You can’t put a square peg in a round hole, but you can put oval chainrings on a bike. It’s a topic of great debate, but there are enough believers out there for companies like Italy’s Aribike to produce complete lines of oval (and round) chain rings for road, cyclocross and MTB applications.
Aribike offers a particularly wide selection of aftermarket chain rings, including rear adapter cogs and replacement cogs in non-stock sizes. After participating in a bio-mechanical study, their engineers finalized a shape for two complimentary styles of oval rings that they believe will provide the best training benefits, and now they have round or oval, single and double ring kits for Shimano’s 2015 XTR M9000 cranks…
Aribike’s oval rings are sold in two different styles that are designed to work together as a training system. The STRONG option is meant for training rides, and the RACE option for competition days. The crucial difference between the two isn’t about durability or weight, but rather lies in the position of the oval in relation to the crank arm.
The Strong rings are designed to force the use of muscles not normally active during typical pedalling on round rings, which Aribike claims will result in an increase of leg power and muscle resistance. The Race rings are designed to give you an edge on competition day. They force fewer leg muscles into action, thus saving you energy and theoretically producing the same result for less work. The company suggests setting up your training bike with the Strong rings and your competition bike with the Race set. With the Strong training rings Ari recommends the same crank length and tooth count as your current setup, but say riders will want one extra tooth on their Race rings.
Oval chain rings require some getting used to, but Aribike claims any odd sensation disappears after a few rides and benefits are evident after a few hundred kilometers. Riders should expect some initial muscle soreness as new muscles are being engaged, and they suggest shortening your first few training rides and not forcing your pedalling rhythm while you adapt.
There isn’t too much to say about the round rings. Aside from having a choice of Ari’s own high-tooth profile or SYNC ARI narrow-wide teeth they are otherwise just an aftermarket option with the same functionality as traditional chain rings. All chainrings are machined from Ergal 7075 T6 aluminum, and for an idea of weights the round 30 tooth monoring comes in at 38g and a 34 tooth oval ring weighs 46g. They’re available in a wide range of colors
Aribike’s Single-ring Kits are compatible with Shimano’s XTR M9000 BCD 96 crankset, and the rings mount with Shimano’s existing screws. The single rings work with 9, 10 or 11-speed cassettes.
The Round Mono-ring Kit includes one chain ring, available with SYNC ARI narrow-wide teeth in 30/32/34/36/38/40 tooth options, or with Ari’s high-tooth shape in 31/33/35/37/39. The retail price is $53 USD. The Oval Mono-ring Kit includes one ring with SYNC ARI narrow-wide teeth in 32/34/36/38/40 or with their high-tooth shape in 33/35/37/39. The oval single rings sell for $65.
The Double ring kits are compatible with XTR M9000 BCD 96/64 cranksets. While the double rings are designed specifically for 11 speed rear cassettes, they will also work with 9 or 10 speed setups. Again these rings are attached using the original Shimano bolts.
Aribike’s Round Double Kit includes two rings with the tooth count of your choice from the following options: Big rings come in single-tooth increments between 30- 42 teeth, and the small rings range from 21-30 teeth. Retail price is $90. The Oval Double Kit includes two rings, with slightly different tooth options: They still offer one-tooth increments, but don’t go quite as small with big rings available from 32-42 teeth and the small rings from 23-30. This kit sells for $102.
Please note the prices quoted above do not include shipping to the USA. To order, email email@example.com or visit their website.