Singlespeed Chain Stretch Again

If it's one of the drop in (CC-2 and CC-3.2) tools they're really not hugely accurate. They measure wear/stretch and roller clearance.

I usually use them as a guide when i'm cleaning the bike, then use a 12" rule to check properly if the rubbish gauges say it's a bit worn, you'll probably find the chain isn't that bad at all.

Hey Mert. It is a drop-in one, yep. I couldn't find my decent metal rule earlier but the rule I did find showed it had stretched to a little bit past the 12" mark.

I've no idea why they're wearing so quickly!

Genuine KMC chain?

I believe so, yep. I got it from Wiggle I think.

A little bit past the 12" mark is pretty much how chains come out of the packet.

I wouldn't worry about it.

Did you measure it before you put it on to know if it had stretched for sure?

Also how much slacker does it seem now compared to 4 days ago?

@mert - I did check the chain straight after I'd fitted it and the checker wouldn't slot in, so there's definitely been some initial wear.

@zerocool - I checked the tension before my ride on Saturday and it's certainly slacker post-ride.

They do have a quick rate of initial wear IMHO. I put a little blob of paint on the drop out/hub nut once to check the wheel wasn't creeping forward, and it was rock solid but the chain slackened off anyway.

Doesn't really matter with singlespeed though, they'll be fine way past the point a derailleur chain is unusable. I've taken links out when the chain is stretched beyond the limits of adjustment on horizontal drop outs. Just keeps on truckin'

Thank @tthew - that's another question I had. Is there a wear point at which a singlespeed ring and cog become unusable with a new chain?

Its singlespeed just run it into the ground, replace it all when there are no teeth left on the sprockets

If you want to even out the wear then you can flip the sprocket / ring over and rotate the ring QTR turn to wear a fresh segment (if your cranks allow it). A worn sprocket still sort of works on a new chain but will make nasty noises under load so you'll know if it is ok or not.

Is it a proper kmc singlespeed/ hub gear chain?. I've got a narrow one on my work bike - it did stretch a bit but has very square / unchamfered side plates so is very tolerant of running slack without falling off.

Just to echo what others have said, I find it pretty normal to see a lot of initial "stretch" (or whatever may be happening for a chain checker to indicate stretch), and then it stabilises. I usually find I have to do a few retensions on a new chain then not touch it for ages.

Also bear in mind if you are putting a new chain on used chain rings and sprockets, there will be some initial bedding in and I imagine the chain is forced to stretch to adapt to the worn bits (at least that makes sense in my head!)

They wear a lot initially then settle down. If you have an even number of teeth on the rear you'll notice a bit of a 'rumble' for the first couple of rides when you put a new chain on mating wit the rear cog if it gets a bit worn but this'll calm down as the new chain wears. I change out chains if I get a failure in use or when I get to the point of running out of adjustment. They're so cheap it's not worth too much worrying about. I'm using kmc 9 speed at the mo as they were the only reasonably priced ones I could find at the time I needed some. They're ok though I don't like the heavy oil they put on them. Would get sram pc951 or pc971 for preference.

Is there a wear point at which a singlespeed ring and cog become unusable with a new chain?

Yeah, eventually, once they've got past the rumbly stage Del describes above. Thing is a new chain on old sprocket and ring wears REALLY quickly to mate with the old parts, so it's rapidly as worn as the one you just took off.

Definitely a false economy with singlespeed IMHO, just change it all at once. They'll sometimes last a few years, depending on use.

I have two rear wheels for my SS I've been running since 2017 with different cogs (+ and 29er options). I've changed neither cogs nor the thick/thin front I'm using. Ridden about 100k/week. Surly at rear and Shimano up front.

AFAIK the initial "wear" is mostly just the goo inside the chain moving around and allowing the chain to reach it's full length.

Really no point using a chain wear indicator on singlespeed, just run it into the ground, I ran my hub geared bike so long that the chain checker was too short to fit into the link!!! I only changed it as it got really noisy and couldn't hold any lube as there was so much space between the rivets and as spacer bits:)

The chains do settle a bit from new and need adjusting - I commuted on fixed gear for years. As for wear, if you've got 'evens' sprockets or chainrings (e.g a 16T or a 42T - not a 15T ot 43T) you can get the rollers wearing into the teeth if you've not removed a wheel for a while, and when he chain does go back on, it can sound like a tractor until you advance the chain one tooth.

Prime numbers FTW if you can (37:19 on 26" here) 🤓

Thanks for the advice everyone, lots of good stuff there and much appreciated. I'll guess I'll just retension and see how it goes. For those that run everything until it all wears together, at what point do you consider it done?

The ss kmc chain on my rohloff bike is now approaching 4000 miles. Ive adjusted it 3 times i think. Mainly road and mainly dry but some wet muddy days. Been putolined 3 times as well

It only takes a tiny bit of wear for the chain to look slacker. Dont overthink it

at what point do you consider it done?

Last time I lost one of the chain rollers into under the fridge. Had to remove the chain and it was so worn the ones that were being held captive only by the quick link made a bid for freedom. 😁

Ime KMC are notoriously crappy chains.

From being pretreated with too much sticky stuff from factory to rusting dry stored even.

They are cheap for a reason. Though one would argue not to spend too much on a chain as much of a muchness.

chain too tight? have you got enough defelction/slack when you first install it. If its too tight its going to increase friction and wear at the pins. there shouldnt be any tension on it at all.

Aha yes to what Olly pointed out as no.1 rule especially on motorcycles.