My bike has a 3×8 system, a shimano hg41 cassete and a KMC chain, all installed in december when overhauling the worn transmission (and upgrading from a freewheel to a cassete). It has 3.200km on it at the moment. From my understanding, .75 stretch should be reached between 3.000 and 8.000km, and changed then.
I started noticing some chain slip a couple weeks back, at about 3k km, and, upon testing, noticed my chain was already stretched past 1.0. It has since gotten a lot worse and I am now replacing it with another KMC chain, and will see if i can save the cassete or if it won't play well with the new chain, in which case, i'll be replacing it with an hg31 since they're a lot cheaper right now, and the only difference is the rust resistance of the finish. I really hope it doesn't affect the crankset, since that'll be a far more expensive fix, but i believe it shouldn't have.
From now on i will check the stretch at least every 500km to guarantee i can also extend the life of the cassete. But besides being more attentive to premature wear… it's still premature wear! What might have happened, and what more can i do?
For lube, I use Algoo Premium wax based chain lube, riding in urban enviroments (so no dirt and sand, just soot).
At the start of the year, i used to wash the transmission (properly wash, soap and water with scrubbers) about once every 1-2 weeks, never lubing in between. That lead to 100-200kms between washing and lubing since it just took too long to do any more often, which was absolutely too long, especially when it rained, but even when it did not. The transmission was always perfectly clean, but i ran it underlubed or even downright dry on occasions.
About halfway through the transmission's life i changed to reapplying lube whenever it rained on my commute or i noticed any added resistance on the chain (usually after ~100km, which is a week), and just wiping off any accumulation of muck. That is pretty much what my fellow cyclist friends do (reapplying more often but without fully washing unless it's absolutely nasty), which is why i switched to doing it, and their chains supposedly last longer than mine did.
The transmission runs dirtier now, but, from my understanding, if that dirt isn't actual grains of sand and such, it oughtn't create the cutting paste effect, right? At least i think it isn't as bad as riding dry because i don't have the time to clean, and, plus, my lube is relatively clean to start with, it's not grease-like like some wet lubes are.
My theory is that, while i wasn't doing something terrible with either method, there's still something wrong with both of them. Maybe i should both clean more often – maybe monthly, or every 3 weeks, instead of every 2-3 months as i've began to do? Can't do it weekly/bi-monthly anymore, but i could do it more – while applying lube at least weekly, perhaps even twice a week if it doesn't lead to overlubing. In other words, cleaning more often but still with lubing in between, not one or the other.
Does that make sense? Would it explain the wear? Any other suggestions?
It shouldn't be which lube that's the problem, since it's a controlled variable (everyone i know here in my country uses them and, again, it supposedly lasts longer). Annexed are pictures of the transmission right now:
by Lorenzo_BR
1 Comment
A chain stretching out at around 3,000km is to be expected.