Chain checker

Mark Alexander
Mark Alexander Posts: 2,277
edited July 2010 in Workshop
After a visit to my BS to check the drive chain on my TT bike I was recommended to check my chains so I have bought a checker. I got the Park tools one as it was recommended but I think that I'm being thick. Every time I try to use it it goes straight to 1.0 on all of my bikes. this includes the TT bike which I know is .75.

I think that I am doing something wrong. Although I am a bloke I did read the destructions. Sorry for admitting that I feel ashamed.
http://twitter.com/mgalex
www.ogmorevalleywheelers.co.uk

10TT 24:36 25TT: 57:59 50TT: 2:08:11, 100TT: 4:30:05 12hr 204.... unfinished business

Comments

  • topdude
    topdude Posts: 1,557
    Try the simple method, using a steel rule and the chain under tension measure a 12 inch length from the edge of one pin to the same point 12 inches on.
    If it is less than 1 sixteenth over it is ok,
    More than 1 sixteenth over consider it worn,
    1 eighth over is very worn and would need a cassette as well.

    The trouble with a chain checking tool is it includes wear in the rollers as well as overall wear so is not a reliable test.

    Another way of looking at it is to consider chains as consumables and change them more often rather than wait for them to wear.
    He is not the messiah, he is a very naughty boy !!
  • no-mates
    no-mates Posts: 31
    I went to my LBS for a chain wear indicator and he told me to do this. Big ring on front and small cog at back. Grab the chain at the 3 o'clock location and if you can pull it far enough away to see daylight its's shot.
  • keef66
    keef66 Posts: 13,123
    no-mates wrote:
    I went to my LBS for a chain wear indicator and he told me to do this. Big ring on front and small cog at back. Grab the chain at the 3 o'clock location and if you can pull it far enough away to see daylight its's shot.

    Either that or your chainring's buggered.
  • keef66
    keef66 Posts: 13,123
    "The trouble with a chain checking tool is it includes wear in the rollers as well as overall wear so is not a reliable test" - not sure I really understand this. Are you saying a chain with worn rollers is still OK and not contributing to sprocket wear? Surely if the rollers are worn enough to contribute to the measurement, the pins and side plates will be similarly worn?


    I use a Park Tools checker and find it to be quick and convenient. I need reading glasses and very good light to see sixteenths on a steel ruler; the Park Tool checker is Fisher-Price simple. In my experience with 4 bikes it won't drop in with a new chain, and it takes quite a while to get from new to 0.75 and then to 1.0.

    I treat chains the same way as tyres and brake blocks; check frequently and replace when worn out
  • neeb
    neeb Posts: 4,473
    My park tools chain wear indicator (the one that goes from 0 to 1 with the pivoting bit) always overestimates wear, and I think the problem is they will all be a bit different as if the pins aren't exactly straight they will be out by quite a bit. I guess it would be possible to calibrate it by bending one of the pins with pliers... The other park tools checker, the simple one that has 0.75 on one side and 1.0 on the other, is more reliable IMO, although as said above it is measuring roller wear as well as "stretch". Still, it's useful for keeping an eye on the chain, if you then conform wear with a ruler. The latter always seems to be a fiddly and messy job as you have to make sure the chain is pulled straight and line up the ruler precisely, etc.
  • topdude
    topdude Posts: 1,557
    Regarding wear in the rollers and pins.
    I find the rollers wear quite quickly, there is generally very little movement in them on a new chain but after a few hundred miles they can be fairly sloppy even with careful cleaning and lubing. But, slop in the rollers alone is not a problem as the "pitch" of the chain (distance between links) is still 1/2 inch.
    What is a problem is wear in the pins and bushings as this increases the "pitch" and causes accelerated wear of he chainrings and cassette. So, if a 12 inch length of chain (24 links) is longer than 12 inches there is wear in the pins and bushes.
    Up to about one sixteenth of an inch over means change the chain now to reduce wear on the sprockets, more than one sixteenth of an inch over and it is too late, everything will be worn and may need replacing.
    So, why does wear in the chain matter ?
    An unworn chain with a half inch pitch exactly matches the pitch if the teeth on the chainrings and cassette so the stress applied by you pedalling is distributed evenly around the teeth. A worn chain with a greater than half inch pitch is putting all the stress on only one tooth at a time on the chainring and cassette causing accelerated wear.

    Of course you can ignore checking the chain at all and run the drivechain to destruction where the chain and sprockets become totally worn but still working if you prefer, (ever checked a chain on a neglected old bike ? It can be half a link longer than a new one)

    Anyway, sorry for the lengthy post and honestly it is not difficult to use steel rule :wink:
    He is not the messiah, he is a very naughty boy !!
  • soveda
    soveda Posts: 306
    topdude wrote:
    Regarding wear in the rollers and pins.
    I find the rollers wear quite quickly, there is generally very little movement in them on a new chain but after a few hundred miles they can be fairly sloppy even with careful cleaning and lubing. But, slop in the rollers alone is not a problem as the "pitch" of the chain (distance between links) is still 1/2 inch.
    What is a problem is wear in the pins and bushings as this increases the "pitch" and causes accelerated wear of he chainrings and cassette. So, if a 12 inch length of chain (24 links) is longer than 12 inches there is wear in the pins and bushes.
    Up to about one sixteenth of an inch over means change the chain now to reduce wear on the sprockets, more than one sixteenth of an inch over and it is too late, everything will be worn and may need replacing.
    So, why does wear in the chain matter ?
    An unworn chain with a half inch pitch exactly matches the pitch if the teeth on the chainrings and cassette so the stress applied by you pedalling is distributed evenly around the teeth. A worn chain with a greater than half inch pitch is putting all the stress on only one tooth at a time on the chainring and cassette causing accelerated wear.

    Of course you can ignore checking the chain at all and run the drivechain to destruction where the chain and sprockets become totally worn but still working if you prefer, (ever checked a chain on a neglected old bike ? It can be half a link longer than a new one)

    Anyway, sorry for the lengthy post and honestly it is not difficult to use steel rule :wink:

    Wouldn't the distance between rollers effectively increase and so give you an artificially low pitch as the "effective" pitch would actually be longer (given that the cogs engage with the rollers rather than the side plates of the chain)?
  • neeb
    neeb Posts: 4,473
    Wouldn't the distance between rollers effectively increase and so give you an artificially low pitch as the "effective" pitch would actually be longer (given that the cogs engage with the rollers rather than the side plates of the chain)?
    I assume the wear on the rollers is on the inside, where they turn on the pins. If you think about it, this just means that they will move sideways when they are under tension on the sprockets, but assuming they are all approximately equally worn, they will all move sideways by about the same amount and the distance between the outer surfaces of the rollers where they contact the sprocket teeth will be the same. I guess if the rollers were worn on the outside (no idea if this happens or not) then the distance between the outer surfaces of two adjacent rollers could increase even if the chain pitch was the same, thus causing wear on the teeth (..?)
  • John.T
    John.T Posts: 3,698
    Most roller wear is on the inside so does not affect pitch. Some will be on the outside but as this will be more or less even round the roller it also will not affect pitch. It is wear in the pins and bushing that lengthen the chain.
    The Park tool pushes the rollers apart so adds twice the roller wear to the pin wear. Not a reliable tool.
  • balthazar
    balthazar Posts: 1,565
    edited July 2010
    It's not just roller wear, but roller clearance, which is an imprecise quantity from new, and may vary between different chain designs. It is perplexing that these gizmos, which fail in the single thing they exist to do, are still available. However, the old "lift the chain from the chainring" approach is even worse: you may as well ask your granny to read your chain wear in her tea leaves. Use a ruler! It's the precision instrument here.
  • andrew_s
    andrew_s Posts: 2,511
    Some unused chains will show 1% wear on a normal chain checker.

    If you want quick and easy together with the accuracy of a ruler, you have to stump up £45 for the Shimano chain checker, which has a 3rd prong to ensure that the rollers it's measuring between are pushed in the same direction.
    A steel ruler is a lot cheaper and nearly as quick.
  • huuregeil
    huuregeil Posts: 780
    I find the Park 0.75/1.0% go/no-go checker super convenient. Who cares if it's not strictly accurate?! Chains cost, what, something like £1 per 100miles, so £50 for a 5000 mile year. If I squeeze a couple of extra hundred miles out of a chain, it's nothing in the grand scheme of thing (i.e. compared to my annual cycling budget!). If you change after 0.75 but before 1.0, then you won't bugger your cassette, simple. I like pragmatic engineering, the park tool is a pragmatic tool! A new cassette blows the annual chain budget out of the water: far better to be conservative with chains.
  • John.T
    John.T Posts: 3,698
    Who cares if it's not strictly accurate?!
    When it can fail a new chain I do. I want something that will tell me acurately that it is time for a new chain (or not) and a 50P ruler does that perfectly.
  • huuregeil
    huuregeil Posts: 780
    Fair enough, I guess it depends on your chains, but I've never had mine fail a new chain (Campag Record or Veloce generally) and when the guage tells me its time, the ruler test comes pretty. Maybe if other chains have sloppy roller tolerances, then it's a different story.