Life expectancy on an EAI cog

Fixedweasel

I have EAI 16t cog and I was wondering what a reasonable mileage life expectancy might be? Or are there just far too many variables to give an estimate e.g chain line, tension etc, etc ?

I have done circa 4k miles on it and it’s looking a little tired, is it time to consign it to the bin ?

jbindman

i replaced my whole drivetrain in jan after 11K km on brixton cycles advice and im sure it was reasonable advice. id switched between the 17 and 18t at some point as well so the cog that got binned had maybe only done 8K anyway. it looked tired as in you could see the wear on the teeth, but the more obvious issue was chain rattle- and the chain was probably the third for that ring & cog.


its not the distacne per se its the wet and dirt-i clean mine but not obsessively. if you rode it all this wet year 4000 miles is probably enough.

Crumbling Nick

My current 18t cog has done about 12k miles. Third chain is due for replacement & I expect the sprocket will survive for the next one. I received advice here (a little while back, so not in the "archives") that 1 mm tooth wear is a reasonable limit in general engineering practice for chain drives similar to bikes. Last check showed about 0.5 mm, so I'm expecting quite a bit more life yet. Transmission rattles a bit when leg-braking, but that's been the case since the first new chain. I'm more troubled about the life of hub threads from frequent sprocket refitting than odd rattles like that. YMMV .

Bike is used in all weathers - it's my do-nearly-everything machine. Transmission is 3/32". Chain is only cleaned if I get fed up with the crud rubbing off on clothes, which is but once (and that was just a wipe with a paraffiny rag) on the current chain. AIUI cleaning is not beneficial to chain life, though I know of no science concerning cog & chainring wear.

jbindman

ah but you see nick some of us aren't crumbling and push the pedals a bit harder....

Crumbling Nick

And at my age, I'm never quite sure whether rattles come from the transmission or the engine :? ...

franklin pierce

Sprocket wear is governed by chain wear: the more worn a chain is the fewer teeth take up drive pressure and hence wear faster.

Four thousand miles doesn't sound like much though, I have some sprockets on tens of thousands which are only somewhat worn.

rustychisel

Yeah, 4000 or so sounds a bit light, but atrocious weather and a less than thorough cleaning regime plays a part. I'd expect to double this, or better...