It this Campa 39t chain ring worn out?

Discuss light weight issues concerning road bikes & parts.
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Permon
Posts: 640
Joined: Mon Jun 23, 2008 8:52 am

by Permon

Hello guys, please Your opinions.

I think that my Campa chainring 39t is worn out. How I came to this conclusion?
Well start with the facts:
- the crankset has run about 30 000 km so far
- I change chains even earlier than Campagnolo recomends (they recommend 132,6mm....I usually change at 132,5mm)
- I have been running new cassete at this moment (3000km)

I changed chain and when I jumped on the bike I can hear very loud sound coming from small chainring under load (on all sprockect 11-25). The big chainring is silent.
It sounds like the teeth are eating the chain. It sound like that only under load..... silent while spinning easily.

As mentioned:
- NEW chain
- almost NEW cassete
- big chainring silent (it has more teeth and I do not put so much load on the flats = less worn out)
So it brings me to the conclusion of worn our small chain ring.

Am I right?
Any other ideas?

Take a look at the pictures.
Attachments
1.jpg

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bikerjulio
Posts: 1901
Joined: Fri Dec 11, 2009 10:38 pm
Location: Welland, Ontario

by bikerjulio

There is some wear for sure on the backside of the teeth, but I'd never have said that it looks "worn out".

I'd try a few rides and see if the chain loosens up a little.
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

Permon
Posts: 640
Joined: Mon Jun 23, 2008 8:52 am

by Permon

Yeah, I agree about the apearence of the ring......by my opinion 30 000 km for a chainring is not much and the ring looks OK to me.
I have been running Campa staff from 1994 and I never had to change rings (usually made like 40 000km on each groupset)
The type of noise I am experiencing now is totally new to me.... I usually experience totally silent drivetrain after new chain is put on. Different story now :unbelievable:

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tommasini
Posts: 1297
Joined: Sun Nov 02, 2003 6:48 am
Location: Central USA
Contact:

by tommasini

There is a small amount of material worn aware from the middle vertical of the teeth. That's right where the roller rests against the teeth. That can change the dimensional characteristics of the teeth. But overall it looks pretty good.

In the work stand try a test - see if you can put a bit of pressure on the crankarm and then watch the chain from about the 12 oclock to about 3 p.m position on the chainring. Does it look like the chain is attempting to rise up a little bit out of the bottom seat of the teeth? That would account for a nasty noise as the chain is trying to find an equilibrium so to speak with the teeth............if so then the teeth that are no longer optimal.

BTW - I use the combination of 132.6mm (catches roller wear the best) and 1/32" per foot (catches pivot wear the best). Sometimes I have a chain approaching the 132.6 and looking great on length elongation (the 1/32"). But sometimes it's the other way. So together I don't let a chain get out of hand. In my opinion, roller wear (if consistent) won't greatly affect the 1/2" on center of one link to the next. But pin wear will cause the chain overall to get longer - thus giving the affect of the chain no longer being 1/2" on center and greatly messing with chainrings and cogs.

campagnolo321
Posts: 30
Joined: Sat Dec 21, 2013 7:17 pm

by campagnolo321

Permon, the symptoms you describe suggest it it worn beyond being heathy to use with a good or new condition chain, even the picture sugestes its worn to the point of needing to be replaced.

For the members suggesting its not worn I suggest you go to Specsaves and have another look at the photo !

Change the ring my friend.

Permon
Posts: 640
Joined: Mon Jun 23, 2008 8:52 am

by Permon

Thanx for opinion.
I do agree with the other posters that it looks quite OK......looking very much like new rings.
Considering it has 30 000km and I am changing chains often, it seems to me surprising that chainring is worn out already.

The fact is, that everything speaks for the worn out chainring....(new chain, almost new cassete, silent drivetrain when running big ring, small ring silent when spinning easily....)

What do you mean by:
"I suggest you go to Specsaves and have another look at the photo !"

What is Specsave?

campagnolo321
Posts: 30
Joined: Sat Dec 21, 2013 7:17 pm

by campagnolo321

What is Specsave?[/quote]

Sorry, this is my sense of humour as Specsavers is an opticians here in the UK !

But for piece of mind change the ring, inner Campag rings dont cost the earth and at least once a new one is fitted shifting should improve, will be smoother running and quieter too !


Glad you are a Campag man :D

em3
Posts: 888
Joined: Tue Dec 23, 2008 2:57 pm
Location: NYC

by em3

Permon, I recently had the exact same experience, with 39T on Super Record 2009 with about 40K kilometers. After installing new chain I sensed a bit of rubbing and noise, sort of like when your chain is too close to cogs. After close inspection I noticed that chain was actually snagging a bit to the small chainring, especially under load. I inspected the chainring and used a bit or emory to eliminate small snags or burrs, but the issue persisted. The chainring did not look especially worn, but I went ahead and changed the ring and the issue was solved. EM3
______________

Permon
Posts: 640
Joined: Mon Jun 23, 2008 8:52 am

by Permon

em3 wrote:I sensed a bit of rubbing and noise, sort of like when your chain is too close to cogs.


Yes, this is exactly what I can hear.....it sounds like the RD is right bellow cogs and pulleys are meeting cogs, but it is not the case.
So, I am ordering new chainring.

Thank You guys! I appreaciate Your help. :thumbup:

Permon
Posts: 640
Joined: Mon Jun 23, 2008 8:52 am

by Permon

One more question, sorry :lol:

How do I unscrew this bolt?
There is something in the torx head, so my torx does not fit :unbelievable:

Thanx
Attachments
2.jpg

em3
Posts: 888
Joined: Tue Dec 23, 2008 2:57 pm
Location: NYC

by em3

...just take a small needle nose and pull out the plastic retainer (slides right out).

Also, when re-assembling take care not to over tighten your chainring bolts.. Campagnolo recommends 8 Nm.

EM3
______________

Permon
Posts: 640
Joined: Mon Jun 23, 2008 8:52 am

by Permon

Thanx :thumbup:

Permon
Posts: 640
Joined: Mon Jun 23, 2008 8:52 am

by Permon

Chainring changed. Problem solved. :thumbup:
The old one was really worn out. :noidea:

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bikerjulio
Posts: 1901
Joined: Fri Dec 11, 2009 10:38 pm
Location: Welland, Ontario

by bikerjulio

Well, I've see a lot worse than that, but looks like I was wrong again.

Glad problem fixed.
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

Permon
Posts: 640
Joined: Mon Jun 23, 2008 8:52 am

by Permon

Yeah, it is always hard to judge by a photo.
Anyway, it is great to have an option to discuss issues like this on the forum. :up:

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