Chain wear is quite natural – but how do you detect it? When should the chain be changed and what about the chainrings? All tips on the chain gauge you can read here.

The chain gauge is a simple tool to measure the wear of the bicycle chain. Chain wear is the most common cause of frustration on the bike: slipping gears, squeaking, and grinding as well as unnecessary wear on the teeth of the sprocket is the result of an old chain. In fact, the occasional bouncing of the bicycle chain is still the mildest symptom of chain wear. If the wear of the chain is allowed to progress too long, the deformed chain will also cause damage to the sprocket. And that becomes expensive. That’s why we explain how to stop chain wear, measure wear, check the bicycle chain, and how often you should change bicycle chains.

meaurig tool
The chain gauge is an important part of working on the bicycle chain.

Why A Chain Gauge Is Important

With a chain wear gauge or chain gauge, you can determine whether a chain is worn. In principle, any chain gauge is suitable for any chain.

With the chain gauge, you measure the elongation of the chain. The wear of the chain glider ensures that the links are no longer tight, but hang loosely together. The distance between the chain links increases. As a result, the shape of the chain no longer fits the shape of the sprocket, which is also damaged as a result of chain wear, if you do not notice the wear-in time. This means the teeth on the sprockets and chainrings wear out – and unlike a bicycle chain, these components cost significantly more money when they are (unnecessarily) worn out.

guage for chain
Shimano’s instructions for using their chain gauge, 1, 2, yes, no… you don’t understand the drawing? Good, neither do we. Here comes some more theory and a complete guide.

The chain gauge always has (at least) one pair of legs. One leg, which is also marked with a “1” on many chain gauges, is also the first to be attached to the chain. This leg is therefore used to attach the wear gauge to the chain. Then the end with the other leg (“2”) is attached to the chain. If this leg now falls between the individual chain links and the chain gauge lies flat on the chain, the chain is worn and you should replace the chain. However, if the leg sits firmly between the chain links and can not be pressed down so far, there is no wear.

In the case of the Shimano chain tool TL-CN42 (pictured above), the drawing means that you should not use a lot of pressure when pressing down. But it remains unclear what “a lot of pressure” means exactly. In principle, you could also say: this chain gauge from Shimano must not simply slip through when inserting the end with the “2”.

So with this simple chain gauge, a simple “yes/no” answer is given to the question of chain wear.

Chain Gauges Measuring Methods

However, when using chain gauges, it is important to remember that the actual elongation of the chain is being measured. And not the wear of the rollers inside the chain. Chain gauges can measure at two points: by pushing the rollers in opposite and the same direction.

Depending on which chain gauge you use, the result will be slightly less accurate. The chain gauges that press in the opposite direction (variant B) are less accurate. Since the wear of the rollers is included twice in the calculation. Chain gauges from Shimano, therefore, have two pins at the first attachment point, which allow the measurement according to variant A. In the photo of the Shimano chain gauge, you can see on the right side that the pin is split in two.

Chain Gauge With 0.75 And 1.0

However, some chain gauges have over two pairs of legs to measure the chain a little more precisely. Usually, one end of the chain gauge is marked “0.75” or “0.075” in that case and the other end is marked “1.0” or “0.1”. These two pairs of legs indicate different degrees of wear. When the 0.75 leg falls through the chain links, it means there is 0.075mm of elongation per chain link – which means 0.75mm of elongation over 10 chain links. If the 1.0 leg falls through the chain links, there is already an elongation of 1.0mm over 10 chain links (or more!).

However, one can find different statements about how to deal with this information. What one can say with certainty: So that the 1.0 end falls between the chain links, the wear must already be very advanced and you should then change the chain immediately in any case.

However, according to their own experience, many cyclists advise replacing the chain as soon as the 0.75 end falls through the chain links. Because already some cyclists came to the fact that they had to replace the sprocket set because of too strong wear, although they had measured the chain regularly with the chain gauge and “only” a lengthening of 0.75 existed. And the sprocket set is already considerably more expensive than the chain.

But they also say that only the 1.0 end is suitable for measuring the wear of a chain on steel sprockets. Here, wear of 0.75 is not yet sufficient to cause damage to the more robust sprocket set. However, we also advise here not to wait too long with the change of the chain.

Determine Wear Through Chainrings

Also on the sprockets and the chainring, you can see if already advanced wear is reached. So if the chain is already longer on it and the teeth on the leaves/sprockets are already very pointed, then it’s time for the change. And indeed, the chain and the sprocket set and the chainring must be changed in the same step! Old components are already matched to each other, so a worn chain on a new chainring or sprocket would lead much faster to new wear. So always replace all three components if the sprocket and chainring are already worn. If only the chain is worn, then it is enough to replace it. With timely replacement, the teeth hardly wear out and can survive many chain generations.

When a chainring or sprocket is worn, the teeth sharpen (in the picture, the teeth are still fine).

Wippermann Connex Chains

Now one says however that one can determine with certain chains (e.g. Wippermann chains) the wear with a usual chain gauge not so simply. With the Connex chains from Wippermann, for example, one would determine with a conventional chain gauge much too early supposed wear.

How can that be? After all, every chain must fit on every sprocket. Otherwise, you would also break your bike without wear.

It is now so that the individual diameter of the rollers of the chains from manufacturer to manufacturer is different. This is also called the roller diameter. And even on a new bike, the rollers are not completely tight, but always have some play. Even small differences in size increase this natural play significantly.

However, this play is not so bad – because when the chain is on the sprocket, all rollers are pressed in the same direction. The chain gauge, however, presses the rollers in different directions and thus falsifies the measurement result.

To measure a Connex chain, you can now either reach for Wippermann’s own chain check gauge or push the chain links in the same direction when measuring.

The Falsified Result With Chain Gauge

The brand-specific difference of bicycle chains always causes discussions about how precise the measurement with the chain gauge really is. Accordingly, you would always have to reach for the chain gauge of the same manufacturer as the chain on which you want to measure the wear. In addition, no exact statement about the degree of wear of the chain can be determined and in many cases, you only know that it is actually already too late and you should have changed the chain earlier.

In addition, it must be remembered that the rollers of the chain are also affected by wear and loss diameter over time. This has no influence on the elongation of the chain, but it leads to the fact that even with the specific chain gauge falsified measurement results are generated.

Therefore, many mechanics tend to use a caliper gauge, which can be used universally and provides more accurate results.

How To Measure A Bicycle Chain With A Caliper?

A craftsman’s caliper (or caliper gauge) – which is suitable for precise measurement of all sorts of things – is also suitable for measuring bicycle chains. Here we explain how to measure a bicycle chain with a caliper.

For an absolutely accurate result, do not measure – as you usually see/hear – by placing the upper inner measuring legs of the slider between the chain links like a chain gauge. Instead, you measure from the outside, center pin to center pin, as this ultimately indicates the wear/elongation of the chain.

One usually measures the distance from ten links. For a mounted chain on the top (the part of the chain that is under tension between the sprocket and the chainring and transmits the power).

The distance for a new chain – from pin center to pin center – is 127mm. From a distance of 128mm you should change the chain, but the sprockets are probably still undamaged. From a distance of 129mm, one can assume from the advanced degree of chain wear that the sprockets also have permanent damage. In the case of mild signs of wear, this manifests itself in the fact that a new bicycle chain will wear much faster on the sprocket. But it may also be that a new bicycle chain will not find a firm grip on the worn sprocket.

Overview Of Different Chain Gauges

When it comes to commercially available chain gauges, you have to keep in mind that you would actually always have to use the chain gauge of the respective manufacturer of the chain in order not to falsify the result. Ultimately, however, it is enough for most cyclists to determine whether the wear is present or not. The chain gauge is extremely easy to use and gives a clear answer to the question of wear within a moment. For those who want to be precise, we advise the use of a caliper gauge.

How Long Does A Bicycle Chain Last?

To answer this question, you can give at most some guidelines. Because there are many criteria that play a role in the wear of the bicycle chain.

First Factor: Wear

Probably the most important question is: How long do you wear out the bicycle chain? You yourself decide when “enough” is enough and when the bicycle chain is through.

You have to keep in mind that it is ultimately about the wear of the sprockets, as they are much more valuable than the actual chain. Long before the chain breaks, the chain will still leave damage to the sprockets. That’s why you should watch out for chain wear at the first sign of it! Regularly measure the wear of the chain and check the degree of wear. The wear of the chain does not mean the wear of the sprockets and so you should be able to prevent damage to the sprocket with a little caution.

In addition, whether one has sprockets made of steel. These hold out namely already somewhat more chain wear than sprockets made of aluminum or titanium.

Second Factor: Driving Behavior

But wear also plays a role in terms of handling. You damage the chain by pedaling too hard for too long. You can protect the chain by shifting to a lower gear and pedaling faster and more often. Especially when you are shifting to another gear, you should not put pressure on the pedals.

But also, if the front and rear gears are shifted unequally and the chain is therefore not straight, but crooked, increased wear of the chain occurs. These are things that you should actively pay attention to as a rider when riding! See also our article on the chain line.

Third Factor: Environment

Only in third place comes the influence of the environment. Because even if you ride a lot in the rain, you can effectively counteract the wear of the bicycle chain with care and driving behavior! And it’s a fact that a well-lubricated bicycle chain attracts dirt particles that accumulate thanks to lubrication. If you ride your bike a lot, you can’t avoid possibly dealing with the care of the chain. Because the dirt particles do not leave the chain by themselves.

How To Stop Chain Wear

The service life of the bicycle chain can be extended with active, regular care. Nothing causes more wear than dirt particles that cause constant friction between the chain and sprocket.

Superficial dirt, such as grains of sand and dirt, should be removed regularly with a brush. It is recommended to clean the chain with a brush after every ride where mud and dirt have been sprayed on the chain. Here you can find a great guide to cleaning the bike chain:

It is advisable to use a special chain cleaner – a detergent designed to remove all deposits on the chain. This also means that it attacks the oil film on the bike. This is necessary because it is impossible to prevent fine dirt particles from mixing with the lubricating film of the bike. A chain cleaner is usually also an effective means against rust on the bicycle chain.

After using a chain cleaner, you need to restore the lubricating film of the bike. Only a thick film of lubricant allows the chain to shift smoothly even in wet conditions. That’s why it’s recommended to regularly re-lubricate the chain – but especially after you’ve applied a chain cleaner.