I’ve never been so happy to wear out a chain in my life. None of us have. It’s weird, but as soon as you have to wear out a chain it becomes this thing that you have to do that just kind of hangs around like a chore. Oh, can’t ride that new bike, have to ride this one. Can’t go for a road ride, need miles on the mountain bike. Ok, ok, it wasn’t that bad – I mean we were riding bikes, which is awesome. We were also riding bicycles equipped with Shimano’s rad XT mountain bike drivetrains in both 9 and 10 speed variants, all in a scientific-as-possible-but-not-really-all-that-scientific test of which chain would last the longest. It was the most scientific test we could put together, and the relative uniformity of the results seems to validate our methods, somewhat.
What’s most important, is that our test results seem to back up everything Shimano claims – which is even more important as we toe the line into 11 speed (and even 12 speed?). Chains are getting narrower to accommodate more gears in a smaller space, but does that correlate into weaker as well?
See the results of the first, and possibly last BikeRumor Chainwear Challenge after the break.
As a refresher, we started the Chainwear Challenge almost 2 years ago and with the help of Shimano outfitted 6 test bikes with matching Shimano XT Drivetrains. Three bikes were equipped with 9 speed 11-34 cassettes and HG-93 chains, while the 10 speed bikes were given 11-36 XT cassettes and HG-94 chains. All bikes were also set up with new cranksets to ensure equal wear on the chainrings and new cables and housings across the board so shifting issues wouldn’t keep anyone from shifting. In hopes of keeping variables as low as possible, all bikes but one were Trek Fuel EX models.
Yes, I continue to make ridiculous faces when my wheels leave the ground – I’m working on it. Eduardo however, has it down. Also, Pearl Izumi’s new MTB kit is very blue, I know it’s not for everybody, but I like it.
Riders were told to ride as normal, while allowing me to install the parts, adjust, clean, and lubricate chains as needed with Dumonde Tech Original formula, and to stop by for chain measurements every 50-100 miles. When each chain was measured, it was measured in 4 different locations around each chain, and the highest measurement was taken – which turned out to be important as two of the chains had measurements a full tenth apart by the end of the test. Taking one of those lower measurements at face value would have skewed the test. Also, as we mentioned earlier in the testing, for an accurate chain measurement it is very important to clean and lubricate the chain first so that the dirt and contaminates inside the chain don’t affect the measurements. When you’re using a chain wear gauge that measure in 100ths of a millimeter, this is a very important step. Chains were considered to be worn out once they reached 0.8mm of stretch as specified by the Feedback Chain gauge.
As mentioned, the test got off to a bad start thanks to an insane amount of rain that rendered our local trails as useless as a broken derailleur hanger, which is why it has taken so long to complete. This season had much more favorable conditions with some epic riding and plenty of miles to go around.
If you have ever had the chance to listen to a Shimano Technical guru wax poetically about chains, chain construction, and chain wear, then our results probably won’t surprise you. Simply put, the 10 speed chains lasted longer. Quite a bit longer, in fact. Even the difference between the worst performing 10 speed chain and best performing 9 speed chain was still 225 miles. The difference between Bob and Chris (both endurance racers of similar skill and size) was a whopping 470 miles.
While the performance of the 9 speed group was fairly constant, the 10 speed chains seemed to gain a second wind in the last half of their total mileage. They just wouldn’t die – I would tell riders to expect only about 50 more miles, only to have them return 100 miles later and still not be finished.
Once all the chains were finished however, each rider installed a new chain on the used cassette and chainrings to test the level of wear, and the ability of Feedback Sport’s Digital Chain Wear Gauge to detect the point of chain wear where the cassette will still be ok to use. While we wouldn’t pass off the cassettes as new, there was no detectable skipping or shifting issues on the the cassettes with the new chains indicating that they had not been pushed too far. Because of that, Feedback’s gauge gets full marks as one of the most accurate chain gauges we’ve used.
During the entire test, there was only one malfunction if you want to call it that, which was Riley breaking his chain. I wouldn’t say it was the chain’s fault though, as it broke apart after being smashed between a rock and the big ring. We had to cut some links out on the trail to keep things rolling, so we decided to end its test there since we would have had to add links from a different chain to make it long enough which could alter the results. Riley was on pace to have the best score for the 9 speed group, but even then his numbers were no better than the worst 10 speed chain at the time. Riley is also only 125lbs, so he was the light weight of the group by far.
So how did they do it? We’ve spoken with Shimano many times about the durability of their chains, and what thinner chains mean for durability, and the answer is always the same – the new chains are stronger, because they are engineered to be. In fact, Shimano claims the new Dura Ace 11 speed chain is the strongest chain they’ve ever made which means it replaces the XTR Dynasys chain for that honor. In order to make this a reality the new chains are built with tighter manufacturing tolerances, improved plating, and improved design, all of which add up to better shifting, and better durability. Shimano is quick to point out that there is actually very little correlation between chain width and durability, if any. Rather, ultimate durability comes down to the construction of the chain and the layout of the gearing like the wide range of the cassette and narrower range of the crankset on the Dynasys drivetrains.
Does that mean an 11 speed Shimano MTB group is on the horizon? We have no idea, but we’re sure they could do it.