Is this chain ring knackered?

[the stupid one]

Me again. I chose this username well.

Today, for fun, I decided to take apart the cranks and bottom bracket on the mongrel bike. Plan was to follow a YouTube video, clean everything up, replace the bearings, and get it all back together.

Turns out the crank arms aren't keen to be going anywhere. They've been left overnight in the warm embrace of penetrating oil, and if they don't want to move tomorrow then I'm calling it off, except that while I was up-close and personal I noticed these cracks and deformities in the middle chain ring . . .

Excuse the dust. It seems that there are two pairs of these, opposite each other, and with four teeth between each split, and there's what looks like a drilled hole at each split, suggesting the split is deliberate and the hole is there to prevent it continuing.

So is it a feature to perhaps aid the movement of the chain on/off the ring, or do I need to replace the entire works?

I had the bloody thing on the garage floor this afternoon while I wrestled with the cranks - crank-puller, heat gun, mallet, the works. There's a good thread somewhere here that I pored over whenever I was getting my breath and temper back. Fun. I did it for fun.

Thanks,

Steve

 

[froze]

The teeth on those rings are badly worn, yes you need to replace them. And while you're at it you might as well replace the cassette and the chain.

 

[Yellow Saddle]

Using toilet paper as a filter doesn't do anything for the photo. Try one with better light and a better angle and brush the crappola off first. I can't figure out what's going on with those teeth. However, the chainring is NOT worn at all. The teeth don't show any wear whatsoever.

 

[Rickshaw Phil]

These cheap pressed steel chainsets often have those little deformed bits which, as you've guessed, are there there to aid shifting.

It seems to have signs of wear and this type doesn't last long anyway so use until it's completely worn out or you're fed up with it, then replace with something better.

 

[Jody]

Not sure how you would loose chunks out of a middle chainring like that. Time for a new one.

 

[Tynan]

is it the centre ring of three? which one do you usually use?

I'd be inclined to keep an eye on it and carry on

 

[the stupid one]

Well, thank you all for the speedy and conflicting responses! A good read, entertaining as well as informative.

Yellow Saddle, I apologise for the quality of the image, I was trying to clarify the applicable bits. I thought my Photoshop work was pretty good there, I suspect I will find you hard to please.

I haven't been able to face the bike yet today, but if the cranks are still seized I think I will leave it for now. I have a chain-wear gauge on the way so I'll have more info soon about the state of the entire drivetrain, and I'm hoping to upgrade/renew the parts bit-by-bit as I can afford them. There was a bit of a noise from that region (in time with pedalling) on the fifty miler on Monday, but nothing particularly loud or grinding. I usually stay on the larger ring, with occasional excursions to the funny-looking middle and very rare moments on the inner. For this month I think I may just replace the pedals.

S.