Igualmente

Hi,

I've noticed two things on my less than a year old road bike.

1) When on the small chain ring (34T) and smallest cogs (12, 13 T) the chain is rubbing on itself in the area of the rear pulleys (the chain feeding into the pulleys rubs on the chain running through the pulleys). Driving the B-screw in all the way doesn't resolve it.

2) When the chain is on the large chainring (50T), it seats properly only on part of the chainring. For the middle third of its travel around the chain ring the chain is seated properly (each link sits fully on the ring). For about the first and last third of its travel on the chainring, the links do not sit fully on the ring.

Neither of these issues existed before.

I think these are symptoms of chain stretch. This is surprising to me as the bike is just under a year old, has seen less than 3000 km in use and I am not a big powerful person. I guess I'd like to confirm that I'm seeing a stretched chain that needs replacing and ask if the cheaper ultegra or KMC x10 chains would likely last longer.

Thanks!

dsbrantjr

Get yourself a ruler and measure the chain. Chain Maintenance Don't mess around with those chain checkers.

Kopsis

Sounds like your chain is too long (too many links, not just wear). How much extension do you get on the RD cage when you shift to the big-big combo? You may have been just borderline before and now a little extra wear is pushing it over the edge.

mconlonx

Wear is not just a function of age, also depends on maintenance -- how often do you lube the chain? -- and conditions -- wet weather and/or particularly gritty environment.

1) Check chain length, as Kopsis suggested above.
2) Check chain wear with ruler or appropriate tool -- a shop would probably do it for free.

RISKDR1

do you have horizontal drop outs with some adjustment? You may want to back it out to effectively lengthen the wheel Base by a small amount. That may get you back to correct chain length. Of course this is not a cure for a stretched chain if it truly is stretched beyond tolerances.

FBinNY 

Chain stretch is unrelated to your issues.

First of all, chains don't stretch enough to create the overlap at the pulleys. Extreme chain stretch of 1% or so (twice the normal replacement guideline) would only add 1/2" to the length of a chain. As noted above, it's possible that your chain is an inch 2 long and could be shortened to solve that.

Secondly, if the chain were the problem, the fit on the chainring would be uniformly sloppy. Since it varies, it's more logical to suspect that the chainring itself is unevenly worn, which is normal, and it's likely too soon to fret over it.

Of course you could (should) actually measure the chain for stretch as suggested above, but that's separate and distinct your problems.

Igualmente

Thank you all for your answers.

I measured the chain (with 2 different metal rulers, twice each) and consistently get about 3/32" of chain stretch (that is, what should be a 12" section between two pins measures between 1/16 and 1/8 too long).

As far as chain length, when on big ring, big cog, I can fairly easily overlap one link above another (making a kind of Z in the chain). The RD still has a lot of slack (i.e. I can rotate it a long way forward as one pulley is below and about 1/2" forward of the other.

The chain has seen almost exclusively dry service on pavement (no wet days, no gravel riding). I've cleaned it with a park tool device and relubed twice with finish line ceramic wax. That included cleaning the cassette and chainrings. I'd say the chain has seen less than 2500km, about 1/4 to 1/3 on rollers.

Lastly, I don't have horizontal dropouts, so the wheel axis can't be moved much.

Seems like a chain replacement (with at least one less link) is called for?

fietsbob

Were the chain wheels worn, or they new, Too?

FBinNY 

Yes, and it's about 50:50 whether the new chain will run on your cassette. If the new chain skips, you have a choice of buying a new one now, or putting the old chain back on to squeeze a few more miles out of this one.

However, you're getting extremely short chain life (is there such a phrase as very extremely?). Without knowing more, I suspect the cause is related to how you're cleaning the chain, and suggest you give up the washer, and dry wipe the chain as clean as possible between lubes.

Igualmente

OK, thanks FBinNY.

Fietsbob: not sure what you mean, but the whole bike was new 2500 km ago and nothing has been changed out in the "drivetrain".

Kopsis

Definitely too long. Assuming you're going to replace it, I would cut the new chain at least two inches (4 links) shorter than the old one. You can probably go even shorter than that (google for big-big chain sizing) but that much should at least solve your RD pulley interference with no risk of being too short.

If you're going to use a chain cleaner, you need to make certain that the internal bushing/roller surfaces are completely dry of solvent before applying lube. This is especially critical when using a "dry" lube (a wet lube will continue to flow to interior surfaces as any residual cleaner dries our or is flushed out).

Igualmente

Thanks for all the tips on cleaning the chain. I did wipe off moisture and leave it to air dry for a couple of hours after cleaning, but perhaps overnight would have been better.

ThermionicScott 

If you're using a water-based cleaner, it's best to heat the chain after rinsing so that it has less time to rust.

elessar007

Chain is too long, as others have noted. You need to remove some links. Start with one pair (inner plate link +outer plate link) and if thats not enough go to two pair. Its easier to start small and do it twice then to go big and wind up taking too much.

When doing your cleaning of the chain, if you are going to allow it to air dry before lubing with a dry lube, try and remove as much of the material as you can. I use a heat gun on low to dry out all the water drops hiding between pins and rollers. If you have an air compressor, blow it out. Put it in the toaster oven on 'Warm' if you wish. Point is, the less moisture, the less chance of surface rust.

Kopsis

As others have said, heat is your friend when it comes to getting the cleaner out of the chain. The little gaps hidden inside the rollers are good at retaining both oil and solvent. The only surface for evaporation is the tiny gap between the roller and the side plates. Using enough heat to flash off the solvent (transition it to vapor phase) is the only reliable way to force it out. For water-based solvents that's going to be somewhere above 100C. Petroleum-based solvents vaporize lower (~85C), odorless mineral spirits higher (~150C). Be careful with heat sources and ventilation if using anything other than water-based solvents as you don't want to breathe or ignite the vapor.

I use a "wet" lube and lube much more frequently than clean -- typically on the order of 5 - 10 lubes for every one cleaning. In most cases, cleaning's only significant benefit is cosmetic, so do it sparingly if you want to maximize chain life.

ThermionicScott 

One of the benefits of organic solvents is that they won't cause rust while you wait for them to evaporate, so there's no need to "cook" out the leftover solvent. I just hang mine up on a nail overnight and it's dry as a bone and ready for lube the next day.

Igualmente

Well, clearly I should do something different. Maybe treat it like the chain on my 1997-ish 8-speed MTB that has been properly cleaned twice (maybe), is lubricated when it starts to squeak and has seen all manner of dust and dirt on and off pavement and while towing children in a trailer off-road up steep hills. It has an original chain that shows less than 1/16" stretch. Just kidding, of course. I will keep in mind all the above excellent advice and do something different.

randomgear

Running on the small/small or large/large combinations are called cross-chaining and should be avoided as it does twist the chain and may lead to excessive wear of the chainrings, the cogs, and the chain.

Igualmente

I thought that cross-chaining is less of an issue nowadays. I don't stay in the cross-chained gears once I realize I am in them, but don't spend a lot of time worrying about them.