The teeth on my middle chainring are kinda worn out and after replacing my chain the other day, I occasionally experience what's known as "chain suck". It really doesn't happen very often, in fact only in rare cases. But when it does, it's a mess.

Later this month, I'm departing on a 700 mile tour and am for the most part going to try to stay out of the middle ring. I don't know if I can budget a new chainring. So in the case that I do use the middle ring, I would like the assurance that I'm not going to damage my frame.

I've heard of some people using zip-ties on the chainstay. But I'm wondering, does the zip-tie method just protect the frame? or does it help prevent chain suck from being a big issue altogether(keeping the chain from getting stuck)?

Any other advice on what I should do?

You can get chainrings for £10 (about 15 USD)

Your going on a 700 mile tour on a bike that is not in top shape? First check the inside of your chain rin for burrs. it does not take much to get a chain to hang like that. I see it often in mtb.

Chain suck on worn rings is related to the same cause as chain skipping on a worn cassette. There's not much you can do to prevent it, short of using an older worn chain, or a new ring. protecting the chainstay with zip ties, or a metal guard isn't about preventing suck, it's only about protecting the stay from damage.

Steel frames are somewhat resistant to chain suck damage, but aluminum and CF frames can easily be damaged, so do what you need to protect them.

Meanwhile, skip a few beers in the next weeks and spring for a new chainring.

the clever small MTB builders made a piece that bolted under the chainstay and filled in the space the sucked chain into..
so didn't cure it, but made the damage caused to the frame, minimal..