I have recently bought a Singular Gryphon build up as a singlespeed. I swapped the 16 tooth rear cog for an 18 tooth one and changed the chainset. I had to adjust the EBB as a result. Since doing this there is a grinding feeling like tight/mis-aligned bearings when pedalling with any pressure. It feels like it is coming from the BB but I can't be sure.

I have tried refitting the chainset in case I somehow did something wrong there but the grinding persists. I can't refit the old rear cog because I can't get the cassette lockring off with my DIY chain whip so a proper one is in the post but I can't see how it really can be that either.

Any thoughts?

maybe the chain is too tight?

old chain/new cog?
new chain/old cog?

Sounds like it's too tight to me. Chainrings aren't, perfectly round, is it at the same point in the chainring revolution?

APF

Does the chainset feel tight with the wheel and chain removed ?

Does the sproket and freehub feel tight out of the frame ?

If the answer is no then sounds like a chain issue

hope this helps

Thanks chaps.

The grinding happens with a slack chain as well as a tight one (I initially thought it was a tight chain causing the issue).

Chainset isn't tight without wheel and chain, neither is the sprocket/freewheel. And the chain was fine before I changed the chainset and sprocket.

I am waiting for a proper chain whip to be delivered (my chain + claw hammer usual bodge isn't working) and I will put a) the old 16tooth sprocket on and b) the old chainring on the chainset and see if the grinding disappears. Thanks for your thoughts though.

as sss,
old chain + new cogs. it'll quieten down after a ride or two. or change the chain out.

3/32 chain on 1/4 cogs?