How far to push chain wear

[Vegan1]

First of all, @Vegan1

But much more slowly. Care to quantify that, to demonstrate why the wear on the chainrings should come into the equation? What is your experience? How long (how many 10,000km) did your chainring take to wear to a point where it needed replacement? Of course I appreciate you may not be able to answer this since I assume, as you have posted you "change the chain as and when it is needed".

Because at some point in time they'll need replacing if riding with a worn chain.

 

[Vegan1]

Nub:

View: https://www.youtube.com/watch?v=Wsb3PGzNlHM

 

[byegad]

Although an elongated chain will wear the chainrings a bit, they last far far longer and are not really part of this equation / balance, imo. This may be different on recumbents such as those ridden by @Tigerbiten and @byegad.
Starting from a new chain and cassette.
Option 1:
Replace chain before it gets to 0.75% and do so twice. Then change both simultaneously. 3 x £13 + £18 if the chain lasts 3000km: £57 for 9000km (0.63ppk).
Option 2: Run chain and cassette till skipping. Then change both simultaneously. £13 + £18; so if these together last 5000km (my experience) £31 for 5000km (0.62ppk). Appreciate these figures are based on a relatively cheap cassette so if you're running 11sp Ultegra, the figures will be larger, the sums different and likely the conclusions too.
Chain £13
Cassette £18

It seems you are advocating running 4 chains to 0.75% and changing the cassette at that point. In my experience on my commuter Thorn Club Tour bike, and recumbents is that changing one chain earlier gives better cassette and chainring life. Not far out, and as you say it all depends on how, and in what conditions, you ride, but over some 80,000+ commuter and recumbent miles I've found changing cassette at the end of the third chains life adds to the most used chainrings life.

 

[Ajax Bay]

It seems you are advocating running 4 chains to 0.75% and changing the cassette at that point.

Sorry - I can see that my post was poorly expressed (and so have edited), though the sums made it clear. From a new chain and cassette, two chain replacements before changing both. 3 chains per cassette.

 

[Ajax Bay]

change the chain as and when it is needed

Agreed - and when is that?

A worn chain will wear out not only the block but also the rings.

Agreed, but slowly
I asked: "Care to quantify that, to demonstrate why the wear on the chainrings should come into the equation? What is your experience? How long (how many 10,000km) did your chainring take to wear to a point where it needed replacement?"

Because at some point in time they'll need replacing if riding with a worn chain.

This is a qualitative rather than quantitative answer and doesn't really add much, if you don't mind me saying.
Agreed, but that point in time is likely to be a long way off.

Nub:

Not sure what pertinent point you think the video makes, other than if you use a really worn chain (how many thousand had that chain done? - 15,000 if true, extra-ordinary) then after 30,000km the chainrings will be a bit worn. But as he says "still using these cranks; still doing a good job". Exactly; and these are lightweight expensive ones (SRAM Red - £300 and chainrings at £85 (RRP). And he's run a seriously worn chain on them (which I am not advocating).
If you don't catch the 0.75% elongation, or don't wish to, the chain will eventually skip over a sprocket and tell you both it and the cassette need changing. The chainrings will suffer minimal wear. I guess if you are running expensive chainrings/cranks this is more of an issue than for 'normal' (non-weight weenie) riders.
An example chain ring is £15. Even if you get greater wear by wearing both chain and cassette together to 'the end' doing this 4 times (20,000km) and then changing both rings will only cost £30 or 0.15ppk. For normal level chainrings eg Tiagra, I suggest that they would last longer than 4 cycle with this regime so the actual ppk is commensurately less.

 

[Vegan1]

Do the figures when running ultegra and q rings.

 

[silvervanplumberman]

Run it till it snaps then new cassette and chain and repeat. Usually get around 6000 miles out of them like that as long as you keep them clean and lubed up. I run a winter and summer bike so looking at each one every other year. It works for me.

 

[Ajax Bay]

Do the figures when running ultegra and q rings.

Tell you what: you do the figures and add something useful to this thread. You can use my post as a template if that's easier for you.

 

[Vegan1]

Tell you what: you do the figures and add something useful to this thread. You can use my post as a template if that's easier for you.

Every 5000km you'll change the block and chain and every 20k you'll change the chainrings.

So at the 20k mark you've gone through 3 blocks, 3 chains and a chainset.

Ultegra block £48, Ultegra chain is £21 according to Wiggle, in the link it was a SRAM red chainset, replacement chainrings is roughly £130 for inner and outer.

(3*48)+(3*21)+130=£437 and this is before these are replaced again to go from 20k-25k.

£437/21=20 chains, 20000K/20 chains is a chain every 1000k if you are replacing chains only. Which means minimal (if any) wear on the block and chainset.

Not mention the potential pitfalls regarding shifting, power transfer etc from a worn block and chain.

 

[User6179]

Every 5000km you'll change the block and chain and every 20k you'll change the chainrings.

So at the 20k mark you've gone through 3 blocks, 3 chains and a chainset

4 blocks and 4 chains Shirley

 

[Vegan1]

4 blocks and 4 chains Shirley

Not quite, from 0-5000k would be what comes with the bike. Although you would need a fourth change at 20k which makes the numbers even more favourable to good chain maintenance and changing the chain in good time. I'm usually down the LBS at the 0.50 mark.

 

[slowmotion]

Last week, I was behind a young lady whose chain slipped when she was out of the saddle. She went over the bars, face first within a second. I'm not really interested in squeezing the last few miles out of my chain or cassette anymore. I really don't want an intimate facial date with a patch of tarmac.

 

[Ajax Bay]

a chain every 1000k if you are replacing chains only. Which means minimal (if any) wear on the block and chainset.

If I was replacing chains at that point I'd go for a bulk buy of chains.
Care to offer a view, @User9609 and/or @Yellow Saddle ?
Is there a relationship here between frequency (as in km ridden) and the relative cost of cassette and chain?

 

[Tigerbiten]

Although an elongated chain will wear the chainrings a bit, they last far far longer and are not really part of this equation / balance, imo. This may be different on recumbents such as those ridden by @Tigerbiten and @byegad.

Recumbents do alter the costs slightly.
In the last 4 years and roughly 32k miles/50k km I used ........
2x chainrings ~£44.
1x Rohloff sprocket ~£13.
12x chains @£12 each, £144.

I spend over twice the amount on chains that I do on chainrings and sprocket combined.

 

[Yellow Saddle]

Not mention the potential pitfalls regarding shifting, power transfer etc from a worn block and chain.

Why not mention them? What pitfalls are there and how is shifting and power transfer affected by a worn chain?