsBunny
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Bottom bracket gunk

Postby BugsBunny » Tue Jun 05, 2018 4:43 pm

Took my bike for a major service and got this pic from the mechanic. Shocking amount of gunk and rust.
:shock:

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10speedsemiracer
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Location: Melbourne, Eastern Suburbs, near the hills,

Re: Bottom bracket gunk

Postby 10speedsemiracer » Tue Jun 05, 2018 4:58 pm

Bleah !
Mmm, SunTour

HenryCharlie
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Re: Bottom bracket gunk

Postby HenryCharlie » Thu Jun 07, 2018 1:26 pm

How many K's has the bottom bracket done?
I overtook some people going uphill once.

BugsBunny
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Re: Bottom bracket gunk

Postby BugsBunny » Thu Jun 07, 2018 5:21 pm

I would say 2000km - since Sept 2017 thereabouts. I went on a 5 day tour in Japan early this year and it was torrential rain (all 5 days). It was a newbie mistake not to come back and have it all cleaned. I seldom ride in rain - so I think the silt and rain from the Japan ride is the major cause.

macca33
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Re: Bottom bracket gunk

Postby macca33 » Thu Jun 07, 2018 7:21 pm

Or, there wasn't a whole lot of grease in there when they did the service.....
CAAD10 Berzerker & Focus Mares CX & Ridley Noah-R Team

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Tim
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Re: Bottom bracket gunk

Postby Tim » Thu Jun 07, 2018 8:06 pm

Do you wash the bike with a hose or Gerni type cleaner? Water and detergents or degreasers?
I reckon that is mostly rust rather than dirt embedded in emulsified (water spoiled) bearing grease.
A fine example of very poorly sealed press-fit "sealed" cartridge bearings.
I get more than ten times that mileage from bottom brackets. I don't clean my bikes with water, particularly a hose and no detergents or degreasers. Occasional wet weather, many more than 5 days.
The older style square taper type, properly sealed BB's are known to last well over 50,000km's.
Bike's are chit these days. Not designed to last. But they do go fast and I do like them. Old and new.

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10speedsemiracer
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Re: Bottom bracket gunk

Postby 10speedsemiracer » Thu Jun 07, 2018 8:18 pm

Tim wrote:......
Bike's are chit these days. Not designed to last. But they do go fast and I do like them. Old and new.


I'm with Tim on this, in that I regard modern bikes as appliances as opposed to older bikes being a more classical, diverse expression of design and function.
I like some features of modern bikes (aside from anything involving press-fit) and appreciate modern drivelines especially, but a 70s or 80s high-end bike will always do more for me than the current generic stuff.
Mmm, SunTour

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Duck!
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Re: Bottom bracket gunk

Postby Duck! » Thu Jun 07, 2018 8:50 pm

Tim wrote:Do you wash the bike with a hose or Gerni type cleaner? Water and detergents or degreasers?
I reckon that is mostly rust rather than dirt embedded in emulsified (water spoiled) bearing grease.
A fine example of very poorly sealed press-fit "sealed" cartridge bearings.
I get more than ten times that mileage from bottom brackets. I don't clean my bikes with water, particularly a hose and no detergents or degreasers. Occasional wet weather, many more than 5 days.
The older style square taper type, properly sealed BB's are known to last well over 50,000km's.
Bike's are chit these days. Not designed to last. But they do go fast and I do like them. Old and new.

The real culprit here is the direct contact between the aluminium crank spindle and the steel bearing shells. Other elements accelerate it, but the underlying issue is the fundamentally reactive relationship between the two different metals. Short version: bad design.
I had a thought, but it got run over as it crossed my mind.

BugsBunny
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Re: Bottom bracket gunk

Postby BugsBunny » Fri Jun 08, 2018 1:57 pm

Thanks guys. This was a costly learning experience.

After a full strip and rebuild, I needed a new BB and three of the 4 rear bearings needed replacing. And these are all less than a year old.

Bugs

stevebni
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Re: Bottom bracket gunk

Postby stevebni » Thu Jun 14, 2018 9:59 am

Amongst other things, I've been a bike mechanic for over thirty years, that's really not a lot of gunk. I'd say it's pretty clean really, given how much gunk most modern bikes let in. Most get's in via the seat tube.

If you want to see some real gunk, check out my workshops Insta feed: https://www.instagram.com/bikespannerni/

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10speedsemiracer
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Re: Bottom bracket gunk

Postby 10speedsemiracer » Thu Jun 14, 2018 10:06 am

stevebni wrote:Amongst other things, I've been a bike mechanic for over thirty years, that's really not a lot of gunk. I'd say it's pretty clean really, given how much gunk most modern bikes let in. Most get's in via the seat tube.

If you want to see some real gunk, check out my workshops Insta feed: https://www.instagram.com/bikespannerni/


Just had a scroll, am now traumatized. The Vinnie meme summed it up well.

It's been emotional
Mmm, SunTour

stevebni
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Re: Bottom bracket gunk

Postby stevebni » Thu Jun 14, 2018 11:40 am

LOL.

You do need to bear in mind we're in Ireland (I'm in Aus at the mo, but I live in, and the workshop is in, Ireland). Bit wetter there than here!

Seized BB's with collapsed bearings is a pretty common occurrence. We have a range of hammers to deal with them ;-)

The Vinnie meme was from the time I closed my bike shop to transition to a workshop only business.

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