Cassette replacement after 1500 miles

[reohn2]

IME cheap shimano cassettes will just about last 2 chains if they have had decent cleaning regime and aren't being ridden hard over dusty environs.. however that can be shortened if the OP is a hard and strong pedaler, sometimes a lighter cyclist can get away with it if you can suffer the bedding in process.. except top gear.. with an 11 t bottom sprocket remember that when the chain is on these teeth maybe only 4 or 5T are getting a grip on all that torque you are mustering.. i find that the clubmen i help wear these out and many of the other mid range sprockets would last much longer. will

I find I consistently get three(Sram 971) chains @ 4 to 4,5k miles each to a Shimano cassette,though my cassettes are custom made 14-17-19-21-23-26-28-32.
I pedal a high cadence and ride 25% on forest roads and towpaths and I'm not light at 83kg.

[Brucey]

IME cheap shimano cassettes will just about last 2 chains if they have had decent cleaning regime and aren't being ridden hard over dusty environs.. however that can be shortened if the OP is a hard and strong pedaler, sometimes a lighter cyclist can get away with it if you can suffer the bedding in process.. except top gear.. with an 11 t bottom sprocket remember that when the chain is on these teeth maybe only 4 or 5T are getting a grip on all that torque you are mustering.. i find that the clubmen i help wear these out and many of the other mid range sprockets would last much longer. will

I agree if the top sprocket is used much then it tends to wear disproportionately fast. Like you say only a few teeth engage at one time and likewise there are only a few teeth to start with so they are bound to wear faster. But I think there is more going on than that.

First the top sprockets are usually made with an integral spacer. I think this makes it more difficult to make them in a hard material, so they are usually made softer than the other sprockets that are made from flat sheet.

Second the low number of teeth engaged means (for any given amount of hooking in the tooth shape) greatly increased chances that the chain will more easily skip (which feels like slipping but usually isn't, not really).

cheers

[willcee]

Brucey et al.. i agree, my take is that the quality of cheap shimano cassettes is today well watered down from several years back, i have examined several where one can see the trailing edge or chain contact part actually peened or flatted by the chain rollers.. that never used to be the case.. will