Swapping cranks on my 1x8, but the chain is not fitting onto the chainring properly - its super snug and once you get about 1/2 around it stops fitting into the teeth, and the links that do drop in often jam up and don't pull off.
Here's a pic of what I mean where it stops lining up:



I'm trying to put on a Origin8 SS crankset - the one I received 2 weeks ago ended up being a 1/8 chain version - I didn't notice that when buying it and I had THIS exact problem. I realized I hadn't ordered the 3/32 chain version, so I found it on amazon, ordered it. It arrived, and the box says 3/32 as well (the UPC/price tag does anyway). But as you can see I am having the same problem.

Did I get sent another 1/8 version in a mislabeled box? Is that even the problem? What would cause this?
For reference I am using the same chain I was using before with the previous crank without issue, which is a Sugino RD2; which is 3/32.

I just want to get this bike finished so I can sell it. Send help.

Thanks

Old chain? Maybe the rollers aren't moving freely with just hand pressure and they are pushed to one side making it look like the chain i too short between links.

The chain is about 6 months old.

Time for calipers or micrometer. What's the thickness of the chain wheel near where the roller would bottom out? What's the inside measure between the inner chain plates?

1 X 8. Narrow cogs. You have an 8-speed chain and that is a chainring for a basic 3/32" chain as was used for the old 5 and 6-speed freewheels. (Single speeds and fix gears use 1/8" or 3/32". The 8-speed (an d 7-speed) cogs, rings and chains sometimes get loosely called 3/32" but are in fact narrower and not interchangeable.)

I could be wrong, but my donut is in this.

Ben

Guys, what I'm seeing isn't the chain too thick or thin, it's the chain pitch is too short for the chain ring. Maybe measure 24 links (about 12 inches) and make sure that the chain pitch is right?

+1 on it looking like a chain pitch issue. Pitch is the distance between pins. However, I thought all bicycle chain was 1/2 inch pitch so I'm a little baffled.

I was going to post earlier but gave it up. Now I see my point being mentioned by WizardofBoz. The chain looks to seat well on the ring teeth in the upper right corner of the photo. But it's the pitch mismatch causing the ride up of the chain. First thing I thought of is to test fit the ring onto a know chain and the chain onto a known ring. Andy

If the chain measures correctly with a 12 inch ruler and it fit the Sugino RD2 crankset and the 8 speed cassette then I would suspect the new chainring.

This is the crank I just took off that has been used since I built the bike: https://www.retro-gression.com/products/sugino-rd2-crankset-silver

If memory serves, I put a 1/8 SS chain on the one I had last week as a test and it didn’t have this issue but the chain was too wide for the cassette and the derailleur.

But yes, basically the chain seats properly for about 1/3 of the chainring then starts to mismatch and it won’t fall between the teeth like shown at the bottom of the pic.

This is the crank I’m trying to put on: https://www.origin8.bike/product/trac...rankset-210491

Nothing to add other than I had this same problem before when putting on a new chaining onto a crank. Didn't seem like it was a width issue and the chainring was new and the chain was working fine with the previous chainring. If it was chain stretch shouldn't it appear to be too long rather than too short?

I'd say 79pmooney has the answer. Pitch is standard so it ain't that.

Agreed it is not a pitch or "chain stretch" issue. I've used 8 speed chains on my 3/32 SS chainrings all the time. That chainring is made for 1/8" chain.

So you think they sent me a mislabeled box, as I suspect.

Like ​​​​​Iride01 posted earlier, you have to measure it. That's what a science guy would do! Even looking at it very close while comparing to a known 3/32 ring would likely show it is too wide, I suspect. Let us know what you find.

I cropped your photo and point to the link where I thought it looked like the roller was pushed to one side and hitting the tooth below it which forces all the other links to sit away from the tooth below them.




Also..... is the chain directional? Is that supposed to be the outward facing side and as well is the number on the side plate upside down? Though I don't see any shape differences in the opposites sides of the plate. Besides, that is generally for shifting improvements and I wouldn't think it would affect how the chain sat. 8 speed chain though, probably didn't do that then.

You got a quick link for this? Finish installing it, ride it down your driveway and back, then look at it.

To the OP: Can you post a picture of the top of the ring where the chain is seated well?

Here's the chain, FYI: https://www.amazon.com/SRAM-P-Link-B...9208047&sr=8-1

No I don't believe its directional. I put it on the previous crank (linked to in post above) without any specific orientation and it has been fine for 6 months.
I never finished installing it because it didn't seat properly for the majority of the chainring. When putting it on it will look ok for about 1/5 of the chainring then start to be off a little. If you force it down in then the chain just sticks in between the teeth and doesn't release back out. I don't think I could install it so that it's even rideable.

I also don't want to damage it so that I can't return it. It's already cleaned up and back in the box.

Are you certain you can trust the place you bought it from not to be some kind of look-a-like that looks great in finish, but maybe was off in tooth pitch?

Never found a bargain for bike parts on Amazon. If I did, I'd be leery of what I was getting. If you paid normal markup, then it's probably trustworthy.

I'd have to believe the original stuff you have is probably correct. Chains are pretty standard things. The difference in pitch is going to more on the order of .25" or maybe .125". So you'd know quickly with even the most inaccurate ruler you can find, if the chain is wrong.

It's a regular stock Origin 8 product, just from whatever seller is using Amazon to sell it. Sometimes it's from a bike shop using Amazon storefront, or sometimes it's Amazon warehouse stock.
The previous crank is from Retro-gression, and is a Sugino so that's definitely trustworthy. But I have no reason to question the quality of the Origin 8 product either, I've always had good experience - I just think I'm getting mislabeled boxes since they make both a 1/8 and a 3/32 version of the same crank.

Well, we can't measure it for you. My shimano ultegra and 105 chain wheels measure about .083 down near the bottom of the notch. My RaceFace Cadence is even narrower. So they are well under 3/32" (.09375").

Do you feel you put enough pressure on the chain when you put it on to move the rollers to position? Sometimes the rollers on a link will take some pressure to pop them back to where they need to be.

"One accurate measurement is worth a thousand expert opinions." Admiral Grace Hopper

OK I will get out my calipers - what am I measuring? The distance between the chain pins, or the distance between the teeth on the ring? If that, what height on the tooth do I measure?

Thickness of the chain wheel down near the bottom of "U". That's what you've been wanting to know, whether they sent you a crank for a 1/8" instead of for a 3/32" chain.

OK, I busted out the calipers and here's what I found. For the most part, it was registering 15/128, but I did get it to read 1/8 as well - so I think that answers that. It's a mislabeled box. *shakes fist*
Thanks for the help and insight, y'all.