Thorn Cycles Forum

Technical => Transmission => Topic started by: Danneaux on December 25, 2016, 10:05:18 PM

Title: Chainwear indicators/measuring tools
Post by: Danneaux on December 25, 2016, 10:05:18 PM
Santa arrived with a small but very welcome prize for me -- a Shimano TL-CN42 chain-checker:
https://www.sjscycles.co.uk/tools/shimano-tlcn42-chain-wear-indicator-y12160000/?geoc=US
It is a design that tensions the rollers on the same side so real stretch (wear) can be measured:
(http://www.evelostore.com/userfiles/images/Gallery/10005/2016-07-19/211693_tl-cn42_eng.jpg)

It is a go-no go design, but seems to work well for determining when the chain has stretched to a point where further use would cause undue drivetrain wear. Of course, I have measured every chain in sight and checked it against my usual method of comparing to a rule to be sure!  ;D

Hoping you all received some nice bike goodies from Santa as well.

All the best,

Dan.
Title: Re: Chainwear indicators/measuring tools
Post by: Andre Jute on December 26, 2016, 01:26:47 AM
Santa arrived with a small but very welcome prize for me -- a Shimano TL-CN42 chain-checker:
https://www.sjscycles.co.uk/tools/shimano-tlcn42-chain-wear-indicator-y12160000/?geoc=US

Does it work on any chain or only Shimano models, Dan?
Title: Re: Chainwear indicators/measuring tools
Post by: Danneaux on December 26, 2016, 02:01:30 AM
Works a treat on any chain, Andre. I just used it on my tandem's timing chain and confirmed my other measurements showing it is right at the point of replacement. It works on my Deda, Taya, KMC, Sedis, SunTour (yes, I still have a few...) and Regina (those too!) chains, so not Shimano-specific.

It is perhaps the nicest of the same-sided checkers to use, simply because it is so easy. You don't need two hands, simply engage the spring end and just sort of drop the tooth on the chain. The instructions included with my TL-CN42 say, "If the tool is pressed forcibly in Step2, the diagnosis will be inaccurate. Lightly apply the tool on the chain". Gently carries the day here and the weight of the tool itself seems to be plenty to engage the tool's tooth if the chain is sufficiently worn.

It looks like it would be as nice to pack on a long tour as it is to use in the shop at home. A really ingenious design, brilliant in its simplicity. I especially like the loss-proof laser-etched pictographic instructions on the tool itself. It works on the top or bottom run of chain and so far, gets full marks from me

If you shop carefully (as I er, "Santa" did), you can find them for about half price, well worth it for the convenience and speed.

Addendum: The Shimano TL-CN41 ( https://www.amazon.com/Shimano-TL-CN41-Chain-Wear-Indicator/dp/B00346ZEOE ) gives the same results, but I found it more awkward to use, requiring two hands to get it placed correctly; same with the Pedro's chain checker ( http://pedros.com/products/tools/general-tool/chain-checker-plus/ ).

For a nice treatise on the need for same-sided chain checkers and why they are more accurate, see: http://pardo.net/bike/pic/fail-004/000.html

All the best,

Dan.
Title: Re: Chainwear indicators/measuring tools
Post by: Andre Jute on December 26, 2016, 03:06:33 AM
Works a treat on any chain, Andre.

I looked into it, read the fascinating link you provided, and decided against it. For the gauge, if I ran my chains to the limit, I could recover the cost in five chains. Against the gauge, I use an inexpensive chain (KMC X8) every few years. I'd be dead before I recovered the cost.

But that isn't the main reason. On the principle that the chain is the cheapest wearing part in my transmission, and I don't want a worn chain wearing my sprocket or chainring, with the associated bother of replacing either, I replace the chain at 0.5mm wear. This is part of the system I've built for a near-zero maintenance bike. Thus it is irrelevant to me, as a low mileage, near-zero maintenance cyclist, whether a better gauge would permit greater precision in observing the wear of chains. I throw off the chain before precision in wear ever becomes relevant.

If I were a high mileage cyclist who fitted new chains often, of course I might take a different view.

Thanks all the same for providing input to come to a reasoned decision, Dan. I'm sure that in your hands, a high-miler, the gauge will soon recover its capital outlay.
Title: Re: Chainwear indicators/measuring tools
Post by: Danneaux on December 26, 2016, 03:28:39 AM
Quote
Thanks all the same for providing input to come to a reasoned decision, Dan. I'm sure that in your hands, a high-miler, the gauge will soon recover its capital outlay.
Very welcome, Andre. Yes, I can pretty easily do 9,000km in four months of summer riding, so I need to keep an eye on my chains' wear while stretching them as far as reasonable without imperiling chainrings and cogs. At USD$20 on sale, the checker is a pretty good deal for me.

That said, I see why "early" replacement works well for you Andre, and how it eliminates much hassle and reduces wear to levels even below what this gauge can indicate.

All the best,

Dan.
Title: Re: Chainwear indicators/measuring tools
Post by: Matt2matt2002 on December 29, 2016, 05:34:38 PM
Thanks for this tip Dan.
Santa left me some money so I'll splash the cash on one.

BTW my notes tell me I have done 6,718 miles on my chain - KMC X1.
Always within a Chainglider. Put on to new front and rear cogs.
Always run on the slack side.

I'll let you know the results when I have measured the chain.

Matt
Title: Re: Chainwear indicators/measuring tools
Post by: alfie1952 on December 29, 2016, 06:58:46 PM
I have the Caliber 2 chain wear indicator which is the same type of tool. I have just checked my SportsTour which has I believe 4100 km on a SLT99 chain with almost no wear. I recently fitted a KMC X1 on my Nomad but doubt if this will wear as well as the Rohloff chain.

Alfie
Title: Re: Chainwear indicators/measuring tools
Post by: Danneaux on December 29, 2016, 07:47:04 PM
Quote
I have the Caliber 2 chain wear indicator which is the same type of tool.
<nods> Yes, the same type, but the Rohloff works by pushing the rollers apart, which will result in earlier replacement of the chain than indicated by tools that push on the same sides of the rollers.

This is no bad thing for drivetrain lifespan, as it offers a wider margin of safety. The downside is earlier chain replacement than may be absolutely necessary. Again, as shown by Andre's experience, this will guarantee extended life for chainrings and cogs and as he mentioned, chains are cheap compared to other components. Chain cost assumes greater importance if one consistently puts in high miles. An additional argument can be made for early replacement, as indicated by the Rohloff tool: On derailleur applications a worn chain also becomes more flexible laterally, and this can cause shifting performance to degrade. A nice thing about the Caliber 2 is it has two scales -- one for drivetrains with aluminum alloy cogs and the other for steel. When used on a steel-cog drivetrain, the aluminum indicator will give a nice heads-up of early wear (0.075mm vs 0.1mm) so you can have a new chain at the ready when the steel side indicates replacement in a little while longer.

Chain wear indications made by opposite-side and same-side tools will vary. One isolates roller wear, the other does not. The Rohloff diagram here... https://www.rohloff.de/fileadmin/_migrated/content_uploads/Beschreibung_Caliber2_de_en_it_fr_nl_es.PDF ...shows how the Caliber 2 pushes the rollers apart, rather than measuring from the same side. Either is a valid measure of chain wear, but will not give the same results.

All the best,

Dan.
Title: Re: Chainwear indicators/measuring tools
Post by: jags on December 29, 2016, 10:56:59 PM
Oh Lord i just checked the price on that thing 29.99 are they having a laugh .
would a fella not be better off making one himself from a piece stainless steel when you buy a new chain  obviously. :o

anto.
Title: Re: Chainwear indicators/measuring tools
Post by: Danneaux on December 29, 2016, 11:17:19 PM
Quote
...would a fella not be better off making one himself...
The checking tools are mostly a convenience, Anto. Up till now, I've just hung the chain from a nail and used a measuring stick/rule/meter or yardstick to check chain wear. It has worked well and cost nothing.  ;)

All the best,

Dan.
Title: Re: Chainwear indicators/measuring tools
Post by: Andre Jute on December 29, 2016, 11:22:12 PM
BTW my notes tell me I have done 6,718 miles on my chain - KMC X1.
Always within a Chainglider. Put on to new front and rear cogs.
Always run on the slack side.

What was your previous chain, and what mileage did you get on it, Matt? (Or do I remember correctly, the Thorn is your first bike?)

Even if you're heavy on transmissions, as I am, it seems to me you will have to get at least half that mileage again to justify the price of the X1, unless it has some other advantage than extra longevity. (Nothing to do with the cost of the gauge which is the subject of this thread,  though it would be a nice thing to have if you're a toolfondler; I had to restrain myself mightily from buying the thing anyway, just to have it.)

Chain on the slack side is better than on the tight, according to the Rohloff manual.
Title: Re: Chainwear indicators/measuring tools
Post by: mickeg on December 29, 2016, 11:46:09 PM
Thanks for posting, I was unaware anyone made a tool that took both measurements from the same side.

I might check a chain about two or three times a year, and then do it when I have the chain off the bike anyway.  So, I think I will stick with the old fashion method of using a really long ruler.
Title: Re: Chainwear indicators/measuring tools
Post by: alfie1952 on December 30, 2016, 02:27:49 PM
As you say Dan it is just a convenience,  your TL CN42 would give a truer measure of chain wear. I  still measure stretch with a steel rule, I do not have the money to replace expensive chains when not needed. Recently I bought a KMC B1 chain, very cheap and was wondering if anyone is using this chain and what are their opinions on it.

Wishing you all the best for the new year. :)

Regards Alfie
Title: Re: Chainwear indicators/measuring tools
Post by: mickeg on December 30, 2016, 03:57:09 PM
... Recently I bought a KMC B1 chain, very cheap and was wondering if anyone is using this chain and what are their opinions on it.
...

I always buy the cheapest KMC chains, I have no idea if I ever used a B1.  But quite frankly since I get the cheapest ones, I am quick to replace them instead of push them to the point where they wear out other parts.
Title: Re: Chainwear indicators/measuring tools
Post by: aj on January 15, 2017, 08:54:44 AM
Quote
...would a fella not be better off making one himself...
The checking tools are mostly a convenience, Anto. Up till now, I've just hung the chain from a nail and used a measuring stick/rule/meter or yardstick to check chain wear. It has worked well and cost nothing.  ;)

All the best,

Dan.

so its not necessary to get the rohloff specific chainwear tool?
Title: Re: Chainwear indicators/measuring tools
Post by: Danneaux on January 15, 2017, 09:29:05 AM
Quote
so its not necessary to get the rohloff specific chainwear tool?
I would say it is important to have some way of measuring chain stretch over time so the chain can be replaced before it wears and elongates enough to cause damage to chainrings and cogs/sprockets. For many years, I used a ruler with some care and came out fine.

I recently bought a chain checker for convenience (quick checks at home) and to take along on lengthy tours where my ruler method is not so wieldy.

There's many good chain checkers available, and all give some fairly consistent indication of chain wear. However, the method by which they work (and the amount and kind of wear they indicate) can vary, so it is a matter of choosing one you are comfortable with. Some fail to take bushing wear into account, others do. Some indicate an early need for replacement (thus sparing the more expensive parts of your drivetrain), while others allow you to maximize chain life (thus saving on chain replacement).

As mentioned above, a good treatise on the different types and dis/advantages of each can be found here:
http://pardo.net/bike/pic/fail-004/000.html

In my opinion, the Rohloff chainwear tool is a well made, precision instrument that can be regarded as reliable. I simply chose a different model that was better suited to my needs as a high-mileage cyclist, where I would like to maximize chain life without risking the rest of my drivetrain unduly. Because I paid less than half price, it was a good value for me. I will use it on my derailleur as well as Rohloff drivetrains (and will also check using my trusty ruler at larger intervals). As far as chain checkers go, you can choose pretty much any model that appeals, but keep in mind the two different designs give different indications of wear. Unless dropped, damaged, or unusually worn checkers of the same type will give a consistent result, but measurements made with two different types will not give comparable indications.

Best,

Dan.
Title: Re: Chainwear indicators/measuring tools
Post by: aj on January 15, 2017, 09:30:56 AM
thanks, Dan!
Title: Re: Chainwear indicators/measuring tools
Post by: Javier on January 15, 2017, 07:22:09 PM
At 29.99 the Shimano TL-CN42 Chain Wear Indicator might be an investment for a bicycle workshop that checks in a hurry thousands of chains a year (and by then it could be worn out), but for me it is a waste of my money, when I can use a proper measuring tool, a caliper. I use my trusty Mitutoyo caliper to check the chain wear, nothing more accurate if you know what you are doing. If I had not had one I would buy on ebay a $10 digital steel caliper made in China that are reliable enough for this sort of accuracy, and as a bonus you get a multi-task tool that can be used for a plethora of other measurements, for example, to check how accurate are any chain wear indicator tools in the market. The only use of a chain wear indicator is checking chain wear and taking space in my tool box.
Just my humble opinion.
Title: Re: Chainwear indicators/measuring tools
Post by: aj on January 16, 2017, 02:21:00 AM
Quote

recently bought a chain checker for convenience (quick checks at home) and to take along on lengthy tours where my ruler method is not so wieldy.




How do you check your sprockets, Dan?
Title: Re: Chainwear indicators/measuring tools
Post by: Danneaux on January 16, 2017, 06:30:27 AM
Quote
I use my trusty Mitutoyo caliper to check the chain wear, nothing more accurate if you know what you are doing.
Yep, a precision instrument. I use mine regularly for a variety of tasks. Sure, it will work fine for checking chain elongation if you already have one. I like my Starrett inside, outside, and vernier calipers for some uses, also. They're nice for checking dropout spacing when I build frames.
Quote
At 29.99 the Shimano TL-CN42 Chain Wear Indicator might be an investment for a bicycle workshop that checks in a hurry thousands of chains a year...
I guess I got a bigger bargain than I thought, as mine was 19 postpaid, little enough for me to take the risk so I'd have a quick-checker to carry on multi-month tours. I have a weakness for tools and comfort myself with the knowledge this one can be used on all the bikes in my fleet -- and twice on my tandem. :D
Quote
How do you check your sprockets, Dan?
I make a couple checks:

What I first look for is shiny wear marks and any early signs of "tooth hooking" in the cog/sprocket drive faces when I clean my chain.

I then use my fingernail(!) as a gauge. If my nail snags at all or slows as it approaches the tooth end when moved from base to peak, it is time to reprofile or replace the cog. The worn tooth will look a bit like this, but less exaggerated: )\

If the tooth profile is sound, my nail will slide right off the tapered peak, which will look like this:  /\

Since I already have a digital caliper, I also measure between the tooth faces across the wear points to see how much they vary from spacing at the valleys. I used to keep a small section of chain made up from the trimmed ends of too-long chains. I'd wrap it 'round a cog and shine a light behind to see if there was space between the rollers/teeth and where. It was a quick check to see if old chains had worn the cogs at a larger diameter. I stopped using this method because any wear visible this way was already obvious by other means.

I can avoid replacing cogs/sprockets for a long time if I am careful to replace chains before the chains become too worn. Because they are larger and turn 'round less frequently, my chainrings tend to outlast my cogs, even though they are usually made of aluminum instead of steel (I use a stainless steel chainring on my Nomad. The triple crankset on my rough-road randonneur uses middle and inner chainrings made of steel to compensate for their small diameters). I still check them for hooking at every chain cleaning, just as I do my cogs.

On my Nomad, the sprocket and chainring can both be reversed to present fresh tooth drive faces to the chain.  I'm not so lucky on my derailleur bikes, because the cogs and chainrings cannot be reversed for longer life. On those, I use other means to extend drivetrain life...

Most of my randonneur bikes and the tandem are still equipped with 5-, 6-, or 7-sp freewheels, which are fairly thick and have proven long-lived in my use. All my rando bikes are setup with half-step and granny gearing and so my most-used cruising gears run as much in a straight line as possible, with minimal deflection. I use physically large chainrings and cogs in these gears, and that distributes wear over a greater number of teeth...usually a 50/45/24, 48/45/24, or 46/42/24 chainset coupled with 18-24t most-used cogs. My fast, light cadence makes up for the low gearing in these combinations and I typically cruise at 17-21mph/27-34kmh in 58-62 inch gears with a cadence of 110-120rpm. I find this comfortable and it eases the strain on knees damaged in a youthful car crash. I also think spinning (fast, light, round even pedaling) is easier on drivetrains than mashing (low-rev, cyclic pedaling with high periodic torque loads).

At the first sign of hooking on the teeth of my most-used freewheel cogs I pull them, clamp them front-to-front (flat face to flat face) against my new reference cogs, and use a high speed die-grinder to reprofile the worn teeth. This is possible because my freewheel cogs have simple, fairly thick teeth without the kind of contouring or twisting you see on cassette cogs. Occasionally -- depending on how much the cog has worn -- I will reheat the reprofiled cog with my torch and quench it in oil to heat-temper and harden the surface. So long as the tooth profiles can be re-established, the cogs can be reused. Eventually, I replace worn cogs with my spares. Replacing my chains before they stretch too far minimizes wear on the cog/sprocket teeth and extends their useful life. See "Sprocket Replacement and Restoration" here: http://www.sheldonbrown.com/freewheels.html

On my cassette cogs, I simply replace the entire cassette when the teeth on my most-used cogs show wear. Early cassettes were bolted together and individual replacement cogs were available but alas, those days are gone. I used to grind off the rivets of worn cassettes and store the "good" cogs for later in case I needed them...but never did, because those weren't the cogs that wore out first!

Sheldon Brown's site also contains a useful treatise on chain wear written by the late Jobst Brandt: http://www.sheldonbrown.com/brandt/chain-care.html

Best,

Dan.

Title: Re: Chainwear indicators/measuring tools
Post by: aj on January 16, 2017, 06:36:49 AM
thanks Dan, very informative.