In case you haven’t noticed, there’s a massive buzz around running a one-by chainring setup in cyclocross. First of all, though, what is it? Well, unlike road bikes that have two chainrings, a one-by setup only uses one. Not to difficult to grasp. This single-ring setup is used with a chain guide that virtually eliminates the possibility of a dropped chain. There are a few reasons people like running this setup. The first is that it’s simple and foolproof. And if you haven’t tried cyclocross, you can start to act like quite a fool after you’ve been racing at your maximum for 40 minutes with the taste of blood in your mouth. Half way into a race, you’re much more likely to make mistakes, and few things are more aggravating than a dropped chain after you’ve been racing head-to-head with the same guy for the last half hour. Secondly, when the conditions get really bad, you don’t have a front derailleur, which can act as just another moving part that stops working on you. Another difference from road riding is that ‘cross doesn’t see the difference in speed like road racers do, so the large difference in gearing is therefore not necessary. One last thing is that a one-by setup comes with a lighter weight, because you’re able to eliminate more parts from your bike.
There are a couple options to convert you current double-chainring to a one-by setup. The original way to do so is with a chainring guard on the outside and a chain watcher on the inside. Or, you can also have a chainring guard on each side of your single chainring. More recently, though, people have been using mountain-style chain guides like the e.thirteen XCX, which are proving to be the preferred way to make a one-by setup, due to their effectiveness and simplicity.
One very large advancement in the one-by setup evolution is the technology that SRAM has just released with its XX1 mountain bike groupset. This system features only one chainring and no chain guide. This is possible with the Type 2 clutch rear derailleur, which keeps even tension on the chain over even the massive bumps. Shimano also has this rear derailleur technology for mountain bikes in its new Shadow Plus offerings. Sadly, though, this isn’t available specifically for cyclocross applications quite yet, but it is just around the corner.
So, whether you’re out to shed a few grams, or you just want to try something new, a one-by setup will prove worthy of your interests. Give it a go, and if you don’t love it, you gained an inexpensive lesson that solidifies your preference for the basics.
Read more tips by Jamey Driscoll
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