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1/8 chains or 3.32?


Perez

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I just made this post to have some opinions, i run a Bonz freewheel 108 and a rear Echo SL hub with Echo sproket, 18x15.

Recently i used a Odyssey Bluebird Chain, and it last me 4 months until it reach maximum stretch for the snails/frame.

I just bought a Kmc 810 1/8 Chain, never used this one and this size, any opinions?

Im a heavy guy, 90kg, but smooth :wink2: never broked a chain for the last 15 years of riding, change them after 4/5 months for precaution, but a had a nasty crash last year, and i lose confidence on the drivetrain..hell!

The crash was because my rear hub stripped on a gap, not a broken chain by the way.

Thanks guys!

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1/8" is more resistant due to the width.

I don't really follow that. if you compare a 1/8" and 3/32" chain the only difference is the pin length and roller width. The plates are the same thickness and so there's basically bugger all in it, except that the 1/8" chain will be heavier (and potentially very slightly weaker...

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the narrower a chain the more bending tension is on the pin.

try to pull a metal rod of i.e. 2mm that is fixed at both ends to bend it in the middle,you´ll do it with one finger.

try it near the fixation points and you´ll not bend it,even when its longer.i know that sounds wrong but...

in theory its basically as you said,but in real life it happens to be this way :wink2:

Edited by FamilyBiker
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the narrower a chain the more bending tension is on the pin.

can you follow this?

No, because the bending force is resisted by the plate right next to it, so it becomes a shearing force.

Edit: Oh I think I see what you mean now... but how often do you see a pin snapped in half? It's a consideration in theory, but not in practice. In fact, in theory, surely the longer pins would be weaker, as the length of the lever is longer (the force being applied in the centre of the pin by the sprocket)?

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the narrower a chain the more bending tension is on the pin.

try to pull a metal rod of i.e. 2mm that is fixed at both ends to bend it in the middle,you´ll do it with one finger.

try it near the fixation points and you´ll not bend it,even when its longer.i know that sounds wrong but...

in theory its basically as you said,but in real life it happens to be this way :wink2:

not sure if what your saying is getting lost in translation but it makes no sense, are you saying narrower chain pins are weaker?

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In fact, in theory, surely the longer pins would be weaker, as the length of the lever is longer (the force being applied in the centre of the pin by the sprocket)?

That's how I see it.

its more force per mm2,because the contact surface is smaller,the smaller the surface,the higher the force(pure math physics) the more bending and fatigue happens.

hence yes,i am saying it.

You've lost me... Contact surface between what and what? For a given 3/32" sprocket/freewheel the chain sees the same contact area but a wider chain (with similar diameter pins) will experience higher bending moment at the point where the sprocket/freewheel touches due to the larger moment arm...

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That's how I see it.

You've lost me... Contact surface between what and what? For a given 3/32" sprocket/freewheel the chain sees the same contact area but a wider chain (with similar diameter pins) will experience higher bending moment at the point where the sprocket/freewheel touches due to the larger moment arm...

contact between the chain rolls and the pin....the rolls go round the pins you know...

and afaik the force is applied to the rolls at least

Edited by FamilyBiker
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The force being applied to the chain is the same but for the wider chain (with wider rollers) that force is spread over a very slightly larger area.

Not that I disagree, but I don´t understand how? I fully understand rollers are wider, but without them "wrapping" around teeth the contact surface is determined by smaller part of equation i.e. teeth in this case, or?

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blue-rollers´n´plates

green-pin

yellow-contact surface

orange-initial force

red-resulting force

post-30389-0-75608900-1358453683_thumb.p

the red forces in the drawing are compensated in a big part by the fact the chain has no end when joined together,but minimal bending forces will stay present,i think especially with the peak forces trials provokes.

if you make the transfer surface smaller,changing the leverage between the initial lever(roller contact point on pin) and the resulting one(the plates wich dont change size),creating a different force transmission, the remaining parts will be put under the force that isnt relieved in the first part,making the whole system weaker.

hope it makes sense

Edited by FamilyBiker
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