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Discussion Starter #1
For all the engineers and tool guys out there, here's a method to measure chain stretch using a 6 in. vernier caliper:

1) set the caliper at 5.6 in.

2) insert the inside measuring jaws between the chain rollers

3) extend the jaws to tension the chain and record the measurement

new chain = 5.715 in.
1/2% stretch (equivalent to 1/16 in. over 12 in.) = 5.745 in.
3/4% stretch (equivalent to 3/32 in. over 12 in.) = 5.760 in.
1% stretch (equivalent to 1/8 in. over 12 in.) = 5.775 in.
 

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The Punk Hucker
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I had never though of using my vernier to measure stretch. Probably the most precise way of doing it!!!
 

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billee said:
For all the engineers and tool guys out there, here's a method to measure chain stretch using a 6 in. vernier caliper:

1) set the caliper at 5.6 in.

2) insert the inside measuring jaws between the chain rollers

3) extend the jaws to tension the chain and record the measurement

new chain = 5.715 in.
1/2% stretch (equivalent to 1/16 in. over 12 in.) = 5.745 in.
3/4% stretch (equivalent to 3/32 in. over 12 in.) = 5.760 in.
1% stretch (equivalent to 1/8 in. over 12 in.) = 5.775 in.
At what point do you replace the chain? I was told the cassette should be replace with the chain. Good tip using calipers-thks
 

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Discussion Starter #7
JAKE61 said:
At what point do you replace the chain? I was told the cassette should be replace with the chain. Good tip using calipers-thks

According to Sheldon Brown, at 1% stretch the cassette and chain ring have probably been damaged. He recommends replacing at 1/2%.
 

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JAKE61 said:
At what point do you replace the chain? I was told the cassette should be replace with the chain. Good tip using calipers-thks
While it's usually best practice to replace the chain when replacing the cassette, the opposite isn't true.

Chains wear on their own schedule independent of the cassette condition, but cassette wear depends on the chain's condition, so running an old chain on a new cassette will cost you valuable cassette life.

With decent care, replacing chains well before 1% wear (many riders replace at 1/2%) a cassette should outlast 3-5 chains.

BTW- measuring stretch with a caliper this way shares the same problem that causes most of the wear gauges to read high. Roller float is included in the measurement, adding to the reading. If you want to use a caliper, measure from the outside plates instead. First measure from the front of a plate to the back of one about 6" away on a new chain to establish the zero reading. record that someplace where you won't lose it. Then you can repeat the measurement any time and the difference equals the stretch.

Don't forget to put some tension in the chain by pressing the pedals while not letting the rear wheel turn, otherwise you'll get a low reading.
 

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billee said:
For all the engineers and tool guys out there, here's a method to measure chain stretch using a 6 in. vernier caliper:

1) set the caliper at 5.6 in.....
All these years of riding, why didn't I think of this. I swear by the Parktool gauge but this will work just fine.
FBinNY said:
....With decent care, replacing chains well before 1% wear (many riders replace at 1/2%) a cassette should outlast 3-5 chains....
I replace at about the .75% mark, at the .85% mark things go downhill fast and my chain gets to the 1% mark within 2 weeks and usually break around that time.
 

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Discussion Starter #10
FBinNY said:
BTW- measuring stretch with a caliper this way shares the same problem that causes most of the wear gauges to read high. Roller float is included in the measurement, adding to the reading. .
I agree that the method I described produces higher length measurements than theoretical due to the two contact rollers being pushed in opposite directions during the measurement (and as you pointed out, the same happens with commercial chain stretch gauges) . However, the baseline length I listed for a new chain includes this effect so that the stretched readings are only in error by the amount that the radial float of two rollers increased due to wear. A few thousandths of an inch at most.
 

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Thanks for replies Billy&FB. I recently damaged my chain via a bad shift which bent a side plate and then the rivet came out. I took the bike and chain to the bike shop recommended from a friend that races mountainbikes. He always places in the top three so I figure he knows. Anyway he said to replace the cassette if you replace the chain. So I took the old chain along so they'd get the right chain length-they tuned the bike up but I got it back with the old chain-they'd put in a quick link(master link). I don't really like the looks of the link(weak link) as I don't want to get stranded. BTW the bike shifts good post tune-up. What thinkest ye? Can't they spin rivets for these chains? At a minimum i think I'll carry a spare link just in case. Am I a casual rider? I raced dirt bikes for many years-I figure I ride better than the majority. I don't pound my equipment, but I do go pretty fast. Background: recently acquired ' 99 K2 1000 with deore LX groupo(gift from friend). So I have a lot to learn on maintenance/tweaking etc. Just here to learn/sorry for the rant-seemed an appropriate thread to ask. Cassette has some wear but serviceable. Chain seems very stretched but with no baseline chain measurement...What's your feeling: run it or replace it? Thanks in advance-Jake
 

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To answer your first question, no you can't re-peen a pin after it's been pushed out and back. Even if you had the right equipment, the excess metal you'd need to flow out to make the rivet head is gone having been sheared off when you pushed the pin out.

As far as measuring your chain for wear, you don't need a base line measurement. The baseline is 1/2" or a multiple thereof (that's why it's called 1/2" pitch chain). Since it's now closed with a reusable master link, remove it and hang it vertically letting it's own weight stretch it out. Use a steel tape measure pin to pin over 4 feet of chain (96 links) and noting how far beyond 4' mark that pin is. By measuring over a longer distance the accumulated wear will be greater. ( 1/2% = 1/4" in 4 feet, 1% = 1/2" in 4 feet) with the wear magnified this way you won't need a precision instrument to know exactly how worn your chain is.

As far as the cassette is concerned, it's condition will mirror that of the chain, but I never suggest replacing cassettes until you try them with the new chain. If it runs smoothly and transmits power without skipping keep it, if not replace it.
 

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Ok-I'll take a measurement. Sounds like good advice: "If it works good-it's good." Save me money in the process. Now I need to see what they have in the way of chains. Thanks FB-Jake
 

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Picture

Here is a picture of a new chain vs a worn one.

The chains are both the same number of links and a little over 4' long. The worn chain failed on the Park chain gauge's 0.75% side but not the 1.0% side. From the picture it's easy to see that the worn chain is about 1/4" longer than the new one.

I got 2 seasons out of the chain, so even though the wear is only about 0.5%, I'm replacing it anyhow. Got my money's worth out of it and chains are cheap compared to cassettes.

I would guess that the reason the Park gauge showed 0.75% wear is that the rollers are worn.

Walt
 

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Good illustration-thks. My last Ride I was 5 -6 miles away from the truck at the farthest point. Considering the terrain, it would've really sucked to have had to walk back-I'm with ya on the chain. I can tell you from experience with motorcycles chain quality matters. I have a 450cc streetbike-just a cruiser. The chain it came with needed to be adjusted regularly and never stopped stretching to the point of aggravation(cheap POS). I replaced the chain with an EK triple Z chain made for 180hp crotch rockets. The chain was so hardened that when I installed it, it took a 6" C clamp to press the plate on the master link. I had the bike shop flange the rivet heads and their special tool wouldn't do it. So they put an X in the rivet heads with a hand sledge and chisel but even with that they hardly made a nick in it. They were amazed at the hardness of that chain. That was almost 3 years ago. Since then I've adjusted the chain twice(difference between a 60.00 chain and a 210.00 chain retail). I got it off ebay for 110.00-money well spent. I'll never buy a cheap chain again. Are all bike chains as junky as the one on my bike or do they have different grades? Any recommendations? I suppose a chain that hard would really tear up a cassette, but if only the rivets and rollers were super hardened.....I'll have to research a little and see what's out there.
 

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"I got 2 seasons out of the chain, " Wow, I have only about 200 miles on my XTR chain and I'm already getting major slipping. I replaced the chain and rear cassette with XTR about 3 months ago and I'm bumed that I'm already having issues with chain slip. Am I doing something wrong??? The bike shop says I have some wear left on the chain but not sure what side of the Parktool he used. I don't think he even used it correctly as I'm pretty sure I saw him try to insert the curved end in last... What are good chains to use??? I would think that the XTR chain would be great, but are they known for wearing out this fast??? Any help or advice on the chain selection would be great....:)
 

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There's no way the chain stretched enough to be the cause of your slipping, unless you did the Mt. Washington Hill Climb without any chain oil (and even then I still doubt it).

Satisfy yourself by measuring chain stretch with a 6-12" ruler. Since the chain is 1/2" pitch every link will line up exactly at 1/2" marks. With wear, the pitch is a bit longer, and over 6 or 12" the links will be out a bit more than expected.

Lean the bike on a wall where it can't roll. Tension the chain with some pedal pressure, and line up the ruler with either a pin or the forward edge of a plate, and note the position of the corresponding point 12" out. Less than 1/6" is still OK, 1/6" to 1/8" time to replace, and beyond 1/8" reaching the point of skipping and/or causing excessive sprocket wear. (if measuring less than 12" pro-rate the allowable stretch accordingly)

Note; measuring chains isn't a precision task, since you're working with an acceptable gray zone of 1/16" anyway, so don't sweat it.

Lastly, while measuring wear is good, the real issue is preventing it, and that's where good chain oil, and good maintenance come into it.

As far as what is causing the skipping, there are lots of possibilities, and knowing more, like the age of the bike, age of the cassette & chainrings and the age of the chain you replaced would help us help you.
 

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I just measured an old chain that I had taken off of my bike. I got results from 5.74 to 5.72. Quite a variation I thought. Part of the problem is the inability to measure from roller pin to roller pin every time. I think I will stick to a rigid rule, or more likely change it when I get around to it.
 
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