Bottom bracket gunk

[BugsBunny]

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

[10speedsemiracer]

Bleah !

[HenryCharlie]

How many K's has the bottom bracket done?

[BugsBunny]

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]

Or, there wasn't a whole lot of grease in there when they did the service.....

[Tim]

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.

[10speedsemiracer]

......
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.

[Duck!]

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.

[BugsBunny]

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]

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/

[10speedsemiracer]

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

[stevebni]

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.