Rohloff2368811000 Chain Wear, Grey, 8 x 3 x 3 cm

Campagnolo recommends to change the chain when the distance between 6 links is 132.6 mm this is a 0.6 mm stretch in 6 links.A chain should be replaced when it has been stretched more than 0.1mm per link and that is the suggestions by Campagnolo.This high quality tool interestingly uses also 6 links for the measurement and had 2 measurements, one at 0.1 mm stretch per link, marked as 0.1 mm an the other at 0.075 mm that Roholoff said should be use for alloy cogs. I use the 0.075, a chain is cheaper than cgos and chainrings.

Stretched chains can ruin your rear cassette teeth. This product is easy to use and has two scales/sides, one for chains being used with titanium cassette sprockets and one for all steel sprockets. Simple instructions. Recommended by Lennard Zinn.

There's a problem with this tool -- as well as its copycats by Park, Sette and others -- that consistently creates premature "worn out" indications on chains that are still good for use.The problem is a near and dear pet peeve of mine, and has been for a long time. It is difficult to describe using just words, as I've learned from previous discussions online, but I'll try: This style of wear indicator pushes two of the chain's rollers in opposite directions, so not only is it measuring chain elongation due to wear, it is also measuring the slop between a roller and the pin (where slop is always present, even on a new chain, but the amount of slop is inconsistent between brands & even models of chains).For a good graphical representation of the problems of this design of chain wear indicator, use your favorite search engine to look for "pardo chain wear measuring tools" (pardo,net being the host website, not a seller or maker of chain gauges).With this tool, I consistently received "no go" indications when the chain was just over half-way to the real wear limit.So far, the only wear tool I'm familiar with (but haven't owned) that measures correctly is the Shimano TL-CN41 Chain wear indicator. It uses three prongs, two of which push two chain rollers in the same direction (just as a cassette or chainring would) and checks the distance between them. With this approach, the tool is measuring only chain elongation, and roller slop is not a factor.(There's the presumption that roller slop is the same for each roller in the chain, but that assumption is just as relevant when the chain is brand new as when it is worn.)My own method is the "12 and 1/16th rule" and requires only an accurate steel ruler. The distance between two chain pins is exactly 1/2 inch on a new chain, or 12 inches when measuring across 24 links. Once 24 links measure out to 12-1/16", the chain should be replaced without risking damage to the cassette cogs and chainrings.The good news about the Rohloff Caliber, and others like it, is they'll never give a false "OK" condition. So from that standpoint, if you use this tool, your drivetrain will remain in great shape. But you'll be spending nearly 2x as much on replacement chains.It's regrettable I feel compelled to give this a one-star rating -- after all, I'm a huge fan of Rohloff and there's no doubt that the Caliber is a precisely engineered and manufactured instrument. But if it's measuring the wrong thing, all the rest is for naught.

This gauge cheap, quick, handy and fits in any tool box. A worn chain takes more energy to pedal. One side of the tool measures chain wear for alloy sprockets and the other side measures chain wear for steel sprockets. You can tell when a chain is starting to wear by using the side for alloy sprockets. The Shimano TL-CN41 gauge may be more accurate but is WAY too expensive. It is just as accurate but cheaper to measure a lightly loaded chain with a ruler. But measuring chains all day is tedious so bike shops assume that Rohloff has accounted for roller play in their design. Every bike shop uses this tool. If you want accuracy measure the chain with a ruler but if you want the industry standard this is the tool to buy.