Excesssive wear on chain ring !!!

[intern]

 

cut cut cut

 

 

 If in doubt' date=' head to the LBSand have them measure the chain with that wear gadget goodie they have. Just make sure they're not the skanky ones who will say replace the lot regardless of the condition....

[/quote']

 

 

No bru, that's *** advice. Chain wear gadget goodies are inconsistent and most bike shops don't have a clue how to measure chain wear. Not so schweeet advice.

 

 

Oh my, so sorry, contact Professor Bornman then and have a look at his dissertations on chain wear. Wait, wait - check this Just make sure they're not the skanky ones who will say replace the lot regardless of the condition....

Hard to believe, but there are in fact some bike shops and some wrenchers who know how bike components work....

 

[intern]

Guess what I used on my chain in the Cape Epic? Squirt. Awesome stuff, and what I really liked about it was that you could wash the chain and cassette and chainrings with hot water and sunlight after each stage, and all the dust gunk and goo just scrubbed right off. (OK I must admit that it wasn't me that was washing my bike it was my girlfriend...beat that).

 

Derailleur moving parts got a touch of Motorex to keep it 'schweet' (like my 'not so' advice which I was dispensing will-nilly and sans license.)

 

Sure you have to reapply more frequently than other looobs, but I for one will stick to Squirt. Or will Squirt stick to me? And my garage floor? (As an aside, looobing a garage floor..hahahah)

 

OH! And I still have the same chain on my bike...and I race that bad boy as often as I can and ride it probably twice a week.

 

Now where's my millions of denarii for endorsing that crap?

[Spinners]

Johann you still havent answered my question on your experience. Please stop trying to change the subject and make me look like a coward, and just tell us all your experience....

[intern]

 

Spinners, that is an old form of avoiding the issue called ad hominem or sometimes 'poisoning the well', i.e. playing the man and not the ball. Learned that in philosophy class, of all bucking fizarre places to find oneself.

 

Check it here.

 

http://en.wikipedia.org/wiki/Ad_hominem

 

Who would of thought a simple request about chainrings...haha.

 

Anyway, I would have thought that sharing one's experiences on what does and don't work would be a good idea. Some folks like putting engine oil on their garage floors, others like putting Squirt on their chains. What works for me might not work for you, and who am I to say YOU'RE WRONG! I'll leave that to the 'experts'. Pinch of salt not included.

 

 

intern2008-09-30 12:03:14

[bruce]

Johann you still havent answered my question on your experience. Please stop trying to change the subject and make me look like a coward' date=' and just tell us all your experience....[/quote']

 

Graduate Mechanical Engineer IIRC.

[Willehond]

...but back to the ORIGINAL topic (just for the record: I love Squirt because it is clean and my chain doesn't squeek as quickly as with Whit Lightning and my chains last - good enough for me!) - like I said back to the original question:

 

How the heck do you kill a chainring?  Yes, the cluster gets mothered when your chain goes out of spec, but I have never damaged the chainring!  Isn't there something else wrong here?

[intern]

 

Johann you still havent answered my question on your experience. Please stop trying to change the subject and make me look like a coward' date=' and just tell us all your experience....[/quote']

 

Graduate Mechanical Engineer IIRC.

 

Not sure that they teach bike repairs for engineering students? That's called an appeal to authority fallacy, like believing a medical doctor's theories that the Large Hadron Collider is going to fry the universe just cause he's a doc and should know.

 

http://en.wikipedia.org/wiki/Appeal_to_authority

 

Man, I really was paying attention in philosophy class. Pity I only got 52% for it.

 

[intern]

getting this feeling I'm gonna be on the receiving end of fatty's pink ink I think. Uh oh. 

[Johan Bornman]

[quote name=Willehond

Cut cut cut

 

How the heck do you kill a chainring?  Yes' date=' the cluster gets mothered when your chain goes out of spec, but I have never damaged the chainring!  Isn't there something else wrong here?

[/quote]

 

Your observations is correct. The difference between a chainring and a rear sprocket (both are technically sprockets, before I get fingered) is that the chainring is a driving sprocket and the rear sprocket is a driven sprocket.

 

The practical difference is that a chain enters the driven sprocket sans tension and the driving sprocket under tension.

 

Therefore, if the chain is elongated beyond spec, it will float on top of the driven sprocket's cogs (teeth) on entry and never recover from that position. If the same chain enters the driving sprocket, it does so under tremendous force and any discrepancies between chain length and cog pitch is "forced out" and the chain and sprocket will mesh perfectly.

 

A driving sprocket eventually fails by causing chain suck on the smaller of the chainrings and worn cogs on the larger chainring that eventually have to grip on the chain whatsoever.

 

On road bikes the driving sprocket is so big that it almost never causes chain suck and people can keep on riding them untill they eventually completely fail to hold the chain. On mountain bikes we usually have to replace them because they start to suck.

 

That's why you get the impression that you almost never damage a chainring (aka front sprocket).

 

An elongated chain damages a rear sprocket but not a front one. A damaged rear sprocket will not damage a chain.

 

The most sensible way of handling chain replacement is to keep replacing the chain when it reaches 1% elongation and only to replace the rear cassette if the new chain causes it to slip. That way you get maximum life out of all components.

 

 

 

 

 

Johan Bornman2008-09-30 12:57:44

[Willehond]

Johann you still havent answered my question on your experience. Please stop trying to change the subject and make me look like a coward' date=' and just tell us all your experience....[/quote']

 

Graduate Mechanical Engineer IIRC.

Not sure that they teach bike repairs for engineering students? That's called an appeal to authority fallacy, like believing a medical doctor's theories that the Large Hadron Collider is going to fry the universe just cause he's a doc and should know.

http://en.wikipedia.org/wiki/Appeal_to_authority

Man, I really was paying attention in philosophy class. Pity I only got 52% for it.

 OK, now I kind of miss you argument.  Sounds like you just want to have a fight for the sake of it?  Weak argument if that is the case

 

Any specific points about his statements you want to attack?

[intern]

Nobody's fighting, Willehond. Just making the point that anyone can be a smartypants if they want to be.

 

[Minion]

 

 

believing a medical doctor's theories that the Large Hadron Collider is going to fry the universe just cause he's a doc and should know.

Probably more like believing a cardiologists theories on the functioning of a horse's heart.

 

I would say that around 90% (in my experience) of what is taught to mechanical engineers has no direct link to what they eventually do in the work place. The theoretical knowledge obtained can, however, be readily adapted to most situations.

 

It isn't necessary to specifically teach bike repair in order to understand the stresses and mechanical phenomena that affect a bicycle. I would go so far to say that any mechanical engineer who cannot gain a reasonable understanding of bike functioning within a couple of weeks of study is unworthy of the title.

Edman2008-09-30 13:01:12

[Willehond]

Cut cut cut

 

 On mountain bikes we usually have to replace them because they start to suck.

 

................

  

Johan, chainsuck can have many causes, so how do you test to determine that the chainring is at fault?

[intern]

And ja, nobody likes a smartypants, I'm well aware of that.

[Willehond]

Nobody's fighting' date=' Willehond. Just making the point that anyone can be a smartypants if they want to be.
[/quote']

 

You seem to be exceptionally proficient in that regard!

[Johan Bornman]

Cut cut cut

 

 On mountain bikes we usually have to replace them because they start to suck.

 

................

  

Johan' date=' chainsuck can have many causes, so how do you test to determine that the chainring is at fault?

[/quote']

 

I should have added the other cause as well - dirt. A chain sucks i.e. does not release from the sprockets at its designed exit point when something holds it onto the sprocket. This something could be worn and hooked cogs (teeth) as in the scenario I desribed above or dirt. A bent cog is obvious too.

 

How do you determine if the chainring is past its prime? If it sucks even when nice and clean and lubricated with oil. Sometimes the hooked teeth are very visible and sometimes not. I find that the more expensive the chainring, the less wear it can tolerate before sucking. Murphy concurs with this.

 

Certain shifting habits can bring on suck but will not be the cause of the suck, just the catalyst for something thats waiting to happen.