What is the goo that builds up on chains & cassettes?

[αdαmsκι]

I've just been removing all the black goo that collects on the chain, cassette etc. over time & I was wondering what the black goo actually is and where does it come from? I realise it's partly water and grit spraying up from the road as you don't need to degrease stuff as much in the summer months, but how can water and grit turn into such horrible, black, greasy goo?

NB: If you are unsure what I'm talking about then you clearly clean you're bike far too often. I suggest riding it for a good few months without cleaning the bike at all and you should then have a good build-up of the goo to which I refer.

[Greenbank]

but how can water and grit turn into such horrible, black, greasy goo?

dirt, grit, oil/lube a.k.a. grinding paste.

[geraldc]

It's metal particles from chain and cog wear that turn oil black.

Apparently if you take your chain cleaning fluid and leave it in a jar, the metal particles will sink to the bottom, and you can use the cleaning fluid again. Unfortunately, I'm not that organised.

[Greenbank]

Apparently if you take your chain cleaning fluid and leave it in a jar, the metal particles will sink to the bottom, and you can use the cleaning fluid again. Unfortunately, I'm not that organised.

I use a solvent (white spirit) that means that enough stuff is dissolved into the solution for it to be permanently discoloured. My chain cleaning jar has been sitting in the shed undisturbed for 4 months and is the same black liquid as it was when I last used it, and the time before that (another 4 months previous). Mind you, it still works a treat, despite looking filthy itself.

[Chris S]

I use diesel. Then use the diesel to light the woodburner  .

Waste not, want not...

[numbnuts]

I call it s-h-i-t 

[clarion]

It's faerie phlegm.

[Mr Larrington]

'tis skog^tm

[hellymedic]

Skog™ is Mr Larrington's excellent term for this.

Oil + Grease + metal worn off sprocket, chain & chainwheel + brake rubber + wheel rim dust + road muck + water + anything else you can name...

[Pingu]

Skog™ is Mr Larrington's excellent term for this.

Oil + Grease + metal worn off sprocket, chain & chainwheel + brake rubber + wheel rim dust + road muck + water + anything else you can name...

Grub wee

[Zoidburg]

Dark Matter.

[Biggsy]

The gunk on chains is mostly thickened oil/grease + metal particles. 

Also there is diesel soot from lorries, vans, buses and taxis if you ride on busy roads.  I get a fine black powder on my bike frames, and presumably in my lungs too.

[hellymedic]

Grub wee

We could do without policemen urinating on the forum, thank you very much.

Even if it's a Monsta Thorn? 

[Greenbank]

I get a fine black powder on my bike frames, and presumably in my lungs too.

That's nothing to worry about, several studies have shown that this is no different to the amount that ends up in your lungs if you'd driven along the same route in a motor vehicle (for journeys of an equal duration in traffic).

[rogerzilla]

Having washed a chain in solvent, filtered the crud and tried a magnet on it, it's road dirt mixed with oil.  There's no discernible metal in there.  Logically there must be *some* due to chain and sprocket wear, but it's a very small part of the mix.

[Quisling]

Chain smeg

[mrcharly-YHT]

The gunk on chains is mostly thickened oil/grease + metal particles. 

In my case it is mud, cow poo and metal particles mixed with oil.

This morning the mud from the road built up until my front wheel wouldn't turn.  

[delthebike]

Chain smeg

Chain dirt/smeg. 
It is not skog, Mr. Larrington, skog comes off the surface you are riding on.

[Biggsy]

That's nothing to worry about, several studies have shown that this is no different to the amount that ends up in your lungs if you'd driven along the same route in a motor vehicle (for journeys of an equal duration in traffic).

The fact that cycling is no more dangerous in that way than driving doesn't stop me worrying about what is happening to my lungs.  Motorists should be worried too!  Most worryingly, I've heard that the particles are neither small enough nor large enough to ever get out - unlike tobaco smoke particles!

[Greenbank]

The fact that cycling is no more dangerous in that way than driving doesn't stop me worrying about what is happening to my lungs.

I have to get to work one way or another, and there's no avoiding traffic given my office location.

I suppose the air quality could be better if I took the train in every day, but I'd be missing out on an hour of good cardiovascular workout which I'd hope outweighs the possible negative aspects of crap in the lungs.

The face masks are known to be a bit of a sham. For them to have any real useful effect in filtering out nasty stuff they'd be far too restrictive to use, you'd simply wouldn't be able to get enough air through them to support exercise like cycling.

[Biggsy]

A chain of strong ball magnets (all of the same size) after dipping in a jar of bike chain goo in white spirit.



Clearly a high steel content in the goo for it to be attracted like that, and I won't be able to get it all off.

[clarion]

Hummers will be along in a moment to comment on how that picture reminds him of a sex toy, but I'm too innocent to know anything about that sort of thing. 

Do carry on...

[Greenbank]

Clearly a high steel content in the goo for it to be attracted like that, and I won't be able to get it all off.

Find someone with a bigger stronger magnet and pass the problem on to them...

[Biggsy]

Hummers will be along in a moment to comment on how that picture reminds him of a sex toy, but I'm too innocent to know anything about that sort of thing. 

Surely no one can be that filthy?  Don't answer that - at least not in The Knowledge

[Adrian]

You have never met Hummers?