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[T4tomo]

Chains don't stretch, they wear. They are made of steel, not elastic.

The OP will probably find it was his nuts slipping moving the wheel marginally in the frame.

 

[silva]

Can't you just "measure" the wear by looking at the chain tensioner position?

 

[keithmac]

Can't you just "measure" the wear by looking at the chain tensioner position?

That's what youd do with a Motorcycle or single speed bicycle.

The chain stretch tools are for derailleur equipped bikes from what I can see.

 

[ColinJ]

Can't you just "measure" the wear by looking at the chain tensioner position?

It is surprising how quickly the wear happens. This picture shows a new chain and one that had only done a few hundred km!

 

[Juan Kog]

It is surprising how quickly the wear happens. This picture shows a new chain and one that had only done a few hundred km!

View attachment 620309

But you are the mighty and powerful @ColinJ , the trasher of bike transmissions. Us lesser mortals will get thousands of KM’s out of a chain …………….

 

[sasquath]

It is surprising how quickly the wear happens. This picture shows a new chain and one that had only done a few hundred km!

View attachment 620309

That's because chain on top picture is clearly overtensioned. Even 428 motorcycle chain would wear in no time when tensioned like a guitar string.

 

[ColinJ]

That's because chain on top picture is clearly overtensioned. Even 428 motorcycle chain would wear in no time when tensioned like a guitar string.

The chain actually wasn't quite as tight as it looks there. I've had a look back in my photos and found another one taken a few seconds later. You can see that there is actually a few mm of droop in the top run of chain...

The chain wasn't really being tensioned by the tensioner at all in the top picture. The chain was almost skipping over the jockey wheel because it was barely engaged. I had tried it with the tensioner raised but it WAS too tight then - the chain was noisy and didn't run smoothly.

Once the chain has lengthened slightly I don't take up all of the slack. I normally run it with about 8 mm of droop in the top of the chain.

 

[silva]

Well, maybe, due to the roller diameter being 5/16" for 1/8" single speed chains and 3/16" for 3/32" derailleur chains, the chain checker tool wouldn't be as accurate, maybe out by 2/16", but that's still good enough for me.

The roller diameters for single and derailleurs should be the same.
The 1/8" measurement refers the internal width, nearly the roller "thickness", not its diameter..

About the chain tension, any variation you could notice?

That pre-stressed, pre-tensioned, I've read that too here and there, afaik that can only be rubbish, except when the new parts would have been produced to give a smaller pitch, to then reach the standard pitch. If not, the new chain would immediately wear the sprockets to accomodate the longer pitch, voiding the very purpose of wear decrease.

 

[silva]

Btw, if you want least wear / cost, it's an idea to flip the chainring on its mount when you see sharkfin shaped teeth profile starts to form.
Because the hook form resists the disengaging of the links, aggravating the wear and accelerating the sharkfin shaping.
Same for rear cog.
Also for chainring: the teeth perpendicular to the crank arms wear more because peak force is applied in horizontal crank arm positions.
So rotate it 90 degrees on its mount, with 4-5 chainring bolts, 1.

I made flipping easier by replacing the silly small bolts (crap sleeved nut requiring special tool and care to not damage it), with standard outer hexagon headed M10 x required length bolts + nuts.
I put the bolt heads at the side of the chainrings ridges, they *just* have the required space avail, result is no key (17 mm) needed at that side, only one at the nut side.
Much easier to mount/unmount the ring, and also nearly impossible to damage bolts/nuts. And cheap.

 

[sasquath]

Also for chainring: the teeth perpendicular to the crank arms wear more because peak force is applied in horizontal crank arm positions.
So rotate it 90 degrees on its mount, with 4-5 chainring bolts, 1.

Last time I checked chain wraps around 180⁰ of the chainring -> wear is equal across all teeth.

 

[ColinJ]

Last time I checked chain wraps around 180⁰ of the chainring -> wear is equal across all teeth.

Only when the chain hasn't worn. Once the chain is slightly longer only a few teeth are fully engaging at any time and the force acting on the chain is not constant through a complete cycle of the cranks therefore some teeth have more force applied to them than others.

 

[T4tomo]

Yes, we use the term stretching, but we all know it really is the metal wearing. The metal between the rivets and the bushes wears first.

The RK415 is also pre-stretched, which might be helpful.
https://www.xlmoto.co.uk/mc-parts/c...s-415-630_c155/rk-415hsb-chain_pid-PM-4907102
Quote: "All 415H chains are pre-stressed and pre-stretched for superior performance and to minimise lengthening of the chain during its life."

how the fantastic mr. fox can a chain be pre-stretched. That is just utter marketing cobblers.

 

[silva]

Last time I checked chain wraps around 180⁰ of the chainring -> wear is equal across all teeth.

A cyclist doesn't put a constant torque alike a motor.
Two pedals, most force downwards, two force max, two force min, 4 quadrants, seen from the chainring: 2 cycles.

 

[silva]

You can split that quite easily, grind the rivets flush and use a dispensable screwdriver/ chisel to ping the plate off.

The Shimano Ebike chain may have been a better choice?.

Yes I know, but doing that is destroying the link, I need 106 links, the Regina 420's I found for sale at the best price were much longer so I plan to hammer one together with the unused remainders.