Workshop Stories: Chain Measure Tool

[Schwynn]

 

 

 

?

 

Anyone chipping in for a mass order of Blue rulers?

 

?

I'm going to order myself one - birthday in AugustThe missus is coming to SA (CT) 1ste week in August and this is small to pack so let me know.

 

Ag ou Varkie, sy gaan nie dalk 'n pr?m met 44cm K-wing handlebars in stoot nie, gaan sy?

[straatvark]

 

 

 

 

 

 

Anyone chipping in for a mass order of Blue rulers?

 

 

I'm going to order myself one - birthday in AugustThe missus is coming to SA (CT) 1ste week in August and this is small to pack so let me know.

 

Ag ou Varkie' date=' sy gaan nie dalk 'n pr?m met 44cm K-wing handlebars in stoot nie, gaan sy? [/quote']

 

- If you can retrieve it from CT, PM me

 

[Christopher Brunsdon]

 

 

 

 

 

 

Anyone chipping in for a mass order of Blue rulers?

 

 

I'm going to order myself one - birthday in AugustThe missus is coming to SA (CT) 1ste week in August and this is small to pack so let me know.

 

Ag ou Varkie' date=' sy gaan nie dalk 'n pr?m met 44cm K-wing handlebars in stoot nie, gaan sy? [/quote']

 

- If you can retrieve it from CT, PM me

 

Not to piss on anyones fires, but be careful of customs at CT. My mom came over a few months back and customs searched her - 1st time in 29 years that she has been coming back to SA (she lives in OZ).

 

She was fined for bringing in too much booze - if only they new that the extra litre of scotch was finished before I even got her to Somerset West ( and I was not the one drinking)

 

[straatvark]

 

 

 

 

 

 

Anyone chipping in for a mass order of Blue rulers?

 

 

I'm going to order myself one - birthday in AugustThe missus is coming to SA (CT) 1ste week in August and this is small to pack so let me know.

 

Ag ou Varkie' date=' sy gaan nie dalk 'n pr?m met 44cm K-wing handlebars in stoot nie, gaan sy? [/quote']

 

- If you can retrieve it from CT, PM me

 

Not to piss on anyones fires, but be careful of customs at CT. My mom came over a few months back and customs searched her - 1st time in 29 years that she has been coming back to SA (she lives in OZ).

 

She was fined for bringing in too much booze - if only they new that the extra litre of scotch was finished before I even got her to Somerset West ( and I was not the one drinking)

 

 

thanks, you are right, will keep the within the legal monetary limits. The rulers is perfect with size and price for that.

 

[splat]

I bought a steel rule a while ago, but missed the point a bit as it was in mm and not actually long enough.

 

I would like to get me one of these.

[slowtwitch]

ok so I've read the article stating that chain measuring tools are TOO CONSERVATIVE due to the fact that they include the wear of rollers (which does not add to chain length wear)

But as I understand it as shown in this pic, we're talking about an error of only one roller's wear not so?

Therefore the error of these tools are minimal, and surely not too conservative

[Johan Bornman]

ok so I've read the article stating that chain measuring tools are TOO CONSERVATIVE due to the fact that they include the wear of rollers (which does not add to chain length wear)

But as I understand it as shown in this pic' date=' we're talking about an error of only one roller's wear not so?

Therefore the error of these tools are minimal, and surely not too conservative

[/quote']

 

The fact that the tool is short exacerbates the error. All measurements include an error, but with the ruler method your error is minimised by the fact that it is over a larger distance. We're working with percentages here and if you make an error in a 4-inch measurement and that same error in a 12-inch measurement, the 12-inch measurement's error is in fact a 1/3 of the size of that in the 4-inch measurement.

 

GoLefty once expressed the phenomenum very elegantly but I forgot to remember it. Where's my ginko beloba?

 

[AndreZA]

JB, when are you getting you batch of blue alu rulers?

[Johan Bornman]

JB' date=' when are you getting you batch of blue alu rulers?[/quote']

 

I ordered a batch through one of my students and I must follow up with him. I never placed an order myself.  If anyone has an order going out soon, I'll chip in and get some rulers.

 

 

[slowtwitch]

So the issue is more about the length over which the wear is measured rather than the issue as stipulated in the document of roller wear measurement (and why does the doc refer to 2009 and on only?)

 

But what sort of error are we talking about then. are you implying that when a Park tool indicates 1%, the reality is only .67% and you can still get a thrid of the mileage more before changing chains?

 

[Matchstix]

good one JB nice rule to remeber

[Tumbleweed]

So the issue is more about the length over which the wear is measured rather than the issue as stipulated in the document of roller wear measurement (and why does the doc refer to 2009 and on only?)

 

?

 

But what sort of error are we talking about then. are you implying that when a Park tool indicates 1%' date=' the reality is only .67% and you can still get a thrid of the mileage more before changing chains?

 

?

[/quote']

 

 

 

good question. johan, i would like to see pics of the park tool measurements against those of the ruler. any chance?

[johannrissik]

As usual, Sheldon has said it all before:

Measuring Chain Wear

 

The standard way to measure chain wear is with a ruler or steel tape

measure. This can be done without removing the chain from the bicycle.

The normal technique is to measure a one-foot length, placing an inch

mark of the ruler exactly in the middle of one rivet, then looking at

the corresponding rivet 12 complete links away. On a new, unworn chain,

this rivet will also line up exactly with an inch mark. With a worn

chain, the rivet will be past the inch mark.

 

 

This gives a direct measurement of the wear to the chain, and an indirect measurement of the wear to the sprockets:

 

 

• If the rivet is less than 1/16" past the mark, all is well.

   

   

   

• If the rivet is 1/16" past the mark, you should replace the chain, but the sprockets are probably undamaged.

   

   

   

• If the rivet is 1/8" past the mark, you have left it too

  long, and the sprockets (at least the favorite ones) will be too badly

  worn. If you replace a chain at the 1/8" point, without replacing the

  sprockets, it may run OK and not skip, but the worn sprockets will

  cause the new chain to wear much faster than it should, until it

  catches up with the wear state of the sprockets.

   

   

   

• If the rivet is past the 1/8" mark, a new chain will almost certainly skip on the worn sprockets, especially the smaller ones.

At this stage I think it's time to ride....

 

 

[Johan Bornman]

So the issue is more about the length over which the wear is measured rather than the issue as stipulated in the document of roller wear measurement (and why does the doc refer to 2009 and on only?)

 

But what sort of error are we talking about then. are you implying that when a Park tool indicates 1%' date=' the reality is only .67% and you can still get a thrid of the mileage more before changing chains?

 

[/quote']

 

No. There are several issues.

 

An error of a mere 1% is big enough to mess up your sprocket. Yes, I am saying that all roller-based measurement tools give inaccurate readings and the sensible manufacturers build a safety margin in that errs on the conservative side. I have never quantified that margin since I don't know what it is.

 

I think the document you're referring to explains it nicely. Have another look.

 

[Johan Bornman]

good question. johan' date=' i would like to see pics of the park tool measurements against those of the ruler. any chance?[/quote']

 

I am sure you would like to see it. Why not just do it yourself?   

[Cicada]

Nice break down of the facts Johan!

 

Your technical input is always appreciated!

 

What does a blue Park Tool ruler retails for - any idea?