I believe this is a reasonably decent calibration chart as I hit 0.5% or 0.75% on the chart, the other Park Tool CC-3.2 pass/fail gauge nicely slides in at the 0.5% and 0.75% sides respectively. The conversion table is of course not perfect as some chains came with an initial stretch measurement less than 0% (i.e., the CC-2 gauge would not fit in place). As such, 0% does not represent true zero. That said, we are really interested in the 0.5% or 0.75% wear, which the chart seems to approximate well (for how Park Tools measures chain wear).

You should always keep proof of postage and we advise you to use a ‘signed for service’ when returning goods. This change of mind return policy is in addition to, and does not affect your rights under the Australian Consumer Law including any rights you may have in respect of faulty items.Your high CC-2 reading likely relates to how much pressure are applying. The CC-2 device is not particularly solid and its readings are sensitive to how much pressure you apply to the pivoting gauge. This shop declares the total paid for the goods for customs value, no exceptions. We will not declare low values as thats fraud and we will not be party to it. Please enclose all your details and a covering note explaining the fault and any other useful details. There are two ways to go about buying the Park Tools you’ll need. The first is to get the equipment already bundled, like our home mechanic starter kit, and the second is to piece the right items together as you need them. Because you are also attempting to use Vernier calipers to estimate chain wear I thought I would share a method I derived for using Vernier calipers. I decided to follow the same method as the Park tools (inner measurement - your L1 approach - for 10 links) as I wanted to include wear on the bushings (as this is what the cog interacts with). As many have pointed out there is no perfect way to measure chain elongation.

Finance is subject to application, financial circumstances and borrowing history. Performance Cycling Limited FRN: 720557 trading as Tredz are authorised and regulated by the Financial Conduct Authority. We are a credit broker not a lender – credit is subject to status and affordability and is provided by Mitsubishi HC Capital UK PLC. Terms & Conditions Apply. If the items we have sent you are faulty, damaged or not as we described, we will cover the cost of collection and the delivery of the correct item. It is scary how bad the Tiagra chain is, out of the box it's stretch measurement is nearly 0.5% and I would be surprised if I get 40 hours of riding out of it (less than a month commuting) if I wait to 0.75% before I change.

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I repeated three measurements of the CC-2 gauge at the 0%, 0.25%, 0.5%, 0.75% and 1% gauge readings. I then took the average and did a simple linear regression against the gauge readings (below). As you can see your measurement of 120mm suggests 0.4% stretch. Typically I will measure the chain with Vernier calipers in three random places and take an average, then compare against the chart. I also record these measurements and regress them against the current distance or duration to get a better estimate of the current wear rate, as well as projecting service intervals. Predicting Service Life don't mention variable elongation vs replacement in the same way. But the CC4 is a better design which measures pin wear only.

Our experts recommend certain products for every rider, including stands. Your bike addict options in this category include event, portable repair, and wheel truing stands. And we’ve got shop aprons, bar style shop stools, and mechanic gloves along with coffee mugs when you’re ready to take a break! Most riders will be able to change the chain at a (real) wear of 0.5% but I have seen some where they can do so at nearly 1% wear, without skipping.I also have moved to measuring chain stretch via Vernier calipers, however my approach differs from yours as I try to mimic the cc-2 type inner measurement but with more precision (see below for methods). According to my calibration chart your L1 measurement suggests a chain stretch of 0.4%, which seems like a lot for 600 km, but not impossible. I would try repeating your L1 measurement a couple more times to be sure. Either way, you will likely need to change your chain soon. Using Vernier Calipers To Measure Chain Stretch

Faulty items should be returned within a reasonable time and in a clean and dry condition. PLEASE NOTE, WE WILL NOT PROCESS DIRTY ITEMS. a) If we have sent you the incorrect bicycle, we will cover the cost of collection and delivery of the correct model. If you find an item at a lower price with another commercial internet retailer, you will receive it from us at the same price, provided the conditions listed in the link are met. A better quality chain tool can help, or using calipers/a ruler as you are using. See this article from Zinn, for example -- essentially, you need to get an idea of the errors your tool makes, and you can be conservative with the replacement requirements (analogous to oil change intervals for cars; this can be a bit wasteful). Or, get a more accurate measurement (analogous to oil life meters in newer cars). It looks like he uses the Progold or Rohloff tools, which are inaccurate, but by getting an idea of the errors it makes, you can make a rough guess if you need to look closer for measurement, or just say screw it and replace the chain (even if its early) I settled on your inner measurement approach (pictured above) and calibrate my Vernier calipers against a CC-2 device, so I could translate a linear measurement into an approximate % wear. I did this by creating a calibration regression chart converting the Vernier L1 measurement to a stretch percentage (see below). I figured that while the CC-2 can be difficult to use consistently, it should at least be generally accurate. Note that my calibration measurements involved only a very light push on the CC-2 gauge. CalibrationSo I happen to be interested in an exact number for chain wear, but it arguably isn't so relevant for any given rider; whether the measurement includes roller wear or not doesn't really matter, because the exact chain wear won't tell them if they can fit a new chain or not anyway. The point which you have definitely left it too late depend on many things, not just the exact pin wear in the chain. Perfectly uniform wear (to the nth degree) is not that likely, but if the chain is wearing unevenly to a noticeable extent, this may be a clue that it isn't just ordinary wear that is the culprit; it may mean that the chain is corroding as well. If you wish to return your bike to us please keep it in the box it arrived in and call us on 01772 644340 and we will arrange a collection. For hygiene reasons, any intimate garments such as facemasks, underwear and swimsuits can only be returned if the items are faulty.