worn chain-ring

[Number_35]

Winter here is hard on the chains on our fat bikes, with lots of salty slush on the roads. I checked the chain on my wife's bike a couple of days ago and found it to be stretched beyond 1%. Yikes!

The folks at the bike shop were clearing out some German-made Connex chains they'd discontinued, so I bought a couple for a pretty good price. The regular price was C$64.99, and the sale price was C$30. Not bad. Connex's magic link is interesting - it's asymmetrical, and can be undone by hand quite easily, no tools required. The only downside is that it does have to be installed one way, with the gently-curved side interfacing with the chain-rings and cassette gears. The chain is brass-plated, and looks quite sharp.

Based on my experience with my wife's mountain bike in September, I also changed out the rear cassette. When I test drove the bike, it rode and shifted perfectly, but today my wife complained of the chain binding or locking up. I rode beside her, and, sure enough, I could see it binding and then popping free as it came off the bottom of the front chain-ring. She was using the small (22T) ring, whereas my test ride had been with the large (36T) ring. She shifted up to the large ring, and we got home OK.

I transplanted a used 22T off an old Shimano crankset, and it looks like it will work fine. The bottom bracket was pretty notchy as well, so I repacked the bearings with fresh grease (Mobil 1 red, because this is BITOG). The external bearings used in the FSM system are interesting. There are only about a dozen very small bearings per side., but it seems to work OK. My Pugsley uses the same system.

Anyway, here's a photo of the culprit - experts, do you agree that the teeth look pretty pointy? I guess the small chain-ring takes quite a beating compared to a 32 or 42T.

 

[AZjeff]

Small ring wear has less to do with road grime and more to do with the forces you put on it compared to the big ring. Combine the lower engaged tooth count and the force you put on it grinding up steep hills and you can see why the little ring wears out faster.

The 36T engages 18 teeth as you pedal while the 22T engages 11 teeth. We favored steel little rings, bit more weight but last longer.

 

[Number_35]

I think the road grime wore the chain which then wore the small ring. And yes, I never wore out the 52T chain-ring on my late great Norco Bigfoot (1984, 3 x 5 speed).

Agreed, the 22T chain-ring is actually equivalent to the middle gears on the 9-speed cassette (11/34), and will likely wear even faster, as it gets a lot of use in winter.

 

[buck91]

I also doubt road grime has much to do with it. Yes, small rings wear faster than large rings but the main culprit is likely excessive chain stretch. Might want to check out your cassette, also.

That said, what I have noticed with road grime and small rings is that a dirty chain will suck MUCH easier than a clean/lubed one... at least on rigs that have been prone to chain suck.

Edit: Sorry, to address the OP's question. Most people agree anything short of extreme cog wear is difficult to tell by eye. What I've found most indicative has beeen to look at the bearing surface of the teeth. Are they scalloped (for lack of a better term)? If you see a noticable concavity to the bearing surface of the teeth then it likely is worn. To my eyes that ring doesn't look worn enough to judge it visually.

 

[AZjeff]

I've run some pretty hooked small rings, that one doesn't look bad but the problem was the new chain being tighter and the stretched teeth not letting the chain go.

 

[Number_35]

Originally Posted by AZjeff
I've run some pretty hooked small rings, that one doesn't look bad but the problem was the new chain being tighter and the stretched teeth not letting the chain go.
Yep, it's the new-wine-in-old-wineskins issue with a new chain and old gears. Agreed, I'm not good at spotting a worn chain-ring or cassette gear, but this one looks like it's starting to sharktooth, usually a sure sign.

A friend uses three different chains, rotating them every few months so as to minimize the wear on the gears. Works well for him - I should do it as well.


Originally Posted by buck91
I also doubt road grime has much to do with it. Yes, small rings wear faster than large rings but the main culprit is likely excessive chain stretch. Might want to check out your cassette, also.

That said, what I have noticed with road grime and small rings is that a dirty chain will suck MUCH easier than a clean/lubed one... at least on rigs that have been prone to chain suck.

Edit: Sorry, to address the OP's question. Most people agree anything short of extreme cog wear is difficult to tell by eye. What I've found most indicative has beeen to look at the bearing surface of the teeth. Are they scalloped (for lack of a better term)? If you see a noticable concavity to the bearing surface of the teeth then it likely is worn. To my eyes that ring doesn't look worn enough to judge it visually.
Excellent point - perhaps in dry weather this would not have been an issue. In any case, 'chain suck' sure seemed to be an issue earlier today.

 

[anndel]

I have Connex on all 3 bikes - 2 road and 1 mtb. They shift perfect except my wife's mtb but it's the derailleur. Just have to clean the chain and cassette frequently and lube the chain. The photo shows a worn chain ring so it or maybe the entire cassette should be replaced.

 

[NYEngineer]

What is that, 64 BCD? I would have suggested Wolftooth stainless or Surly stainless but neither makes that size.

I have a 24 tooth Surly stainless on my Surly OD crankset and it's been stellar. Honestly, I'm not on it a lot. Even the 33 tooth is wearing very well. I'll look around a little and see if I can find anything good.

 

[NYEngineer]

I found an Amazon seller called aMTBer who makes a hardened stainless 64 bcd ring with 20 or 21 teeth for about 35 bucks.

 

[Number_35]

Originally Posted by NYEngineer
What is that, 64 BCD? I would have suggested Wolftooth stainless or Surly stainless but neither makes that size.

I have a 24 tooth Surly stainless on my Surly OD crankset and it's been stellar. Honestly, I'm not on it a lot. Even the 33 tooth is wearing very well. I'll look around a little and see if I can find anything good.
I learn something every day (and love doing so) - looked up BCD - 'bolt circle diameter', easily measured on a 4-hole ring like this, centre-to-centre on opposite holes, and came up with about 64 mm. Good eye!

The original says 'WCO62-22T' on it (which I missed capturing in my photo). I assume the manufacturer is WCO, but I can't find them online. Would 62 be the nominal size? Seems weird if 64 mm is a standard size. This chainring may the factory original - the bike is a Charge Cooker Max from c. 2014. (I bought it used in 2015 from a bike shop owner who had received a factory sponsorship from a competitor, and thus had to sell the Charge.)

As far as the replacement, I cheaped out and installed a used one I had in the parts bucket. I like the hardened stainless idea though! We'll see how the salvaged one holds up.

 

[Kamele0N]

Originally Posted by Number_35
I checked the chain on my wife's bike a couple of days ago and found it to be stretched beyond 1%. Yikes!


For you....@2:50...stretch is different for different setups

 

[Number_35]

Thanks, great information! I have the ParkTool CC-3 chain-stretch measurement tool, which is calibrated for the older chains - it measures 0.75 and 1.0% stretch (with no provision for 0.5%), which is fine for the 1-, 8-, and 9-speed chains our bike fleet is equipped with. Per the video, 0.5% is a standard for the newer 11-speed chains, and the CC-3.2 will measure 0.5 and 0.75% stretch.

I am OCD enough about my bikes that perhaps I should get a CC-3.2, and rotate chains once they hit 0.5% stretch.

My beloved test rode her fat bike with the new-used 22T chainring, and reported great improvement but still some occasional skipping under load. I bought a new Shimano 22T chainring from our closest LBS, and installed it. The packaging identified it as appropriate for 3 x 9 application. The fat bike is 2 x 9, but the Shimano was the closest they had. Lots of snow and no riding today, so no verdict yet. If this chainring doesn't work out on the fat bike, I can use it on one of the mountain bikes.

 

[Kamele0N]

Dont forget that many chains nowadays are directional... Like Shimano HG-X...