Currently, one can find available on the market tons of single-chainring drivetrains, of which a lot rely on the 11-speed cassette, which all have another common feature – spicy price. It was just a matter of time until the one-ring trend took over the world and users started transforming their own multispeed drivetrains into single-chainring ones, but simultaneously rose the problem of how many sprockets do you really need and which size should that one chainring be? Should you inflict damage to your wallet by buying an 11-speed cassette, or go for the one with 10 sprockets and more affordable prices? Should you rely on the 32-tooth one or on the 30-tooth one, given that your lowest sprocket numbers 36 teeth?
With the aim of making you spend less than you would on a 1×11 drivetrain, Fouriers offers an at least interesting alterantive for single-chainring system fans that includes a 30-tooth chainring and a 42-tooth sprocket. As in the case of most products these days, compatibility issues narrow the array of situations where the kit can be used, but as far as costs go, Fouriers set is nothing short of a small miracle.
The chainring (CR-DX003-AH) and MageSK sprocket (CR-DX004) will set you back 145 euros and weigh 46, respectively 71 grams (for the sizes mentioned above), and the only option regards the chainring size, the number of teeth counting 32, 34, 36, 38 or 40, with the according weight penalty.
Now, compatibility isn’t really this set’s strong point, since you only have a handful of components that allow its mounting. The quite thick sprocket fits on 10-speed cassettes that belong to the Shimano SLX, XT or XTR groupsets, and in order to mount it, you’ll have to remove the 15-tooth and 17-tooth sprockets with the purpose of making some room for the 42-tooth beast. The manufacturer also delivers a 16-tooth sprocket with a custom, more narrow shape, that replaces the removed sprockets and spacer. This set is off limits to SRAM users because regardless of the removed cog, the Fouriers components push the cassette a few millimeters outside the freehub, making tightening impossible. As for cranksets, we finally used the chainring on a Shimano Deore 2014 one, after unsuccessfully attempting to make it work with a 2014 Shimano XT (uncompatible in terms of the bolts’ placement).
As for on-trail performance, the 30-42 gear ratio is more than enough to get you over steep climbs, but it will require a bit more effort than a 24-36 ratio. You will have to adjust the rear derailleur to the new position that the 42 sprocket implies, and no matter how fine you will tune it, shifting won’t be as accurate as before. Fouriers also delivers a longer adjusting screw for the derailleur in order to provide some extra length to the travel, but in our case, where we used a SRAM X0 derailleur, it turned out to be too short. However, it works just fine for any Shimano rear derailleur.
If climbing becomes easier with the new ratio, rolling over flat terrain will require serious involvement as the 30-11 highest gear doesn’t exactly favor reaching high speeds. Our take is that with a single-chainring system finding a compromise that suits both climbing and riding on flat terrain is a daunting task. So, the only viable option that remains is testing different combinations and picking the one that suits you best, according to the type of riding you plan to do and, naturally, your level of fitness.
The Fouriers chainring keeps the chain very stable thanks to its specially designed teeth, a feature which should be highly regarded, since you won’t have to use a chainguide, like in the case of a ring coming from a double or triple crankset. This also allows saving some precious weight.
Leaving aside the fact that the Fouriers chainring and sprocket work, at least for now, only with Shimano components (it’s true they get along with SRAM derailleurs, but reaching a decent functionality will need extra skill), this set allows you to convert your drivetrain in less than an hour. Working very well in all conditions, it also represents a cheaper alternative to 1×11 drivetrains, and in the same time one that should be regarded especially if you want to reduce the weight of your bike by about 400 grams.