Author Topic: chain suck gouge question  (Read 5603 times)

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Offline PEDALTOTHESEA

chain suck gouge question
« on: May 04, 2009, 08:36:27 pm »
Have a beautiful well cared for Atlantis and have incurred the dreaded
chain suck .  Chain took a swipe at my chain stay - about 1/4" long by
3/16 wide.  Gouge thru the paint and perhap at the deeper edge (one of
the long sides) at most the depth compared to the thickness of a
postcard ( and edge I could feel with my fingernail)  I'm hopeful and
95% sure i could not have incurred any real structural damage except
to my ego.  There is a 5% of me that would feel better if someone
could tell me the thickness of the chain stay just rear of the welded
tube that joins the two chain stays.

I dabbed it with west system epoxy simply to protect it from rust.

i've also taken steps to prevent further suck - replacing the worn
granny gear (22 tooth) and the middle 34 tooth chain ring both Carmina
TA specialites - all aluminum.  Also plan on replacing the chain.
Is that normal.
I use the granny gear quite a bit but less and less these days.
Nevertheless - i've only gotten about 3500 miles on it.  Is that
normal for an aluminum chainring?

Offline driftlessregion

Re: chain suck gouge question
« Reply #1 on: May 04, 2009, 09:15:29 pm »
Sorry to hear of the gouge in the paint. Been there. I can't answer the question of the stay. You might want to contact Grant Peterson at Rivendell since he designed the bike (grant@rivbike.com). 3500 miles isn't much for a chainring (the chain yes.) . Hold it up against a new one and compare the wear. Is yours getting pointy instead of nice flat tops? I suggest a chain watcher such as the one by Third Eye. It's a big thumb that pushes the chain onto the small ring and doesn't let it past on the inside.  There are others. Pros are even using a specific one for big carbon frames on their bikes. Mine has saved many a chain suck.
Good luck.

Offline staehpj1

Re: chain suck gouge question
« Reply #2 on: May 05, 2009, 07:23:14 am »
I have always found chain rings and cogs to both last a very long time unless the chain was used longer than it should have been.  If 12 full links measure 12 - 1/16" (center of pin to center of pin) it is time to be thinking about a new chain.  If 12 full links measure 12 - 1/8" it is likely that chain rings and cogs are damaged.

Personally I have usually had chains last 10,000 miles or so and chain rings longer.  Don't go by mileage though, measure it regularly.
« Last Edit: May 05, 2009, 07:25:25 am by staehpj1 »