Tip of the Week, 2016, number 1
If your answer to the following question below is “I don’t know” or “I don’t recall” the advice is: You probably need to change your chain!
The question is: When did you last replace your chain?!
So when do we replace our chains? Several seasons ago I sent out a general survey to our local ride groups asking the general question: “When do you replace your chain?” We had an interesting and generally thoughtful array of responses. The general consensus is that we should probably all be changing our chains more frequently than we do. Riders reported that they changed as frequently as 1,500 miles to 3,000 miles with many taking a quantitative approach to changing the chain. The final suggestion is that it is ideal to check the chain with a chain checker which is a simple device (several on the market) such as the slide tool from Park which for a 10 speed chain it is time to replace the chain when it measures out at 0.75. A new 10 speed chain will measure about 0.50. For an 11 speed chain the scale is moved down I understand to 0.50 as the time to replace it. One can physically measure the chain in lieu of using a chain tool but I’ll keep this discussion simple.
So why change a chain frequently? It is often put forth that replacing a bike chain is analagous to changing the oil in a car and the reason is to prevent undue wear and tear from frictional forces on the engine or in this case the other parts of the drivetrain from wearing out prematurely, specifically the rear cassette and the chain rings up front.
It is really quite remarkable to me even after all these years that a metal chain elongates to the extent that it does but they do! So what contributes to chain wear? Well, riding hills puts more frictional stress on a chain especially if you push a hard gear or “mash” on the pedals. Larger riders compared to petite riders should in particular stay on top of checking their chain. Spinning easier gears will generally get you more miles per chain. A clean drivetrain will perform better and wear less as well. Clean your chain frequently especially if after a rain day or a dusty route and lubricate the chain frequently as well. Experienced riders will suggest at least once a week. Riders who sprint will push a chain causing it to stretch as well. Even single speed riders need to check their chain frequently, perhaps even more than on a standard road bike, because the single speed set-up puts wear on the bike since there is only a “hard gear” when climbing.
The term chain-stretch is actually a misnomer. What happens is that wear occurs in each bearing/pin of the chain from friction caused mostly by dirt and grit. As the chain gets dirty it acts as sandpaper would and causes wear on each link of the chain. Multiply that wear by the average number of links of about 110 and the result is a chain that gets longer. In effect chain-stretch means the distance between the links have gotten longer which contributes to wear on your cassette and chain rings as well. The metal does not stretch but the bearing holes elongate.
So why bother changing a chain frequently? Just check out the prices of chain rings and cassettes. While a Dura-ace chain may cost $45.00 a Dura-ace cassette may cost over $200.00. If you stay on top of replacing your chain you will go many thousands of miles further without replacing the cassette or rings. When you replace your chain you will be amazed how it makes your bike ride smoother and easier. If you don’t change the chain frequently you will incur undue wear particularly on the rings of the cassette you find yourself in most frequently, in my case the 14 or 15 tooth gears. When it wears out you may get a skip and the trick it to replace the chain so that when you do there is no skip along the cassette or perhaps a drop from the big ring to the smaller ring when you are in a semi-crossover gear. [By this I mean, for example, the big ring in the front and a bigger easier gear in the rear.] We want to eliminate phantom shifts which are more likely to occur when the chain is worn and/or the gears of the cassette are worn as well. A phantom shift is when the gear changes without a concerted effort. It can be disconcerting, even risky, especially if in a climb or in a race scenario.
Special thanks to Philip Huyghe for his significant contributions to this article