Chain rotating

IanMSpencer wrote:

I think the theory is probably to do with "end of life". A worn chain will not sit on a new cassette, and a worn cassette will skip on a new chain, but an old chain will sit on an old cassette. So by rotating chains you theoretically extend the time that cassette wear matches chain wear. I find that 3 chains to a cassette is a good ratio, and changing around the indicated lifespan as per spec. gives you a non-skip change. As I use the whole life of the chain, rotation doesn't help. I've not noticed the 3rd, most mismatched, chain last a shorter time than the first, so the premise of matching wear to reduce wear doesn't seem to offer significant gains. The trouble with rotating chains is the disconnecting and reconnecting. Unless you buy quick links specifically designed to be broken and reconnected (e.g. Wipperman), you should be replacing the quick link, so any wear savings are lost through replacing pins or quick links. Although most people do break and replace quick links like Shimano ones, you aren't supposed to.

When I was mucking around with wax treatments, I re-used KMC quick links and they seemed fine up to about 10 reuses.

I thought knc were reusable a few times and Shimano not.
I bought 2 kmc chains for £20 and then decided it can be a consumable item.

Hirsute wrote:

I thought knc were reusable a few times and Shimano not. I bought 2 kmc chains for £20 and then decided it can be a consumable item.

I bet the Shimano links are no different to the KMC ones, but carry a spare pair of links for if/when they get too worn whilst out on a ride. I like to carry spare links anyhow as you never know if you might want them and they don't weigh you down too much.

hawkinspeter wrote:

Hirsute wrote:

I thought knc were reusable a few times and Shimano not. I bought 2 kmc chains for £20 and then decided it can be a consumable item.

I bet the Shimano links are no different to the KMC ones, but carry a spare pair of links for if/when they get too worn whilst out on a ride. I like to carry spare links anyhow as you never know if you might want them and they don't weigh you down too much.

I had read that you can get away with reusing a shimano link, and have reused one a couple of times. I just took the chain off for a thorough clean and degrease and did replace the link yesterday, and I will say a new link is a lot tighter and harder to engage than a used one. I always bung the used ones in my top tube bag for emergencies though.

Adam Sutton wrote:

I had read that you can get away with reusing a shimano link, and have reused one a couple of times. I just took the chain off for a thorough clean and degrease and did replace the link yesterday, and I will say a new link is a lot tighter and harder to engage than a used one. I always bung the used ones in my top tube bag for emergencies though.

Good idea to re-use the links as spares. When I was re-using links, they did seem to get looser, so I guess the wear is at the joining holes and after too much use they don't hold together and can separate whilst riding (though that was after about 10 re-uses which is excessive).

Hirsute wrote:

I thought knc were reusable a few times and Shimano not.
I bought 2 kmc chains for £20 and then decided it can be a consumable item.

KMC make both, re-usable and the other sort. The reusable variety have an R in the product code, and "re-usable" on the packet!

In the photo, the dark one is reusable, the silver one is not.

IanMSpencer wrote:

I think the theory is probably to do with "end of life". A worn chain will not sit on a new cassette, and a worn cassette will skip on a new chain, but an old chain will sit on an old cassette. So by rotating chains you theoretically extend the time that cassette wear matches chain wear. I find that 3 chains to a cassette is a good ratio, and changing around the indicated lifespan as per spec. gives you a non-skip change. As I use the whole life of the chain, rotation doesn't help. I've not noticed the 3rd, most mismatched, chain last a shorter time than the first, so the premise of matching wear to reduce wear doesn't seem to offer significant gains. The trouble with rotating chains is the disconnecting and reconnecting. Unless you buy quick links specifically designed to be broken and reconnected (e.g. Wipperman), you should be replacing the quick link, so any wear savings are lost through replacing pins or quick links. Although most people do break and replace quick links like Shimano ones, you aren't supposed to.

If chains are cleaned and lubricated obsessively through truly-clean to carefully-lubricated (with effective lubrication designed for the purpose) then discarded as soon as the 0.5% "stretch" is detected, cassettes and chainrings will last much longer than the 3:1 ratio often quoted. The price for doing so is your time & effort.

It's a personal choice, mine being not just to avoid having to buy expensive new cassettes and chainrings but also to have an efficient and well-functioning transmission at all times. And to serve my minor OCD lust. 

Running worn chains on worn cogs may avoid the skipping that can otherwise occur with new-old combinations but the efficiency is likely to drop and the overall wear rates of everything will accelerate. Many don't seem to mind as they imagine they're "saving money". We have all been well-encouraged to apply only the accountant's rule to all matters though, eh?

If only there was a better set of uses for worn chains.  Perhaps a fad for chain jewelry could be induced? This would be far less costly to the buyers than, say, a Campag groupset jewelbox.

hawkinspeter wrote:

Following some detailed research, I've come to the conclusion that it's the sharp jagged bits on the cassette and chainring that cause the chain to wear. Since filing them down smooth, my chain lasts forever.

That's one theory; I find "using" is what causes the worst chain wear. I once left a spare bike in my mother's garage for four years, and when I returned to it the chain was in exactly the same state as it had been left. Not using is far and away the best way to prevent chain wear.

Rendel Harris wrote:

That's one theory; I find "using" is what causes the worst chain wear. I once left a spare bike in my mother's garage for four years, and when I returned to it the chain was in exactly the same state as it had been left. Not using is far and away the best way to prevent chain wear.

Make sure you store it in a climate controlled environment - look what happened to my chain

HoldingOn wrote:

ohhh - look at the design in that chainring!

Are chains not meant to look that lovely natural brown colour?

I usually give them a quick lick of hammerite to get them looking like that

Apparently Shimano recommends this as it can help maintain crank retention.

Also for cleaning just use the ShelBroCo method.

HoldingOn wrote:

(believe it or not - I have actually played around with my cadence, to see if a higher cadence wears out the chain quicker, as well as how it affects my speed)

What did you discover? I'd guess lower cadence was more wearing as it would impose greater torque on the chain than the same power at a higher cadence?

Kudos for dedication to research! I'd assume the average cadence isn't so important as the use in certain circumstances, e.g. people who don't change down at lights and so pull away in higher gears must stretch their chains more quickly even if their average cadence is much the same as someone who does use the gears more.

Chapeau for the research!

FWIW Sheldon Brown also has some thoughts on this subject.

HoldingOn wrote:

I'm sure someone has based a scientific paper around chain wear, if not there is a potential PhD for someone 

Not quite a PhD, but there was an engineering student buying used cassettes on EBay in 2018, who I corresponded with, as he wanted to know the maintenance regime the original owners had used. After detailed examination of wear to cassettes, he said his findings showed that big brand solvent-borne lubricants didn't do a good job at all, leading to direct metal-to-metal contact, and thus added wear. I seem to remember that he concluded that light machine oil was the best chain lubricant.  I've used sewing machine oil ever since!

Wipe down, wash with a weak solution of detergent in warm water, reapply sewing machine oil, wipe off again. I get about 2,500km out of a chain on the winter bike and 6,000km so far on the summer bike without discernable signs of wear yet.

HoldingOn wrote:

I tried one chain aiming for an average of 70rpm, then the next chain at 80rpm. Both indicated 0.5% wear around 1,000km (the 80rpm chain was a little earlier)

As well as having a wider gap between cadences (50 v 90?) I think you'd have to control for other factors such as applying consistent power input (and maybe ride the same gradients?) and ensure they were ridden in similar conditions. Also chainring and cassette sizes could be a factor, small-small causes more articulation than big-big so maybe faster wear?