I'm unsure of it is. I mean I've seen worse chain rings but I don't know for sure. I don't think it's bad but would you change it?

Might want to clean it before pictures...

When I overhauled Frankenbike the chain rings looked a lot like yours...I changed them rather than wishing I had. I went from a 7 to 9 cassette as well to get a 32 cog...probably overkill, but it worked out okay.

Why are you asking? You don’t need to change parts that function properly. The grit encrusted chainrings suggest better and more routine maintenance, otherwise, if it ain’t broke, don’t fix it.

^+1 This. Clean rings good. Dirty rings bad!

^This.
I've only changed chainrings for 2 reasons:
a) Chainsuck. (Teeth wear to slightly hooked profile that won't release chain, resulting in lower chain shoved up into FD.)
b) Pins on backside of large ring getting rounded off, making shifting onto large ring impossible.

Of course the rings are worn, you used them after all...

Outside of the grime what I see is tooth wear from stretched chains. Andy.

Yeah so my thinking is, well I'm putting a new chain and a new cassette at the back. And this being worn I'm not sure if it's worn to the point where it'll induce accelerated wear on my chain and cassette. That's my concern imo

really, truly, deeply---clean your drivetrain more often, dont let it get all "erosion paste" like that.
wipe your chain down with an old rag every few rides, takes seconds, use same rag to wipe chainrings, rd jockey wheels, and rag floss the cassette once in a while--all this will go a long way to longer drivetrain life.

and learn to measure a chain over 1 foot to see how much chain wear has occurred, so that you arent wearing away stuff from an overstretched/worn chain.

Right. Will do.

It does look worn a bit. How does it operate/shift?

Often mistaken is the redesign of the chain ring teeth to ease, speed up, shifting ..for wear..

to know if they are worn, you compare a brand new chain laid around the chainrings.


or better still new cassette new chain (so you know they are fine) does the chain skip on the chainring teeth [still]?









....

I cant imagine a new chain will be skipping on those chainrings, they are not shark toothed at all.

sure, as noted, if some wear has occurred from too long chain left on too long, then it may affect a new chain, in terms of accelerating chain wear, but I guess the only way to know is to put the new stuff on and see.
I would guess that it will be fine.

and the whole "keeping the drivetrain clean ish" thing certainly does help wiht long term wear, but thats up to you. Generally, doing the regular , fast and easy rag wipe of stuff at least keeps the excess chain lube down, that always comes out on its own, and all it does is have dirt stick to it, and makes the gunky, gritty paste that was on everything.

As some other have said, if they aren't giving you problems, then it isn't necessary to replace them. Everyone has their own degree to which they want to ensure they won't have future problems. If having a mis-shift or a chain skip on a future ride is going to really bum you out and make you cuss every one that ever worked at the chainwheels maker, then set up a schedule to replace rings and cassette. If you replace one or the other, then replace the chain too.

I usually don't mind about problems that arise on a daily ride. I just fix after it's a problem.

This is a good thread, as I've wondered when my chain ring needs replacing too. I always thought the chain ring was worn when the teeth were fine points. Kind of like shark teeth.

Your "granny gear" is worn, but as noted above, it should be fine with a new chain, it's not too bad yet. The other two look better.

And second the admonition to clean the drivetrain more often. Regular cleanings could easily double your drivetrain life (chain/cassette, rings don't wear as fast). Also, google the chain measurement method referenced above. Replace your chain before it is way whacked out, it'll save a lot of headaches.

the others who are working mechanics can explain better than me, but before you get to the "shark teeth" point, the space or dip between each tooth gets worn deeper and wider, so when you put a new chain on, this accelerates chain wear----now how much and how fast this happens, I dont think photos on the web of a chainring can show this.
I know that when a new chain is put on a bike, and you do that "pull chain away from chainring" test to see how much space shows, an experienced mechanic can eyeball it, but I dont have the expertise on this, and anyway, this is internet diagnostic, so only can do so much.

all I can say is that when a cassette is worn enough that skipping can happen with a brand new chain, my experience shows that the cassette can still look fine at a glance, ie no specific shark tooth going on

so we come back to being aware of monitoring chain wear, I use the "1/16 rule over a foot" thing, as my point of reference to change a chain. An old bike of mine went to a good 2/16ths after years of commuting and ignoring measuring, so needed a new cassette at that point.

or you do like friends of mine do, ignore chains, clean grindy paste off once a year to feel better, and dismiss the "change chain at 1/16th" rule as not needed, and ride their bikes on same chains forever, cuz they wear together and "dont skip", so they are content. (until they one day gripe because a bike store tells them they need a new chain, new cassette etc, but hey, you can lead a horse to water, but........)

😅 I've rarely used it. That's just the design. I think it's so old school they don't care to redesign it to "shift" better

granny gears are pretty basic, from my experience.
I had a 28t I took off a 7n spd bike in about 1990 to replace with a 24t, and stuck the 28 in a box where it sat for decades until my wife had a 9 spd bike with too high gearing. I changed her cassette to the largest I figured her rd could handle, and changed out the 30t granny with the old 28t, which had the same bolt pattern, and it shifted perfectly. The old 28 didnt have any ramps or pins, but as a granny, it worked fine.
I have also changed 30t granny gears on 9 spd bikes to flat, ordinary 26t chainrings, and even with sti shifters, they just plain work, shift fine and have no issues at all shifting wise with no fd futzing around at all.

ps, looking again at your copious amount of photos, your rings look fine.

Middle one looks kinda tired.

It seems to shift ok. But my thinking is, like the cassette, if you wait till the shifting is bad, then that means probably your cassette is probably worn out. So I'm thinking let me see if this is worn to the point where it may accelerate a good chain to bad.