OK I'm sure this one has been asked before too but I have not been able to find it in a search.

How many miles should I put on a chain before it needs to be replaced? I will have over 2000 miles on this chain very soon. A friend told me that a chain should be replaced at around 2000. I will be touring Italy in the fall and will have well over 2000 miles by that time. I do not want to experience problems with my chain while on tour. Should I replace it?

I'd replace it and I'd want to give the new chain a little test before packing for Italy.

Chain life varies all over the board depending on it's use and maintenance. At least one race mechanic advises routinely replacing them at 1,000 miles so you don't have to worry about cassette and chainring wear.

I would go broke replacing chains every 1,000 miles! Properly maintained a chain will last many thousands of miles. Simply get out your chain gage and check it. Better yet, use a 12-inch quality steel ruler. When using a ruler place the end of the ruler centered over a pin. A new chain will be exactly 12 inches to the center of the pin 24 links away. The technical limit is 1/8 of and inch past 12 inches for 24 links. In order to keep my cogs and chain rings in good condition I replace the chain at 1/16 of an inch. Most chain gages have two sides, one for half worn at 1/16" stretch and second at 1/8" stretch which indicates completely worn out. Don't check only one part of the chain with a gage or ruler. Check several sections as chain can have differing worn areas. If I were going on a long tour in a far away place and my chain was stretched pass 1/16" I would go ahead and put a new chain AND cassette on the bike. Most reputable mechanics will tell you that chain and cassettes should be replaced at the same time but using 1/16" as the replacement limit will allow you to get away with reusing an old cassette or freewheel.

Chain life is not measured in miles, its measured in stretch, as n4zou very good post pointed out. If you are a very strong rider and hammer in the mountains only, you could stretch a chain in less than 1000 miles, maybe 500 miles.

If you take it really easy, hardly putting pressure on the pedals, it can last thousands.

Yeah, I usually get about 5000-6000 miles before a chain's worn to 1/8" stretch. I usually replace it before then, somewhere between 1/16 to 1/8", so around 4000-5000 miles.

Riding in the rain's the worst thing I've done to my chain. Maybe it's the water washing away the lubricant that causes it. So the chain's lubricated only with water on the ride. Even with cleaning & soaking the chain immediately after the ride doesn't help, the wear's already occurred.

Probably less the wet than the grit that the wet brings with it.

I go through several chains a year on my mountain bikes. They are ridden in dirt and wear quickly. Road bike lasts longer but still, i can only get around 3k on one. Other that conditions, the gear combos that you use most often will also effect chain life. Running constantly on one smaller cog will wear out the cog and then the chain, quickly.

If I were touring anywhere, I'm going with a new chain and cassette and probably cables, housings etc. No reason to be stingy.

change the chain and pack some replacements judst cheap chain

Wow advice all over the board (no pun intended). But thanks, I guess I will have to digest this all and decide for myself.


What are the differences between this chain checker and this chain checker?

If it is time to change the chain then does that mean it is time to change the cassette?

The $10 tool will show .75% and 1% chain "stretch" while the mroe expessive tool can show you wear down to .25%. Typically, everyone recommends changing the chain at 1/8 inch stretch over 12 inches, which works out to 1%. I guess you if you want to know how the chain stretch is progressing, buy the more expensive tool. I have the cheaper park tool but if you wanted to go even cheaper yet, a 12 inch ruler would do the job.

Beh... a ruler does the exact same thing as the chain checker things. What you are really interested in is how far the chain has deviated off the normal (rivets should line up exactly on 12") and then you have an acceptable stretch before you replace. 1/16"

You normally only replace a cassette if you've been lazy and let the chain really wear, which also screws up the cassette. This is characterized by the new chain slipping and otherwise being very crappy on your old cassette.

That is why it is better to replace chains than cassettes -> they cost less to.

Not always. If you are running a cheap cassette sometimes it makes sense to just wear the chain and cassette out together. Replacing chains to preserve cassettes only makes sense if you are running expensive cassettes like Dura Ace, etc. It becomes simple math really.

Since August of last year I have purchased two mtb cassettes and one road cassette. And I've lost track of chains but i think i have used 3 mtb chains and i'm on my 2nd road chain. Everything was replaced based on the chain checker recommendations and cassette skipping. Excluding the road cassette, i replaced it because i got new wheels and i run cheap cassettes so i figured, what the hey.

Chain Replacement,

NOW! What Portis said. IF you run a worn or stretched chain you will mess up your sprockets.
Chains are cheeper than sprockets.
As stated above, nobody knows how long your chain will last, Load, dirt and lack of lubricant will all be factors. Keep it clean and lubed. Like the man said, measure it, but get rid of it if it is stretched.
Right on Portis.

As chains have gotten thinner to handle more gears the life expectancy has decreased. My 7 speed friction shiftin wonder chains life is about 6,000 miles; but those of you on these types of forums that have more gears have reported an average of about 3,000 miles; the newer thinner "jewelry" chains for 21 speeds and up are reportedly to be only good for about 1,500 miles. I guess my question is why should we have to replace a chain more frequently then a tire? I think instead of going for a ride we're being takin for ride. Now I can't wait for the ride the bicycling industry is going to take us to next...electronic shifting, heehaw.

Electronic shifting isn't a bad idea, you just need a power source, and I would think the rear hub would be a good place for it, a small hub generator, which produces say +5VDC and -5VDC, this is sent to the shifter, which can return +5VDC to shift up, -5VDC to shift down, and 0VDC when not shifting. This powers a stepper motor which is either part of the deraileur, or is mounted on the chain stay with a short cable to the deraileur and does the actual shifting. Since you have eliminated the long shift cable, you eliminate a lot of the inaccuracy with the long cable. A thin flat wire would be less obtrusive as well..... Would electronically activated brakes be far behind???

TECHNICALLY speaking, chains don't stretch. They wear and as a result of metal loss on pins and bushings they get longer. Since the wear happens for the most part when the links are under load and BENDING/MOVING, I would expect to find wear on the arc of the chain when it changes direction as it starts the arc around the sprockets. On the jockey wheel side where you get the reverse direction arc happening there isn't much tension on the chain, hence the wear would be minimal...(of course, I'm assuming the chain is being looked after properly so the spaces aren't full of grinding paste)
As an experiment, I took a chain at the full stretch limit and flipped it over and ran it inside out. It BEHAVED like a chain that was within tolerances. The wear on pins, etc. is now on the outside arc of the chain and that's not where the tension is now. I'll report back with mileage on the chain over the course of the riding season.
My guess is, I can't expect double the mileage but I would think I can get another 50% at least.

Haven't heard of the hub gen thing yet,but that does sound far far better then the battery operated ones I heard about! Can't imagine a battery going dead while on a ride and being unable to shift.

I tried running a chain and cassette/freewheel into the ground and it worked, for years. When I changed the chain and freewheel, they meshed, but the chainrings had worn unevenly and were making tons of noise. I had to replace both chainrings, they looked like sharks teeth.

So if you want to preserve the chainrings, change your chain.

Agree with the second phrase, not with the first. I thought this too, that the ruler test does the same thing. NOT! Here's why. If the pins and side-plate bushing-shaped contact points are what's wearing, then yes, you'll be able to measure the wear with a ruler, because the chain will elongate overall from pin to pin. BUT if the major wear is happening on the *inside of the rollers*, then the length of space between the rollers will increase even though the distance from pin to pin won't change appreciably. That increased space between rollers will show up on a gauge, but not with a ruler, because the distance between pins hasn't changed much. A ruler can only measure the distance between pins. Not the length of the space between rollers! You need a gauge for that. I just found this out the hard way.

Flipping the chain is a well-known way of extending its life, though you here about it more often on singlespeed bicycles.

OK so the question still stands:

What are the differences between this chain checker and this chain checker?

Other than the cost.

true. there are so many factors involved but if a person wanted a hard number i'd say 2000 miles. back when i was riding hard i'd get about that out of the best sachs/sedisport chain.

ed rader

You might find the CC-3 easier to use. It gives you a "start thinking about it" reading (.75%) and a "change the chain already" reading (1%). I use a CC-3 myself, although I've used the CC-2 in the shop. At home for a quick check though, the simpler, the better as far as I'm concerned.

I am running an electronic shifting system now that I designed and built myself. The shift unit attaches to the down tube and utilizes the existing cable runs. Cams attached to small reduction gearboxes and stepper motors simply pull the cable the required amount to shift the front and rear derailleurs. This is all programmable using a simple and cheap basic stamp processor. The original shifters are kept on the bike as backup in case you forget to recharge/replace the batteries. The basic stamp processor can run for a month continually on a 9V transistor battery and stepper motor battery life is dependent on how often you shift. Four D size batteries run my system for at least a month. When required the stepper motor shift cams are simply rotated to a neutral point where the original shifters will function as normal. The computer shifts both derailleurs. The software knows when to shift which derailleur determined by the ratios between the sprockets. Control for shifting is just two buttons, one for up shift and one for downshift. I have two tiny buttons mounted on my right index finger glove so I can shift gears wherever my hand is located. This includes pressing the buttons agent anything on the bike or by my thumb. A single beep from the computer warns of an impending front derailleur shift and two beeps warn when both front and rear derailleurs are going to shift to maintain optimum selection of front and rear sprockets. This system can be programmed to properly shift any derailleur system no matter how many speeds or weird spacing. It can be fitted to any bike and removed with no evidence it was ever there.