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Two new chains wear slower than one?
#11
Treehugger Wrote:
sirromj Wrote:When swapping at 0.75%, how many chains until the cassette and chainrings are too worn to accept a new chain?
Tinc said his cassette is about 3 years old.
Apples and oranges.
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#12
Laggingbehind Wrote:So you doing nearly 900 miles in just over a month and you're worried that your chain and rings have worn out after 14 months.....seriously

Just looking to optimize.
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#13
Yeah stupid me, imagine, wanting to extend the life of the components I spend my hard-earned money on. What a fool. Duh.
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#14
sirromj Wrote:Yeah stupid me, imagine, wanting to extend the life of the components I spend my hard-earned money on. What a fool. Duh.


Fool :lol: :lol:
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#15
Actually I think you're giving me too much credit...

... it was nearly 900 miles in just under two months... not one month. Big Grin
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#16
Apples & oranges based on......??

Two chains will perceive as wearing slower as you're splitting the wear, but it could actually increase the chain ring wear rate if you're not spot on with swapping at regular mileage intervals as the two chains may be stretched by different amounts.
Chain rotation is usually employed to ensure maintenance is correct whilst keeping the bike working.

Chains wear - fact. By how much & how quick depends on loads of things, so we'll just accept it happens.
(It's not actually "stretch" as such, but lets not go there :roll: )
Chainring & cassette wear is caused as the chain meshes with the teeth. With a unstretched chain this contact is tiny & made by the chain rollers, which spin - therefore wear is minimal if even present.
The teeth pitch is matched to the link pitch & once stretched the chain rollers are on a different pitch to the teeth, contact is greater & longer, the roller often can't roll & slides onto the tooth, so the tooth is worn to the same pitch as the chain.
The chain continually stretches & the tooth wear is exponentially accelerated.

You should consider the chain as disposable. Buy many, buy cheap - that way you don't get upset throwing them away.
To maintain cassettes & chainrings throw the chain away as soon as it hits 0.75% wear.
That way, theoretically at least, the cassette & chainrings will never wear to the point of replacement.
(In the real world with rain, muck etc.. you'll get through them eventually.)

Larger rings & larger gears are you friend as that reduces the force on each tooth/link.

All bicycle chains are 1/2" pitch, so over 12 rivets will be 6" or 152.4mm. At 0.75% wear the same measurement will be 153.5mm..... yep 1.14mm!
Do the same thing over 12 links (24 rivets) & you're looking for nearly 2.5mm.
You can measure it or you can pay £5 for a simple gauge...You can find them much cheaper though. I paid £1 for mine in a sale bin Big Grin.
I also use the first method here when my gauge isn't to hand.

Other tricks include steel cassettes & chainrings, gearing selection, pedaling in circles rather than stomping on the power stroke etc.. etc..
But chain maintenance will make the biggest difference.

I run a road cassette (12/27) on both my HT & FS without issue. Currently at least 3 years on Ultegra cassettes. I have alloy chainrings on everything, at least 4 years old & appear unworn.
My roadbike is now 10 years old (I think) has done thousands of miles, the braking surfaces wore out & I changed the wheels, but currently still on the original cassette, chainrings & chain Confusedhock: Honestly Big Grin
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#17
Well explained Tinc

On a related note, has anyone seen any decent chain deals online recently?
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#18
Siromj, i dare you to argue against that lol Wink

Nick, i usually find CRC are cheapest for chains, but the OnOne site often has some good deals too. My chain is almost at .75% already, i've finally got a chain wear guage!
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#19
Thanks Tinc for the explanation, very helpful. I'm not going to argue against that, am convinced enough to give it a go, despite two chains and a chain wear measurement tool arriving Friday. The chain in question here is way past fitting on the 1% wear tool, the gap between the inner and outer link along the pin looks around 1mm.

The chain wear on my other bike is at least 1%, is this amount of wear likely to be too much for a new chain to mesh properly? I guess I could try a new chain, but I'm guessing it would probably not work well and would be better off just running into the ground?

Cheers.
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#20
1% *should* be good for new chain on existing cassette, the reccomended wear interval is between .75 and 1%. I'm gonna change mine on .75, which prob won't be too long now.
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