I’ve tried everything I can think of. When the chain is on the small chainring I get a grinding noise on every hard pedal stroke. No noise when I do a soft pedal stroke and no noise at all on the large chainring. Doesn’t matter what the rear cog is and I’ve moved the front derailleur up, down and sideways. I’ve also tried different pedals. Any ideas?

Is the inner chainring bent at all? Sounds like deflection when working hard.

I’d check the bottom bracket bearings and cups for wear,, and the rear wheel’s bearings as well. I had issues with the pre-load on both of these bearing locations allowing them to loosen and cause grinding of surfaces due to play.

Semper Fi bro👍
Bill

A worn chainring with a new chain will produce a rumble felt and heard, which gets more intense as pedaling force increases.

You can file away the forward-facing hooks from the driving side of each tooth to eliminate the noise entirely.

A 1mm bevel to the sharpened corner atop each tooth usually prevents the chain's rollers from contacting the corners during both the engagement and disengagement events as links fall into and out of mesh with the worn chainring on every revolution.

I have fixed many chainrings this way and it's almost always the small chainring that needs it.

do I see daylight under the chain?

doesn't look like the chain is evenly seated across all the chainring teeth.

for grins, check the security of the chainring bolts.

How about some good photos of the small ring?

After replacing the chain, I rotated my small ring a bolt hole or so, hoping to even out the wear, but instead I created noise problems, and I eventually replaced the ring.

Chainring bolts tight, chain is fitting on the ring fine.

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another possible contributing cause could be a torsioned chain

you could demount chain and let it hang loosely to check for a torsioned section


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Photo of back of chainrings in post 9 shows badly worn teeth on the smaller ring and moderate wear of those of the outer ring. Notice that the troughs between the teeth of the inner ring are longer and more asymmetrical than those of the outer ring.

I'd replace both rings, but you might be able to get away with replacing just the inner ring for a season or two.

I’m going to blame it on the Regina chain. I pulled the cranks to inspect everything. Checked the bottom bracket to make sure it was tight. Then a stuck a narrower chain on it. No more noise, I’m wondering if the Regina was too wide.

That particular Regina is pretty wide, and that extra width contributed - but I agree with Trakhak : the "shark tooth" profile on the inner ring teeth dictates immediate replacement.

DD

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wrt shark tooth profile -

since the chainwheel's dentition is cut from the centre of the stock you can double its life by reversing it

the bushings will protrude one mm or so above the face of the chainwheel but all else will be the same...


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I had the same symptoms with a worn out chain. I had just bought the bike and it hadn’t been ridden in quite a while . the FW was for racing so I replaced it with a more touring set up. The chain rings looked very good and I did not check the chain before I cleaned and lubed it . Every thing was cool on the stand and when I was just cruising. When I accelerated or climbed I got a grinding feeling. I had already serviced the bottom bracket . I took it apart again and meticulously cleaned and greased the bearings and put it back together with proper adjustment. Finally I gave up after 3 or 4 short rides and took it to my favorite LBS. The first thing they checked was the chain, yup! I bought a new chain AND a chain gage. Bike rode smooth as butter.

Have you determined where it is rubbing? Hard pedaling in the small ring will cause the chainstays to deflect, which in turn can cause the chain to rub on either the front derailleur or outer ring. If it is the front derailleur that is rubbing, a little trim can fix that. If it's rubbing on the ring, that will be harder to address, and you may just have to live with it or avoid hard pedaling in the small ring.