2011 TREK Marlin BBS02 Build: Chainring issues! Please help!

[bobfab]

HI Guys, Long time lurker first time poster.

I have taken the plunge on a BBS02 for my 2011 Trek Marlin. The install went fine, but upon test ride, it has been victim of chain-suck and is not mating the chain to the Bafang chain ring so well. I did buy a gauge and tested it, the chain was very stretched. I have since purchased a new one and it still seems to be binding up on the sprocket. Like the sprocket teeth are too tall or too wide or spaced too far apart. Any suggestions? I have contacted the ebay seller about this and they seem to think it is my rear sprockets that need replacing. Any ideas? I am stumped and cant be the first person with this issue...

thanks!

The bike:


Chain line / alignment looks decent:
\

old chain:


sample chainsuck:


new chain, better but still issues:


freewheel for reference:



any ideas?

[CoMoBiker]

It looks to me like the chainring is wider than the chain. Is your new chain a 7 or 8 speed chain and not 9 or 10 speed?
I'd measure the chainring width at the base of the teeth with a micrometer or good caliper and see if the teeth are under 3/32” in width. If it is a narrow-wide ring you’ll need to check width of 2 consecutive teeth.

[bobfab]

Just to follow up with this, the seller (ebay) gave me a sprocket that was not designed for this size chain (or really a typical bicycle chain). Got a new Luna CNC sprocket and all is well. I ended up buying another kit from the seller and the sprocket was different from this. very strange.

[TNC]

Just out of curiosity, can you tell us what kind of sprocket they sent you?...small motorcycle type, BMX, etc.?

[73Eldo]

I have only seen issues like that when trying to use some 'single speed' chains on a 'narrow wide' that can take the latest 11 and maybe 12 speed chains.