Small to small big to big

[GrumpyGregry]

Yebbut, personally I'm not aiming at the limits of human performance. I'm an old git bumbling about on a bike blissfully unconcerned about my chain line and it's terrible, shocking inelegance.

In the catalogue of my terrible shocking inelegance on a bike the chainline is the least of my worries.

 

[GrumpyGregry]

And the cassettes got wider and wider and cross chaining angles got greater and greater. On a 5 speed block the angle 'fully cross chained' was only 1.8 degrees.
And what about the wear? So little attention to the wear. It's not all about efficiency, you know, it fact that's the side benefit to sensible avoidance of cross chaining.

Did you get the lottery numbers right btw?

Yes, wear may be an issue. Is it a significant issue? Especially with modern chains designed to be laterally flexible?

 

[BikeCurious]

Can someone explain why big-big is so much worse than big-small? The big chainring is lined up with the middle of the cassette so the maximum deflection in either direction is the same. If we should avoid the two biggest sprockets when we're in the big ring because the chain angle is too extreme then following the same logic we need to avoid the two smallest sprockets! Why then do they even make 10/11 speed cassettes when we can only use the middle 6?!

 

[ufkacbln]

Can someone explain why big-big is so much worse than big-small? The big chainring is lined up with the middle of the cassette so the maximum deflection in either direction is the same. If we should avoid the two biggest sprockets when we're in the big ring because the chain angle is too extreme then following the same logic we need to avoid the two smallest sprockets! Why then do they even make 10/11 speed cassettes when we can only use the middle 6?!

Tension?

The Big - Big requires a greater chain length than Big-Small

This is taken care of by the deralieur arm, but the chain is still at the maximum tension

 

[Tanis8472]

I thought the centre of the big and small was aligned with centre of the rear

 

[Tim Hall]

Tension?

The Big - Big requires a greater chain length than Big-Small

This is taken care of by the deralieur arm, but the chain is still at the maximum tension

Surely the tension on the chain due to a well nourished cyclist giving it "some welly" trumps the tension due to various sprocket/chain ring combinations.

 

[Apollonius]

So, what breaks chains then?

 

[Smokin Joe]

So, what breaks chains then?

Faulty chains.

 

[ufkacbln]

Surely the tension on the chain due to a well nourished cyclist giving it "some welly" trumps the tension due to various sprocket/chain ring combinations.

The system is under different stresses according to where the chain is on the cogs

The same input will put different stresses on the chain in different gears

 

[GrumpyGregry]

So, what breaks chains then?

Cracks in the side plates, usually, or burrs catching on mechs perhaps.

Running bib-big doesn't break chains*.

Nor does it kill kittens.

*see my earlier 'forever' post above.

 

[Ajax Bay]

Back from a good ride in glorious weather.

the catalogue of my terrible shocking inelegance on a bike

Do tell us what is higher in the @GrumpyGregry (in)elegance on a bike stakes that might shock the sensitive.
I'm not suggesting cross chaining breaks chains btw, just wears them unnecessarily and reduces their efficiency: the latter I think you have agreed.
You 'lottery numbers' banality was not addressed to me, btw, which is just as well as I have never played the lottery (that's what clogs up the shop queues on Saturday and Wednesday evenings, parting people from their money for 'noble' causes)?