Preloading roller chains

[Globalti]

It's a nonsense thread. Chains don't stretch, they wear, which has a cumulative effect over all the links. You can't pre-stretch or pre-load a chain, that's hogwash. Years of boiling motorcycle chains in hot wax tells me that a newly-greased chain might just "relax" a little after you've run it for a few minutes squeezing the lubricant out but you can't stretch it. The worst destroyer of a chain is bad gear technique where, by crossing the chain in extreme gear combinations, the rider forces it to change direction four times in each revolution, wearing it more than if it was running perfectly straight.

 

[Yellow Saddle]

It's a nonsense thread. Chains don't stretch, they wear, which has a cumulative effect over all the links. You can't pre-stretch or pre-load a chain, that's hogwash. Years of boiling motorcycle chains in hot wax tells me that a newly-greased chain might just "relax" a little after you've run it for a few minutes squeezing the lubricant out but you can't stretch it.

I'm afraid you can pre-load a chain and thus "stretch" it. It is a pretty standard concept in chain engineering. Have a look at @gbb 's explanation above. Add to that, the fact that the pins are not exactly perpendicular to the plates after manufacturing either. This all evens out very quickly and can be done via "stretching" or simply, use, as we do on bicycles.

I hate doing it but I do enclose "stretch" in quotations because, although a roller chain elongates slightly after preloading, none of the individual components get any longer. They simply settle. Aberations flatten, pins move inside the sideplate holes and change alignment. All of this causes a new chain to elongate after force and/or use. Only then does it arrive at its nominal pitch. It is actually below pitch when still in the box.

If you are a chain nutter like me, you'll appreciate the odd time when pre-load does raise its shy head. My last chain change caused chain skip in one gear. I was busy, didn't get around to buying and fitting a new cassette, and carried on ridinding. After 50kms, the chain had changed pitch and now no longer skip. This is a rare coincidence when jut-enough-wear meets just-too-short-chain but chain changes tune and voila, perfect match.

 

[Globalti]

Well you learn something new every day!

 

[gbb]

It's highly debatable In cycling terms if pre,loading would make any noticeable difference to chain life. In an Industrail or critical application with perhaps high loads, it may well make some difference and that's where OPs original article is focused on I suspect. You can't debunk it because it's a manufacturer describing a technique that extends chain life not shortens it so theres no gain for the manufacturer if the process is used.
I've tried loads of methods to extending chain in the past, nothing makes any discernable difference IME. I wouldn't bother deliberately trying to preload bike chain either, I still think of it as a consumable, clean it oil it and get on with life and dont worry about it

 

[silva]

It's still surprising that major industrial chain producers widely use this argument to sell to their industrial customers.
On the other hand, my nearest bicycle dealer, where I bought my older 2 singlespeeds, and later on converted these to fixed gear, being 15-20 years in this business, last summer claimed that roller chains link plates stretch and that this is the elongation, even after I explained the inner wear and added that I disassembled an old chain and could see how the pen holes became oval.

 

[ColinJ]

A new chain on my singlespeed bike fits almost perfectly without the chain tensioner applying tension, but after only a few hours of riding the chain becomes looser and needs the tensioner to do its job. I couldn't understand how it happened so quickly when the chain hadn't had time to wear significantly. A chain 'settling in' process would explain it.

 

[gbb]

It's still surprising that major industrial chain producers widely use this argument to sell to their industrial customers.
On the other hand, my nearest bicycle dealer, where I bought my older 2 singlespeeds, and later on converted these to fixed gear, being 15-20 years in this business, last summer claimed that roller chains link plates stretch and that this is the elongation, even after I explained the inner wear and added that I disassembled an old chain and could see how the pen holes became oval.

I dont think they use this argument to sell chains. Ive worked in the food Industy for 40 years and extensively purchased a range of chains from 3/8 pitch up to 1.1/4 pitch from the likes of Renolds down the scale to cheaper brands. I cant tell you how many feet of chains I've brought, but I used to order 10x 25ft boxes at time of say 3/4 pitch, hundreds of feet of various sizes every year As an engineering buyer at the time, no rep or company ever suggested preloading chaiins was necessity and none of the probably 100 engineers I've worked with even mentioned it either. Im sure there will be data to prove its uses in very certain conditions or applications but its just not widely used IME. It's a very interesting post but the subject wont even remotely make me want to deliberately pre,load a bike chain.

 

[Globalti]

Well apart from the few who ride SS, no cyclist is ever going to notice the effect.

 

[silva]

Some advertisements are funny though, and in the bicycle/motorcycle chains selling business:
"anti-fatigue"
"pre-stressed"
"pre-stretched"
and all 3 together.
https://www.ebay.com.au/itm/RK-428H...047027?hash=item282f3a6173:g:QlUAAOSwdGFY1IW8

"A heavy duty chain which is manufactured from Carbon alloy steel, heat treated and shot peened for maximum strength and durability.
Heavy Duty non O-Ring chain
The chain is pre-stressed and pre-stretched for superior performance and minimal elongation during the life of the chain."

The degree of misleading here is topnotch. Even that "Carbon alloy steel", alike it is a special steel grade or so, while iron+carbon alloy is what steel is.
That's why I started to dislike KMC. They also use such bullshit terminology, ex "Rust Buster Technology" instead of just "zinc plated". Or its later relabeling to "EcoProTeq".

In the end, the chain tensioning problem is due to no derailer/tensioner (springbased), a singlespeed can have one but a fixed gear not, reason being ability to resist pedals in order to slowdown which would wreck the tensioners mount due to force direction being opposite. I wonder if there really is no solution for this.

 

[gbb]

Some advertisements are funny though, and in the bicycle/motorcycle chains selling business:
"anti-fatigue"
"pre-stressed"
"pre-stretched"
and all 3 together.
https://www.ebay.com.au/itm/RK-428H...047027?hash=item282f3a6173:g:QlUAAOSwdGFY1IW8


The degree of misleading here is topnotch. Even that "Carbon alloy steel", alike it is a special steel grade or so, while iron+carbon alloy is what steel is.
That's why I started to dislike KMC. They also use such bullshit terminology, ex "Rust Buster Technology" instead of just "zinc plated". Or its later relabeling to "EcoProTeq".

In the end, the chain tensioning problem is due to no derailer/tensioner (springbased), a singlespeed can have one but a fixed gear not, reason being ability to resist pedals in order to slowdown which would wreck the tensioners mount due to force direction being opposite. I wonder if there really is no solution for this.

Funny how chain for sports or leisure equipment attracts the need for that kind of descriptive embellishment, where just good old Industrial chain made by reputable manufacturers relied on simple reputation built on quality so no need to embellish.
So who's to blame ?...perhaps you could argue the end user who buys into this cr&p. In a similar way, you dont really see this rubbish from say Shimano, they rely more on their reputation.. The answer is simple...seek out the quality, see through the bull.