Chainstay question

No question is dumb. It's a pretty common thing for this to happen on modern bikes. With the huge range of gears we have available, I think it would be tough to put a strong enough spring in the rear derailleur to hold the chain tight. There are several solutions though. The cheapest (and one I use) is a section of an old tube wrapped around the chainstay and the ends secured with electrical tape or a couple zip ties. You could also purchase a chainstay guard made from lots of different stuff (neoprene, carbon fiber, etc) from just about any LBS or online bike store. One of the most popular brands is Lizard Skins if that helps your search.

i've never had such a problem in 30+ years. maybe your chain is too long, if you're a short rider with very short chainstays. or perhaps you could go with a longer cage on your deraillieur

philso said:

i've never had such a problem in 30+ years. maybe your chain is too long, if you're a short rider with very short chainstays. or perhaps you could go with a longer cage on your deraillieur

Fair enough, but the rest of the modern world have had those problems.

Claes said:

Fair enough, but the rest of the modern world have had those problems.

perhaps you're right. my newest bike is already almost 5 years old. maybe i need a more modern one. i'll look for one where the chain rubs on the stays when i take it out for a test ride.

after i buy it, i'll shorten the chain or get a longer cage rear deraillieur

philso said:

perhaps you're right. my newest bike is already almost 5 years old. maybe i need a more modern one. i'll look for one where the chain rubs on the stays when i take it out for a test ride.

No, you actually have to ride it for that to happen, leave it inside and do not ride it, just like you do now, a new bike will make no difference, so save your money.

Claes said:

No, you actually have to ride it for that to happen, leave it inside and do not ride it, just like you do now, a new bike will make no difference, so save your money.

sorry to pop your bubble, but i'm on my bike close to every day, rain or shine, unless i'm sick or something, be it around town or on tours of up to over 3,000 miles. i don't think anything of going 30 miles or so just to do some grocery shopping.
i've ridden many sets of chains, chainrings and rear clusters to the point of serious chain skip over the years but, as i stated simply before, i've never had a problem with chain rub on the chain stays.

in addition to bmph8ter's obvious solution, i suggested that shortening the chain somewhat or getting a longer cage might help. what's to get so snooty about in my original post?

if you've got any useful suggestions for the guy, how about posting them

philso said:

i've never had such a problem in 30+ years. maybe your chain is too long, if you're a short rider with very short chainstays. or perhaps you could go with a longer cage on your deraillieur

A longer cage would lengthen the lever arm and, if the spring strength is constant, would actually reduce the tensioning of the chain. In my experience, triple chainring bikes with long cages have more chain bounce than double chainring bikes.

that's an interesting observation and possible correct. i don't know whether manufactures use the same springs on both long and short cages or if they use ones of different strength.

trying to visualize what's happening, i'd guess that the rubbing is happening obviously above the chain stay, probably while on the granny and smallest cogs, and while not pedaling or, pedaling backwards. while pedaling, there's obviously no slack in the chain above the stays so, they shouldn't actually be rubbing while pedaling.

Andrepaul, maybe place your chain on both smallest cogs, take up the slack by turning the pedal forward, and see what sort of clearance you have. at the same time, check and see if your deraillieur is taking all the slack or not. if there's still slack, that's a problem.

after that, put the chain on both of your biggest cogs. is the deraillieur maxed out? if not, you can afford to remove a/some links from your chain, which should help.

if your deraillieur is taking up all the slack while on the smallest cogs, and close to being maxed on the largest cogs, then either covering your stay and/or trying a larger deraillieur which will wrap up more chain are the only 2 possibilities i can think of.

hope this helps

philso said:

that's an interesting observation and possible correct. i don't know whether manufactures use the same springs on both long and short cages or if they use ones of different strength.

trying to visualize what's happening, i'd guess that the rubbing is happening obviously above the chain stay, probably while on the granny and smallest cogs, and while not pedaling or, pedaling backwards. while pedaling, there's obviously no slack in the chain above the stays so, they shouldn't actually be rubbing while pedaling.

Andrepaul, maybe place your chain on both smallest cogs, take up the slack by turning the pedal forward, and see what sort of clearance you have. at the same time, check and see if your deraillieur is taking all the slack or not. if there's still slack, that's a problem.

after that, put the chain on both of your biggest cogs. is the deraillieur maxed out? if not, you can afford to remove a/some links from your chain, which should help.

if your deraillieur is taking up all the slack while on the smallest cogs, and close to being maxed on the largest cogs, then either covering your stay and/or trying a larger deraillieur which will wrap up more chain are the only 2 possibilities i can think of.

hope this helps

They do use the same springs for both cages, so a longer one will in fact have a lower chain tension. The phenomenon that you've not observed, but has been common on every bike I've ever ridden is that the chain slaps against the chain stay when it goes slack during a shift. It doesn't rub. And it has nothing to do with modern bikes. There are a lot of classic frames with chromed chain stays for exactly this reason. If you start pulling links out of the chain and messing around with spring tensions you're going to waste a lot of time and probably not solve the problem. Just wrap the chain stay with some electrical tape.

artmichalek said:

They do use the same springs for both cages, so a longer one will in fact have a lower chain tension. The phenomenon that you've not observed, but has been common on every bike I've ever ridden is that the chain slaps against the chain stay when it goes slack during a shift. It doesn't rub. And it has nothing to do with modern bikes. There are a lot of classic frames with chromed chain stays for exactly this reason. If you start pulling links out of the chain and messing around with spring tensions you're going to waste a lot of time and probably not solve the problem. Just wrap the chain stay with some electrical tape.

Exactly what I was going to say but you beat me to it. I think what the OP is referring is what is often called "chain-slap" and rubbing really doesn't describe it correctly. Like you said it's the chain slapping the chainstay when the chain is slack (during a shift, etc.). If the chain actually is rubbing the chainstay on the inside, that's something entirely different and I (like philso) have never experienced that before.

There are several chainstay protectors on the market that do a good job. Like you said, electrical tape is a cheap solution. Adhesive backed grip tape works too. A cheap and inconspicuous method that I use is clear duct tape. You can get it at the hardware store. It's very durable and not very noticable after you apply it.

Cool..thanks dudes!

Here's a good habit to get into...
When your ride is over, leave the chain on the small chainring and the smallest cog. This relieves the tension on the rear derail spring.
You really don't want that spring sitting there in the stretched out position.

BikeyGuy said:

Here's a good habit to get into...
When your ride is over, leave the chain on the small chainring and the smallest cog. This relieves the tension on the rear derail spring.
You really don't want that spring sitting there in the stretched out position.

You're kidding right? Unless you're storing your bike at severall hundred degrees C, the spring isn't going to creep and lose stiffness.