29inch:A Narrow/Wide Chainring Comparison Running SRAM XX1 on my fatty has shown that the componen
29inch: A Narrow/Wide Chainring Comparison Running SRAM XX1 on my fatty has shown that the component that wears out the fastest is the chainring. I went through two Wolftooth chainrings which had a lifespan of only about 600 kilometers each. That’s a very short distance that one could easily do in a single week on a regular bike. Fortunately, fat-bikes move through snow a lot more slowly and cover a lot less mileage. 600 weekend kilometers are about equal to half a winter. Two chainrings should get me through the whole winter. I wouldn’t put any fault on the Wolftooth ring, though. The chainring wear has a lot more to do with choices I’ve made, namely to use XX1 on a fat-bike in combination with short chain stays. Being a 1x11 drivetrain, there’s a lot of cross-chaining going on, no matter how you design a frame. As long as everything remains within the design parameters of the groupset, one should be able to get a descent lifespan out of the drivetrain components. Now personally I don’t know what SRAM recommends as far as ideal chain stay length and chainline. But as you reduce the length of a chain stay, the angle at which the chain has to run increases. Add to that the wide rear tire moving closer to the bottom bracket, you have to keep the chainring at a minimal chainline in order to have enough room for the chainstay to get through with enough clearance for a 4 inch tire. Since the chainring is the one piece I need to replace frequently, I’m testing everything that’s out there. I’ve started with Wolftooth as they were the first company to offer XX1 style chainrings for regular cranksets. Next in line in a couple of weeks will be a 32T ring by AbsoluteBlack. Once that one’s worn, I’ll be giving e*13 guiderings a try. I have two of them already. Who knows, maybe a different design and a different aluminum alloy might last longer than 600 km. Just getting 800-1000 km out of a ring would be a huge improvement. A brief out-of-the-box comparison: Both AbsoluteBlack and e*thirteen are nicely machined rings. The deburring on the AbsoluteBlack is a little sloppy as it seems to have been done by hand with a triangular scraper. That’s just a minor visual thing that won’t affect the function of the chainring. The e*13 guidering on the other hand is a perfect beauty with a topnotch finish. If you take a look at the above photos, you’ll quickly notice differences in how both companies designed the shape of the teeth. AbsoluteBlack uses a wider asymmetric tooth profile that reminds me a little bit of a sawtooth. On each side of the ring, they milled out a small undercut at the bottom of the teeth. I’m not quite sure what the purpose of this undercut may be, possibly it has a bit of a self-cleaning effect. Gunk may not accumulate as easily with such a design. e*thirteen opted to have narrower teeth and wider openings that seat the chain. Each side of the narrow teeth have two angled chamfers rather than the usual one. A nice feature is that you can change your chainline by 1 mm simply by flipping the chainring. Mount it one way and the chain sits further out or flip it around and your chain will be a millimeter closer to the chain stay. I’ll report back once I wear through a set of each ring, so stay tuned for an update in a couple of months to come. -- source link