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Yesterday a coworker insisted electrical tape on his chainstay was necessary, as "[he] gets so much chain slap [he's] literally snapped frames".

Now there's a couple dubious aspects to this--but my question is simply: can chain slap result in structural damage?

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5 Answers 5

up vote 5 down vote accepted

YES and NO

Depending on the type of frame and type of riding you are doing it could be a problem.

YES (you might have a problem)

  • If you have a steel frame slapping of the chain can damage the paint which is very important in keeping oxidants like water and air away from the bare steel. Steel will rust and eventually fail catastrophically.

  • If you have a composite mountain bike frame, chain slap can damage the outer layers of fiber which generally carry the most load. Nicks made by the chain in the frame's resin could be propagation sites for cracks that can lead to delaminating and failure. If you are missing or have worn through the factory included sticker guards, I would apply some type of wear guard.

NO (It won't be a problem)

  • If you have aluminum, stainless steel or another relatively non-corrosive metallic frame, no amount of beating with a chain is going to cause the thing to break. Aluminum and stainless steel are ductile materials and are very hard to damage without hitting them very hard with a large mass or by using some type of lever to bend them.

Probably No...

  • If you have a composite road bike, chain slap can damage the outer layers of fiber or could cause cracks in the frame as well, however the likelyhood of this happening is very small. Composite frame manufacturers generally include one ply of weave fiber on the lower chain stays to increase the durability along with a plastic sticker which should be more than adequate for many years of riding.

For what it’s worth I have <14 lbm composite road bike and I would never think of adding electrical tape (I’m counting grams here) for something as silly as chain slap.

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It should also be mentioned that if you break a chain, you're far more likely to bust a rear spoke than your chainstay. I've also seen old innertube applied to chainstays as slap gaurds. –  memnoch_proxy Aug 4 '11 at 5:17

Generally if you're getting anything other than occasional chain slap against the stay there's something wrong.

Eventually chain slap would wear away the paint on a steel frame and allow it to corrode through (if left out in the weather).

Some very light/exotic frames could in theory have such thin tubing that you could wear through, but only after a considerable period of time.

But I've never seen any damage (beyond scratches) due to chain slap.

I'd be dubious too.

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The only situation in which I could see that being the case would be with a carbon MTB frame, a rider who is using it far beyond it's intent, and a poorly set up drivetrain.

In that situation, you might get enough force from chain slap to ding the frame, and if repeated often enough, those dings might turn into a crack.

I seriously doubt it, but it could happen, in theory.

In the case of an aluminum or steel frame, No way, no how, not gonna happen.

Edit: I hadn't thought of eventual corrosion, in the case of steel. I suppose that is also possible.

Still not going to "literally snap frames" from chain slap. Nor would electrical tape prevent it, if it was going to happen, in a different universe, with different physical laws, or something like that. Dubious is one word for it. The other comes from the hind end of male cattle.

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YES!

I have had frame damage occur, but it was not from chain slap alone! As Daniel mentioned, it was on a steel steed, that led to corrosion. In fact it was on the very first bike in which I was totally smitten, a Ritchey P-23 :( Sadly, the chainstay did crack. Ritchey did repair, so all was not lost.

The term ridden hard and put away wet...yep on steel frames with chain slap or any paint chips for that matter is not a good idea! Most of us keep our bikes in a garage or in basement rampant with moisture. The MIT (most important thing) is to dry your steel steed!

Over the years I have seen this numerous times and just saw an old Serrota at the LBS with major rust to point where the shop was not going to do any repairs because failure was imminent.

Most of my riding is in RI, along the ocean, so that may accelerate the corrosion.

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Interesting. I've seen a few bikes (maybe 6) rusted through, but they all (close as I can recall) had failures of the top tube or down tube. (A couple were still being ridden in this condition, after application of duct tape.) –  Daniel R Hicks Aug 3 '11 at 21:26

I use only thick electrical tape on my frame.

and my freewheel was crap, practically not freewheeling at all. when I opened it up to re-oil it, it was completely dry. Also the rear derraileur was not adjusted in some 10yrs, and the cable had one split cable that was holding it all up when upshifiting. So i bet this is the worse it can get (only good thing was that the chain was new). And still i hardly have any mark on the electrical tape.

of course, that's all just my limited experience.

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