Chain checkers.

[Alan Frame]

....are they accurate ?

'cos if they are, I may have a problem.

Just checked two chains, both have which have barely covered 1k miles....one is >1mm "stretch" and the other is .75mm.

Neither bike has any gear-related issues and sprockets and chainwheel teeth look in fine fettle.

I will be changing both chains as soon as I can, but I have a couple of questions:

- are chain checkers horrendously inaccurate [mine is a BBB model] ?
- would a KMC last longer than 1K miles as the manufacturer-fit on my Kona Sutra and Claud Butler Urban 300 don't appear to have lasted too well, despite loads of tlc and Mickleing ?

 

[PpPete]

I've read some discussion somewhere, can't remember where, that says they are not accurate (even the Park ones), and are measuring between the wrong bits on the chain. However, since the only checking tool the article recommended as accurate was humongously expensive I didn't bother going further into it.

By the way isn't it 0.75% and 1% (not mm) ?

Chains are frequently one area (along with tyres) in which bike manufacturers economise. I would certainly expect at least 3k - 5k miles out of even a ordinary quality KMC chain.

 

[Alan Frame]

I've read some discussion somewhere, can't remember where, that says they are not accurate (even the Park ones), and are measuring between the wrong bits on the chain. However, since the only checking tool the article recommended as accurate was humongously expensive I didn't bother going further into it.

By the way isn't it 0.75% and 1% (not mm) ?

Chains are frequently one area (along with tyres) in which bike manufacturers economise. I would certainly expect at least 3k - 5k miles out of even a ordinary quality KMC chain.

Thank you for the reply,

Yes, you're right, it's a %, not mm. Must be the shock of finding out both chains are knackered. Bit like the rider !

Think I've seen it advocated somewhere to use a trusty old steel ruler to measure, but I'm so cack-handed I don't think I'd trust myself to be any more accurate than the chain checker.

 

[benb]

Take it to a LBS and ask them to check it with theirs to see if it agrees. 1k miles is very poor, and would indicate to me that something is not quite right.

 

[Alan Frame]

Take it to a LBS and ask them to check it with theirs to see if it agrees. 1k miles is very poor, and would indicate to me that something is not quite right.

I've lost confidence in both chains now, so they will be changed anyway.
I've never had any problems with the gears, so am I right in assuming that the something which isn't quite right is the chain itself ?

Must be made of cheese !

 

[e-rider]

I have the new park tools one and I have no reason to suspect that it is not accurate.

On a new chain it reads "no stretch"
After about 6-12 months it reads 0.5% stretch
And after 1 year it reads 0.75% stretch (time to think about a new one)

Considering the mileage I do, this is exactly the wear rate I would expect so I'm convinced that mine works fine!

It would definitely be worth checking the chains with another tool - perhaps yours slipped through the quality control checks and is a bit dodgy?

 

[Arsen Gere]

I have a chain checker in a box somewhere. It reports my chains are worn at 500 miles or so. I guess it depends on mileage and how hard you ride, acceloration, climbing etc. I know if I leave a chain on for more than about 2500 miles it's going to wear the chain rings and rear sprockets. FWIW I use Shimano chains are they are readily available and a bit of a known quantity to me. I still reckon the old fashioned method of pulling the chain away from the front chain ring gives a good feel for how worn a chain is.

 

[Alan Frame]

I have a chain checker in a box somewhere. It reports my chains are worn at 500 miles or so. I guess it depends on mileage and how hard you ride, acceloration, climbing etc. I know if I leave a chain on for more than about 2500 miles it's going to wear the chain rings and rear sprockets. FWIW I use Shimano chains are they are readily available and a bit of a known quantity to me. I still reckon the old fashioned method of pulling the chain away from the front chain ring gives a good feel for how worn a chain is.

Thanks for the reply. When I get the chance I think I'll try the manual chain pull technique...sounds sufficiently simple for me to cope.
What sort of "gap" should I be looking for ?

 

[SatNavSaysStraightOn]

Just got a Park tools one myself.
Both road bikes need new chains, mine immediately. my OH's is about 5 months old and has done roughly 1,000km through ice, floods and lots of mud (due to the lane we live on) and comes in at 0.75%. Mine has done over 1,800km, is 4 months old and easily fits the 1% mark.
Both mtbs are fine (as is my neighbours road bike which is stored with our bikes) and the tool does not apply to our tourers becuase they have rohloff hubs. I got 14,500km out of the last chain on my tourer, my OH got 9,500km.
I only purchased the tool because the chain on my road bike was looking "thinner" for want of a better expression, but I don't get any gear issues other than slow down gear changes which is a derailuer issue. I will be going over to the KMC Z51 (£4.49) change which we have on our tourers. It will be interesting to see how that lasts on a derailuer bike. Regretfully I will have to find a different chain for when my mtb needs a new one becuase the KMC Z51 is only a 7/8 speed chain and my mtb needs a 9 speed chain.

 

[Arsen Gere]

Thanks for the reply. When I get the chance I think I'll try the manual chain pull technique...sounds sufficiently simple for me to cope.
What sort of "gap" should I be looking for ?

If you can pull the chain away and see a gap between the chain and the top of a tooth at the 3 o'clock point it is well knackered. There will always be some play so you need to look at what a new chain looks like on your setup. It's not science really so I can't give you an exact measure. It's just a guide. Sheldon Brown has some nice picks and a more accurate guid here http://sheldonbrown.com/chains.html#wear

 

[Alan Frame]

Excellent, thank you all for your prompt replies !
I think I'm going to archive my BBB chain checker, invest in some KMC chains, pick Sheldon's brains [R.I.P.] and get me hands dirty tugging me chain.
Unfortunately, work beckons so that will have to wait a while.

Thanks again everyone.

 

[e-rider]

you could just buy a decent tool

 

[02GF74]

why should they be inaccurate? they are made by stamping out of a sheet of metal - just like the links themselves - yet nobody is claiming the links themselves are inaccurate and I bet many more links are made by the same tool (so the tool wears more) than chain wear tools.

I have faith in mine - once chain hits 0.75% wear it is binned and new chain is on, no skipping on cassette.

 

[andrew_s]

The only chain checker that is reliable is the expensive Shimano model.

All the others measure between a roller pushed to the right and a roller pushed to the left, and are therefore including the amount of roller movement in the result. That's OK if you are using the same chain as the checker manufacturer calibrated the checker against, but if you use a different model of chain you'll get a different answer.
In general, the maker will calibrate against a chain with tight-fitting rollers, because any error just means that you've replaced the chain earlier than need be, whilst if they calibrated against a chain with loose rollers people who had a tight roller chain may find that a new chain slipped despite having replaced at an indicated .75% stretch. This would generate complaints.
In the worst cases, a brand new chain can show as 1% stretched.

The most reliable method of checking chain stretch is to measure between pin centres over about 12 inches using a ruler. Pins on a new chain are 1/2 inch apart, so if the 12" pin on a used chain is at 12 1/8", you've got 1% stretch.

 

[mickle]

The only chain checker that is reliable is the expensive Shimano model.

All the others measure between a roller pushed to the right and a roller pushed to the left, and are therefore including the amount of roller movement in the result. That's OK if you are using the same chain as the checker manufacturer calibrated the checker against, but if you use a different model of chain you'll get a different answer.
In general, the maker will calibrate against a chain with tight-fitting rollers, because any error just means that you've replaced the chain earlier than need be, whilst if they calibrated against a chain with loose rollers people who had a tight roller chain may find that a new chain slipped despite having replaced at an indicated .75% stretch. This would generate complaints.
In the worst cases, a brand new chain can show as 1% stretched.

The most reliable method of checking chain stretch is to measure between pin centres over about 12 inches using a ruler. Pins on a new chain are 1/2 inch apart, so if the 12" pin on a used chain is at 12 1/8", you've got 1% stretch.

Roller rattle irrelevant then?