mschwett 

conclusion, for anyone who cares .... cassette was the culprit. continued to skip (although slightly less) on the 11t and wiggled a bit on the next couple small cogs, so i replaced the cassette. totally perfect now, with no other adjustments. bummed at the short lifespan but perhaps my own fault for running the original chain for 3,000 miles. going to replace the current chain sooner, and measure better, i guess.

may also try and obtain some of those small cogs so the next one isn't a complete replacement, but for now i'm enjoying that new drivetrain feel.

sean.hwy

I have a 14 inch metal ruler I bought on amazon that I use to check my chains. It was kind of pain when most ruler only went to 12 inches but you to to measure just little bit past that.

I have the park tool one also but I don't trust it as much.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

djb

I certainly don't have 12 spd lifespan experience, but the main thing to consider taking from this experience is keeping your drivetrain clean and lubricated.
Over the decades, I've generally gotten 5, 6000 kms (3, 4k miles) out of 7,8,9,10 systems (a bit longer with 7 spd perhaps) before my manual measurement gets to 12 1/16 wear point, and frequently get 3 chain changes on a cassette---BUT I also have always been a "wipe excess off chain, pulleys, with a rag, wipe down chainrings and "rag floss" my cassette regularly" sort of rider.
Having old rags around to do this very quick regular clean simply extends the lifespan of drivetrains--reduce the gritty pasty toothpaste off the contacting points and less wear is going to happen.

your drivetrain looks pretty clean, but how often you lube your chain etc etc is unknown.
So many of my friends are just terrible with drivetrain maintenance, just don't think of it and gloop sticky chain lube onto filthy cruddy chains once in a blue moon and then ignore it for another blue moon or two....

Am I correct in thinking that 12 spd chain lifespan is a good deal less than lower speeds?
Again, I only have real life experience up to 10 spd, and I've found 10 to be pretty similar to my 9 spd expectations.

mschwett 

i was using a very nice 18” ruler, and was not measuring any appreciable elongation! certainly not 1/16” in a foot. that’s why i hadn’t changed the chain… a bit of a mystery.

mschwett 

i thought i was pretty good with it. my routine was to spray degrease, rinse, and then use the park tool cyclone thingie every two weeks or so. a quick wipe and muc-off dry lube every week or so. in retrospect that may not have been a good routine for +/- 125 miles a week in sometimes foggy and sandy conditions. a few of my routes often feature some blowing sand across the road, and of course fog is a regular feature here. maybe harder on the drivetrain than the mild temperatures make it seem?

djb

we all have our opinions on chain maintenance, so no lack of opinions on that!
I personally don't do the degreasing thing, as I reckon it takes the (hopefully) clean lube out from the innards where it is doing its thing nicely, and you have to get new lube back in there. I have numerous bikes and family bikes, so just don't want to spend the extra time degreasing, but am pretty regular with wiping etc

BUT as you say, riding conditions, rain, gritty roads, sand, whatever, all are factors. I ride less in gritty, in rain a certain amount but thats on my old commuter usually 7 spd, so more foregiving, plus anyway I always do chain wipedowns post rain rides anyway and often relubing...........like I said, no end to maintenance opinions.........

I can say that from what you said about your 11t cog riding time--fairly similar to mine frankly, ie not often, thats odd as I have had skipping on worn cassettes with new chains on the most commonly used cogs, which makes sense doesnt it, they are worn more.

as per measuring, and you not noticing stretch, that does touch on the one human eye fail factor possibility, how you keep measuring device in place and eyeballing it perfectly to really get a good measurement--lots of possible mistakes, your hand moves etc etc

Id still put a new 11t cog on that cassette to see how it goes, could be worth trying, just not to throw away a useable cassette, but thats up to you. I'd be tempted, but more experienced mechanics here probably have a better opinion on this than me.
Is weird those scratch marks on cassette lock ring
also, lock ring could have been loose a bit? I've had this happen? who knows, internet guessing BS on my part ......

mschwett 

LBS said they can't get them. velofactory wouldn't ship to US, but a couple of the UK sources didn't object when i put in a US address and paid for international shipping. let's see if they come through. got three 11t and two 12t, even with the $$ shipping it would save a lot of $$$ cassettes down the road.

jaxgtr

For one off small parts and cogs, I have used this place. Generally have what you need

https://www.bikeparts.com/categories...B%5D=1230&pN=1

mschwett 

nice! unfortunately no shimano 12 speed cogs. seems like for some reason shimano doesn't want people in north america to have loose cogs