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Re: Reverse-wearing a cassette...?

Posted: 16 May 2019, 8:16am
by Jamesh
Just a couple of novice questions

If I do two 20 mile rides during the week and a 30 miles on the weekend (70mpw / 3500mpy) how often do I need to change the chain?
Is once a year enough if I swap from winter summer bikes at Easter?

How many chain lives would you expect to get out of a cassette.

Finally I had a chain snap on me last night first time ever. Think I had used a quick link on 10 spd chain. Do people recommend them.? Also I put the chain back together wrong way around the rear mech tab so had to break it again and rejoin. Will that link I have broken twice be a weakness and how can I make good as it's a new chain?

Cheers James

Re: Reverse-wearing a cassette...?

Posted: 16 May 2019, 9:15am
by Brucey
different riders, different conditions, and different chains wear differently. If you want to change the chain and cassette together then 3500 miles is about right for many people. If you want to change the chain only and keep the cassette then I would suggest two or three chains a year might be about right. The latter strategy preserves the chainrings as well as possible too.

Re 10s chain, if several of the original links have failed then I would condemn the whole chain regardless of age. Quicklinks come in re-usable and non-reusable flavours; it isn't clear whether non-reusable types are likely to be damaged (thus increasing their subsequent chance of failure) by being remade a number of times or if the links simply wear so that they come apart more easily than they should do.

In any event if a > 9s chain is joined using a chain tool or the QL is assembled incorrectly then anything can happen.

cheers

Re: Reverse-wearing a cassette...?

Posted: 16 May 2019, 9:29pm
by Jamesh
Thanks Brucey

Is there a tool that is better than a chain splitter?

Think I'm good to use the chain for a season as I use a winter bike and a retro bike when I feel inclined.

Cheers James

Re: Reverse-wearing a cassette...?

Posted: 16 May 2019, 10:41pm
by Brucey
to split a chain (where no QL is fitted) a chain tool is the only sensible thing. There are many forms of chain tool but they all do about the same job when it comes to splitting.

To join a chain you can

a) use a quicklink
b) use a special joining pin (some chains only)
c) use a chain tool.

c) is just not recommended for >9s chain. In point of fact a joined link (using an original chain pin just pushed back in) in any chain with peened/swaged (slightly mushroom-headed) rivets isn't quite as strong as the rest of the links. This includes nearly all derailleur chains (including all that are currently sold as 7/8s ones) and some 1/8" chains too. The pin loses its swaging on the way out and it damages the side plate too. [You can demonstrate this to yourself if you have a few spare links of new chain; break and remake a link, then go to break it again. You will be surprised (and disturbed) how easily the pin comes out of the joined link a second time. You may also see bits of swarf appearing first time around. Nonetheless it is the way many chains are joined in bike factories simply because it is cheap and quick...]

All 10s, 11s etc chains use so-called 'bullseye riveting' which is fantastic but it means the rivet head overlaps the hole in the sideplate more than normal and it increases the load required to push a pin out of the chain. It diminishes your chances of making a really good joint by pushing one of the original pins back into the chain to about zero; an emergency get-you home only.

Some 9s chains are built like 7/8s chains and some are built more like 10s chains i.e. with bullseye riveting.

Some chains use a special joining pin. These pins cost a small fortune and can only be used once; if you want to take the chain off the bike you need to split it (somewhere else, not the same place) and rejoin it again using another special pin. These pins are designed to be a tight fit in the (now-damaged) side plates and aren't swaged/peened. This means that this pin can't be as strong as the others in the chain. Thus in some narrow chains (eg campagnolo 11s) it isn't adequate that the special pin is simply a tight fit, it needs to be swaged like all the other pins in the chain, for which you need to use a special chain tool which allows you to peen the head of the 'special pin' once it is installed in the chain.

Use of quicklinks completely sidesteps all 'special pin' issues. Third parties (eg KMC) make various different QLs that are compatible with pretty much any other chains you can buy. The QL is most likely not quite as strong as the other (undisturbed) links in the chain but it is probably (-with the possible exception of special pins that are peened after installation- ) still the strongest way of rejoining a modern chain.

BTW even with a so-called 'reusable' QL (which you can use to remove a chain for cleaning for example) you should buy a new one to use with a new chain; the pins in that link wear just like any other and only a new QL will match the rest of a new chain.

cheers

Re: Reverse-wearing a cassette...?

Posted: 17 May 2019, 7:16am
by Jamesh
Thanks Brucey
that's so helpful.
Does anyone make a tool to peen chain pins over?

Think that I need to get some quick links tbh.

Cheers James

Re: Reverse-wearing a cassette...?

Posted: 17 May 2019, 8:43am
by recumbentpanda
It interests me that some velomobile riders report much longer drivetrain life than average[*] With modern materials and manufacturing methods, surely it’s possible to design a derailleur compatible chaincase for some types of bike?

[*]velomobile designs differ in the amount of protection they give to drivetrain components.

Re: Reverse-wearing a cassette...?

Posted: 17 May 2019, 9:11am
by Brucey
Jamesh wrote:Thanks Brucey
that's so helpful.
Does anyone make a tool to peen chain pins over?


yes, several types are out there but NB the peening is

a) carried out on a special pin not a standard one from the chain and
b) the special pin is a different size from a standard one; remember that part of the problem is that the hole in the side plate is damaged (made oversize) by pushing the original pin out; once this happens standard pins don't fit correctly any more.

This is a campagnolo 11s joining pin
Image
if you look carefully you can see that the diameter of the pin where it fits to the side plates is fractionally larger than the main part of the shank; this is to allow for the damage to the side plates. You can also see the size of the flange on the end of the pin; something similar gets pushed through the side plates when the chain is split; no wonder they get damaged....

Think that I need to get some quick links tbh.

yes that is the best thing to do. Quite a lot of riders carry one as a spare whilst out on the road; with one you can make to good repair (rather than a shonky one) to a chain that breaks mid-ride.

cheers

Re: Reverse-wearing a cassette...?

Posted: 17 May 2019, 9:22pm
by The utility cyclist
Not quite related to the problem solving initially intimated but for a while now I've been running small/small a lot in areas where my speed is below 17mph so - mostly around town but also up slopes.
My commute/ute has a 26t inner and cassette is 12-28, the chain and cassette are quite old TBH I've lost count of how many winters but I think I mentioned it elsewhere), the chain is very stretched but with same cassette still keeps going.
My thinking was will I not only get more wear out of the cassette by deliberating cross chaining (though I don't do 26/12 that often but the 13/14/15 get lots more use, also wear the middle ring less which is the one i tend to use the most on both the daily and the audax/winter racer/tourer bike (which has a 24T inner)

I've no idea how effective it is but I'm fine with the high cadence if I'm near the higher speeds and there's no problem shifting both front and rear mech at the same time so I can shift up as and when I feel like it or terrain/legs dictate.

Re: Reverse-wearing a cassette...?

Posted: 17 May 2019, 9:39pm
by Brucey
recumbentpanda wrote:It interests me that some velomobile riders report much longer drivetrain life than average[*] With modern materials and manufacturing methods, surely it’s possible to design a derailleur compatible chaincase for some types of bike?

[*]velomobile designs differ in the amount of protection they give to drivetrain components.


I think that a lot of chains on recumbents last longer in good part simply because they are much longer, and consequently usually (but not always)see fewer loaded flexions per unit length of chain. That they are usually cleaner helps enormously too.

I also think there is (outside of racing) an argument to be had about chain tensions and chainring sizes.

cheers

Re: Reverse-wearing a cassette...?

Posted: 18 May 2019, 12:53am
by NickJP
I find that the synchronising chains on our tandems last several times as long as any of the other chains on bikes I ride. I guess there are three factors at play:

1. Perfect chainline all the time
2. The chain is never being bent to force it to move between chainrings or cogs
3. The chain is longer than a rear drive chain, so each link sees less wear because it passes over a cog/chainring fewer times per unit distance travelled

The last point is also probably part of the reason why chains on recumbents last longer, as they're also usually considerably longer than on a diamond frame bicycle.

Re: Reverse-wearing a cassette...?

Posted: 18 May 2019, 1:26am
by Brucey
timing chains are also only ever used on chainrings of a reasonable size; this not only lowers chordal losses but it means the chain links articulate through a much smaller angle, and thus would be expected to wear more slowly.

cheers

Re: Reverse-wearing a cassette...?

Posted: 18 May 2019, 6:21pm
by tykeboy2003
Brucey wrote:Reverse-wearing a cassette...?


From the title of your post I thought you might be talking about disassembling the cassette and turning the rings so that they rotate in the opposite direction. There might be some mileage in that, provided that such a modified cassette still facilitates reasonable gear changes.

Having thought about that, it wouldn't work because the tabs which locate in slots on the freehub wouldn't allow the rings to be fitted on the hub.

Re: Reverse-wearing a cassette...?

Posted: 18 May 2019, 6:55pm
by Brucey
with old UG sprockets you could turn them and run them in the other direction; this way every sprocket could have two lives. But not only does the HG spline prevent you from doing this, but the sprockets do too; the teeth are directional, and the ramps and gates in the sprockets are too.

cheers