Dura Ace Crankset - teeth worn?

Dura Ace Crankset - teeth worn?

Postby merlin6014 » Wed Mar 13, 2013 4:32 pm

Guys just bought this Dura Ace 7900 crankset (53/39) second hand from ebay. Seller claimed excellent condition, "ridden less than 500km".

Now on the 53 ring the teeth seem to be differing lengths...is this normal or suggestive of a lot of wear?

Can anyone with a Dura Ace crank check theirs against my photos please.

Here is some photos:

Image

Image

Image
Image
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by BNA » Wed Mar 13, 2013 5:09 pm

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Re: Dura Ace Crankset - teeth worn?

Postby toolonglegs » Wed Mar 13, 2013 5:09 pm

Plenty of life left in them yet... they haven't done much work at all. I just threw a set away... they looked a bit different to that :lol: .
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Re: Dura Ace Crankset - teeth worn?

Postby open roader » Wed Mar 13, 2013 5:29 pm

toolonglegs wrote:Plenty of life left in them yet...


+1

The teeth will resemble a shark fin where they are worn down - ie have a distinct slant on the drive side of the tooth where the chain is towed over the top of the ring.
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Re: Dura Ace Crankset - teeth worn?

Postby darkhorse75 » Wed Mar 13, 2013 5:44 pm

The difference in teeth height is to aid shifting AFAIK.
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Re: Dura Ace Crankset - teeth worn?

Postby R12RT » Wed Mar 13, 2013 5:48 pm

I just replaced my Ultegra 53t chainring and the teeth looked a lot less worn than these.

I changed the chain ring because I was having problems shifting and sometimes the chain would drop onto the small ring when I changed gears on the rear. Also, I was finding it impossible to tune the rear derailleur.

Now with a new chainring all is good.
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Re: Dura Ace Crankset - teeth worn?

Postby merlin6014 » Wed Mar 13, 2013 5:53 pm

OK thats a relief. Picked em up for $150 by the way. Sounds like I got a decent deal.
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Re: Dura Ace Crankset - teeth worn?

Postby AlMac » Wed Mar 13, 2013 7:01 pm

Shimano teeth aren't uniform in length to aid shifting.

Bit hard to tell from your photo.

Ride it and see.
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Re: Dura Ace Crankset - teeth worn?

Postby Howzat » Wed Mar 13, 2013 7:23 pm

merlin6014 wrote:Picked em up for $150 by the way.

:shock: :shock: ... Mate, these are fit to be binned - you got totally ripped off. But not to worry, I have an old fixie I'm doing up and I'll take 'em off your hands for say $100. :D :D
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Re: Dura Ace Crankset - teeth worn?

Postby open roader » Wed Mar 13, 2013 8:11 pm

From a practical viewpoint the chainrings are not shagged until you get chain drop/pickup/jumping issues. Fit them up, re-tune the derailer and give them a hammering, you'll find out soon enough.

From the images supplied the small ring looks like it's done very little work at all. The teeth will have slightly different shapes and profiles by design with ramps and pins etc assisting to pick up and drop the chain off and onto the rings.
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Re: Dura Ace Crankset - teeth worn?

Postby kukamunga » Wed Mar 13, 2013 8:25 pm

Get yourself a chain checker and check your chain wear after every few hundred k's. Replace your chain regularly enough (~$60), and you won't be having to replace $300 - $400 worth of DuraAce chainrings for quite a while
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