# Gouge in chainstay - Did I destroy the frame?



## Strife21 (Apr 23, 2013)

I was trying to get off my middle chainring not really know what I was doing and not being super careful and I dug the teeth into the chainstay. 

It went further then the paint and into the metal. Did I destroy the frame? It dug into the aluminum a bit it appears.


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## kjlued (Jun 23, 2011)

Wow, that looks bad. Maybe it is a case where the photos make it look worse than it is.
Personally, if you are worried about it, I would take it by the bike shop and have somebody look it over in person.


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## Strife21 (Apr 23, 2013)

double post


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## kjlued (Jun 23, 2011)

I would probably ride it and keep an eye on it but I am not comfortable saying that over pics posted on the internet. Worse case scenario the bike can be turned in to a gravel grinder.


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## Strife21 (Apr 23, 2013)

yea those pictures look horrible. I remeasured its closer to 0.25 - 0.35mm deep. Removed them and put up a better one I took in day light.


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## Strife21 (Apr 23, 2013)

it kind of went in at a angle and pushed some of the metal up into a little lip as you can see. Its really hard to get a good picture based on its location.

So I took it to my local LBS and he said I have nothing to worry about. Said it wasn't deep enough to do any damage and that the part of the chain stay is usually pretty thick and I didn't compromise the stability. He filed down the lip of metal it pushed up and it looks a bit better.

I am still kinda worried, do you guys recommend getting a new frame? Any suggestions that wouldnt breakt he bank. Its cannondale trail 6 26 that upgraded pretty much all the parts on.

New 9 speed slx derauillers, deore crankset and deore shifters, and 2013 rock shox recon silver solo air shock.

So sad just got the fork and I'm worried I broke the frame.


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## Xtyling (Apr 21, 2011)

If you ride hard (AM or DH) then perhaps a new frame might be advisable. But from what I see in your picture I doubt you will encounter any problems with XC riding.


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## Strife21 (Apr 23, 2013)

Xtyling said:


> If you ride hard (AM or DH) then perhaps a new frame might be advisable. But from what I see in your picture I doubt you will encounter any problems with XC riding.


Yea its a XC bike. I was thinking of getting a dual suspension bike if I end up riding AM. Trails around me are mostly XC oriented. If I have to replace this frame it pretty much ends the idea of purchasing an AM bike. Simply won't have the funds


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## Xtyling (Apr 21, 2011)

You will stretch and save money if you continue to use your current frame. Just be cautious to inspect the frame for any stress cracks or bends before and after your rides. That gash will probably start to corrode so some touch up paint may be needed.

I'm pretty sure you will be able to ride that frame for another 2-3 years and by that time you'd have enough savings for your AM frame.


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## kjlued (Jun 23, 2011)

Inspecting the frame before and after rides is something we all should do every time but most of us fail to do almost every single time (including myself).

Don't worry about corrosion. Aluminum corrosion is aluminum oxide, a very hard material that actually protects the aluminum from further corrosion.

If it was a steel frame, then I might worry about it. However, if it were a steel frame, you wouldn't have gouged it. lol


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## Strife21 (Apr 23, 2013)

Ha. Yea. Just kicking myself I am usually so careful. It was late and I was super tired and working in minimum light. Should have just went to bed and saved it for another day.


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## customfab (Jun 8, 2008)

There are millions of bikes with scared chain stays that have tons of miles on them. Props to your mechanic for filing off the burr. Go ride the bike, inspect it every time you lube your chain if you're paranoid about it.


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## Chris.S. (Oct 11, 2013)

If you were super concerned, a welder could dab a tiny bead on that spot, then with some filing and some paint the material could be restored to roughly it's original size/shape.


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## customfab (Jun 8, 2008)

Chris.S. said:


> If you were super concerned, a welder could dab a tiny bead on that spot, then with some filing and some paint the material could be restored to roughly it's original size/shape.


That would do more harm than good.


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## Strife21 (Apr 23, 2013)

I don't mind it bring visible. Only thing I was worried about was the frame failing cause of my stupidity.


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## Strife21 (Apr 23, 2013)

Here are some pics of it with the burr removed.


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## jtmartino (Jul 31, 2008)

As customfab said, you're fine. I have a few bikes with stuff like that - 'suck happens.


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## kjlued (Jun 23, 2011)

customfab said:


> That would do more harm than good.


yup


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## Strife21 (Apr 23, 2013)

Yup never even considered doing that so we are good. Thanks for all the help guys.


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## DaveRider (Jul 14, 2014)

Aluminum oxide corrosion does not protect it from further corrosion. It just keeps going deeper into the material.


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## TandemBear (Aug 18, 2013)

DaveRider said:


> Aluminum oxide corrosion does not protect it from further corrosion. It just keeps going deeper into the material.


Nope. Al oxide does INDEED prevent further corrosion. That's why aluminum doesn't "rust" like other metals.* Unless the frame is sitting in a corrosive solution, it will NOT corrode further. That's the magic of unpainted aluminum!

To the OP - WELL after the original post I realize - the LBS did the right thing, which was to reduce the stress riser you created with the deep scratch. The best thing to do is smooth it out so no deep grooves are left in the aluminum. Deep scratches facilitate crack propagation in aluminum. Filing, sanding and/or griding them out and smoothing the area pretty much eliminates the stress riser, although it does remove material, making it nominally less strong.

And as others have posted, you probably have more than enough material in the frame there as most frame builders anticipate chain suck/drop near the chainrings and subsequent damage. I've marred the crap out of my aluminum down tube and chain stays over the years without problem.

What you need to do is not worry about it and ride that bike! The biggest shame would be you no longer enjoying riding because you're worrying about this minor issue the whole time. Ride and enjoy.

*And for those of you tempted to point to the Enve carbon wheel/aluminum nipple corrosion discussion, don't go there. If Al corrosion was such a big issue (as some on the post have suggested), Al nipples would have been abandoned years ago. The posts saying basically, "This is normal. Al nipples corrode all the time. Don't use 'em in humid and/or coastal locales." are total BS. I've lived in the SF Bay Area all my life and have NEVER come across corroded Al nipples like those shown in that thread. Fifteen years at the LBS and manufacturer level and I never, EVER encountered corroded Al nipples. And I've seen my fair share of corroded bikes over the years. Front derailleurs rusted in place. Seat posts galvanically welded inside seat tubes. Sure, I've seen plenty of BROKEN Al nipples. Not too uncommon. But none like the nipples in the Enve thread.

Now I'm not saying the Enve aluminum nipple corrosion problem isn't a BIG deal (In fact, I'm amazed that ANY consumer who spends $3k for wheels would even BEGIN to accept that corrosion problem. Fix it or refund would be my stance.) But this problem is NOT Al nipples, it's the carbon rims, Stans, fluid interaction, or whatever, but NOT the nipples. Al nipples have functioned perfectly on thousands of bikes until the carbon rim/tubeless sealant usage came along. (And sure, forgoing the Al nipples is a very quick and effective solution. But that doesn't negate the fact that Al nipples are great on non-carbon/tubeless wheels.)

And then there's my bare aluminum tandem. No corrosion after 18 years of sitting around in "very humid" East Bay air. I even had a bunch of water sitting in the very well sealed head tube (King HS with ample waterproof grease) for three months (after a very rainy drive down the coast) and the frame was and is absolutely FINE. (The STEEL fork steer tube was the thing that suffered corrosion. But a few minutes of sandpaper took care of it.)

So enough about aluminum corrosion! Overblown hyperbole if you ask me.


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## fishwrinkle (Jul 11, 2012)

my ol lady has corrosive nipples


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