Chris O

Hi All,

My Ultegra 6800 Chainrings have about 8000 miles on them. I'm going to replace the chain soon and wondering if the chainring teeth are worn enough to warrant replacement at the same time. A closeup pic is below.
The shifting is still OK. Looks like just the R6800 outer chainring is about $150 to replace, but a new Ultegra R8000 crankset is $279, so maybe it makes the most sense to upgrade the whole thing given the bonding issues of the R6800 cranks? I've got the R6800 FD, but the Shimano compatibility chart seems to show they work together.

Not wanting to spend money when it's not needed, but willing to invest if it makes sense to maximize the life of the drivetrain as a whole.

Andrew R Stewart 

Chain ring wear won't add to chain wear much (assuming alloy rings). So replacement is usually driven by chain skip, chain drop and chain suck issues. But rough chain/ring teeth engagement can motivate replacement too.

I would replace the chain (and cassette?) then evaluate how things are.

One thing I will add is that the teeth imaged do look like the chain was well worn. The sides of their valleys seem rather eroded. Andy

davidad

How often do you clean and replace your chain?

DrIsotope

Easiest in a stand: while the chain is on the big ring, grab it at around the 2 o'clock position and pull forward. If the chainring is a little worn, you'll be able to lift it a little, and see some light between the chain and the ring. If it's really worn, you might be able to pull the chain off of the ring entirely. You can also put a short piece of new chain (like the part broken off when fitting a new chain) on a selection of teeth and see if the chain can rock back and forth.

You can't really judge wear by cosmetic appearances-- modern tooth profiles look half-worn when they're new, and common anodization is between 0.0002" and 0.0012" thick.

blamester

This.

Chris O

I replace the chain when indicated by the Park chain wear tool at 0.5%, usually twice a year, and the cassette was just changed this spring. Tried pulling on the chain at the 2 o'clock position and there was a little give give, but I could not pull it up much, so I guess for now I'll keep using it. Thanks all.

fietsbob

laid a brand new chain on it to test tooth wear , yet?

HillRider

Chainrings are pretty tolerant of wear as the chain is "applied" to them under tension so they are much less likely to skip than equally worn cogs. Typically, they are also larger and with more teeth to share the wear than cogs.

It takes a lot to wear chainrings to the point that they skip or spill the chain.

dwsmartins

Maybe it’s a lot, but I managed to get the middle chainring skipping, despite cleaning and lubing the drivetrain often and also alternating between 2 chains. In fact, I guess it’s not that uncommon, as I’ve seen other cyclists have this problem too, particularly on the middle chainring.

Koyote

Assuming reasonable chain replacement and cassette replacement intervals, 8000 miles is nothing for chainrings. I’ve got about 20,000 and 30,000 miles, respectively, on my two oldest cranksets – and I’ve never even thought to check for wear. Now, if I were running a 1X, especially on a mountain or gravel bike in dirty conditions, I might expect to replace a chainring a bit earlier - but with a road double? No.

DrIsotope

I got right around 9k miles out of a Praxis Works 50T. When replaced, it was worn to the point that the bike made a creaky groan sort of noise every time I took off from a stop, as the chain slid up the worn teeth. I got almost double that out of a Praxis 48T previously, so this time around I figure I bear at least some of the responsibility-- I recall letting one pair of chains stay in use a bit too long.

andrewclaus

I'm also in the 20K+ mile school for chainring wear. I've only had one bike long enough to wear out a chainring. At that point it's just an annoying chain noise that doesn't improve with lubrication.

HillRider

My experience exactly. I have 27,000 and 28,000 miles on the cranks on my two most ridden bikes and they are still running and shifting well. I ride mostly in the "big" (50T) chainring and that also reduces the wear. As you note, a 1X with a small chainring ridden in abrasive conditions would be a far different story.