Why are my cassettes only lasting as long as the chains?

[MossCommuter]

Ah guess it's nothing like that I average 80 on hilly rides in the Peaks (and I'm a out of the saddle climber - so big gear) but on the flat, average is about 90, even with a 53 chain ring. 80-100 rpm is the most efficient !

Worth learning to spin more !

Never measured it but I did build a spreadsheet to work it out from the gear ratio and measured speed.

I reckon my cadence is about 60

 

[GrumpyGregry]

If you are using mainly 7 or 8 out of 8 you aren't giving your cassette a fighting chance. The smaller sprockets will be doing nearly twice the work of the largest ones.

Big ring up front and a larger choice of sprocket at the back might see you getting better vfm.

Couple of times a week I force myself to spin to and from work by sticking it in a lower gear and leaving it there. Over time it makes a big difference to your cadence.

 

[Moodyman]

I'm big and have a hilly commute - both of these wear the drivetrain faster.

But, I still get two chains per cassette. As others said, spin.

 

[MacB]

Yes

ditch the big ring and put a bigger middle ring on

 

[MossCommuter]

So, is the degree of wear to the chain no indication of the wear to the cassette? I had believed it was.

 

[GrumpyGregry]

So, is the degree of wear to the chain no indication of the wear to the cassette? I had believed it was.

It is an indication tis all. .75 and you should get away without a cassette swap. But no guarantee, esp. if one or two small sprockets have been used excessively.

 

[mcshroom]

A badly worn chain will wear out a cassette faster, but even a brand new one will cause some wear. I've got a 3x8 speed bike, and in general I find that for a certain gear in the middle ring (eg: 2-7) then you get an almost identical gear in the bigger ring by dropping a couple cogs at the back (ie: 3-5). It's also more comfortable to push against IMHO.

YMMV of course. To see how many duplicate gears you have try plugging the numbers into a gear inch calculator like this one

 

[MacB]

So, is the degree of wear to the chain no indication of the wear to the cassette? I had believed it was.

it is but the wear isn't even, generally I assume that the more teeth engaged the less wear and vice versa. I think it's a combination of amount of teeth and force going through them. For example:-

32x12 is the same gear as 48x18 but the latter has far more teeth to spread the load over

If you're commuting on a 3x8 but only really using the middle ring then just treat it as a 1x8 and gear accordingly. As in trying to make the middle of the cassette your regular use gears and the extremities seldom used.

 

[MossCommuter]

It is an indication tis all. .75 and you should get away without a cassette swap. But no guarantee, esp. if one or two small sprockets have been used excessively.

I need to swap the cassette at 0.5%. I think I should have ignored the wear while the chain/cassette were functioning together.

If you're commuting on a 3x8 but only really using the middle ring then just treat it as a 1x8 and gear accordingly.

As a repair, while I consider getting the gearing all sorted, can I buy just the small ring? It's separate from the rest of the cassette

 

[fossyant]

So, is the degree of wear to the chain no indication of the wear to the cassette? I had believed it was.

Not if using just two or three sprockets mainly. And smaller sprockets wear more (more rotation and more friction due to increased 'bend').

60 rpm is way too low, it's also putting knees under stress. I'd expect 60 grinding out of the saddle on a steep hill.

 

[fossyant]

As a repair, while I consider getting the gearing all sorted, can I buy just the small ring? It's separate from the rest of the cassette

The locking sprocket - what size is it - hyperglide I assume ? Ebay possibly. (I may have spares though )

 

[mcshroom]

Ask on here, I'm sure someone will have an old cassette where they didn't wear out the little cog.

 

[MossCommuter]

The locking sprocket - what size is it - hyperglide I assume ? Ebay possibly. (I may have spares though )

I don't know what a "locking sprocket" is , but this sprocket has 11 teeth and is separate from the other 7 on the cassette, the cassette is a Shimano one, with a lock-ring on the outside of it. When I search Fleabay all I find are complete cassettes (and jockey wheels).

 

[fossyant]

It's the last sprocket with the knurled edge. Ah, don't have any 11 sprockets, only 13's on Hyperglide.

 

[MossCommuter]

It's the last sprocket with the knurled edge. Ah, don't have any 11 sprockets, only 13's on Hyperglide.

Thank you (I'd never noticed a knurled edge).

My 2nd smallest gear has 13 teeth on