OVAL Raceface dm boost148 (3mm offset)Our premium 1X RaceFace Boost 148 direct mount compatible Oval chainrings are designed for CINCH system RaceFace uses to mount chainring directly to the crank. This version is for BOOST 148 specific bikes and FAT BIKES (when reversed).Size (Mass +/-1g):26T (52g), 28T (54g), 30T (58g), 32T (62g), 34T (69g), 36T (coming)ColorBlack, Cannondale Green, Red, GoldCompatibilityRaceFace Cinch system cranks. RF Next SL, RF SIXC, RF Turbine, RF Atlas, AEFFECT CINCH cranks. 9, 10, 11 and 12spd Eagle compatible.Materialcnc machined 7075 Txxx Aluminum. Long-lasting constructionFinishtype II anodizingChainline52mm. 3mm offsetOvalityOptimized to each size separately. Range: 10.2-14.4% and Timing of 110.5-116.3° after TDC (top dead center) Patent PendingDifference between Boost148 and non-boost chainrings is in the offset/dish of the chainring itself only. You would use same crank in both boost and non-boost bikes, but chainring offset has to be different to accommodate chainstay clearance. Boost chainrings have only 3mm offset while non-boost ones 6mm. Advantages of our special Direct mount chainrings: *We mastered our oval chainrings to perfection, so you can get best possible advantage from the oval/elliptical shape. *Finest design to provide excellent weight to strength ratio *One of a kind special oval shape (Patent Pending) *Greatly improves traction and climbing abilities *Unique Patent Pending narrow-wide teeth profiles to keep your chain in place for minimum 12 months! *Special 3D teeth machining for ultimate mud relief decrease wear and noise dramatically *They save weight because they don't need the spider and chainring bolts. *The ability of installation of a smaller ring sizes that can't be mounted on regular spider. *Superb quality and great look. *You will ride faster using ovals. If you keep using round ring then others will get quicker. *You will not "feel" the oval shape at all *Reduces stress on knees *Chainring is reversible and fits also Fatbikes with 170/190mm axlesWhy our RF oval chainrings work Our Oval chainrings work because a rider does not produce power evenly through a pedal stroke; they maximize the part of the stroke where power is produced and minimize resistance where it isn't. Oval rings make the spin cycle a lot smoother and are easier on legs while climbing. Believe it (or not), but a round chainring doesn't transfer torque to your rear wheel as smoothly as an Oval one. You will actually feel your stroke to be more "round" with an Oval shape than with a round chainring.Why it matters Traction, Traction and Traction. With oval rings rear tire traction improves greatly on loose and slippery terrain. Smoother power delivery to your rear wheel means that you will be able to maintain better, constant cadence; get less stress on the joints (knees) and therefore be able to keep certain level of effort for longer. This results in higher average speed. Moreover, 11 studies made by various Universities in the World show that using oval chainrings human legs utilize more muscle groups (compared to round one), but each of them to lesser degree. Load from pedaling an oval chainring is spread over greater muscle mass which in effect gives you the feeling of fresher and more relaxed legs. It is world's finest RaceFace cinch oval chainring backed by tens of thousands of customers.What size should I choose? * 26T Oval chainring has the ovality of 24/28T and is best for someone who uses currently 26T round ring. (Fatbikes!)* 28T Oval chainring has an ovality of 26/30T and is best for someone who uses currently 27 or 28T round ring. (Fatbikes!)* 30T Oval chainring has the ovality of 28/32T and is best for someone who uses currently 29 or 30T round ring.* 32T oval ring will suit best someone who uses 31 or 32T chainring currently. While pedaling, you will feel quite similar effort to the one riding round 31T ring (as the smallest diameter of the oval is 30T), but you will gain the speed similar to riding 33/34T chainring.* 34T Oval chainring has an ovality of 32/36T and is best for someone who uses currently 33 or 34T round ring.* 36T Oval chainring has an ovality of 34/38T and is best for someone who uses currently 35 or 36T round ring.How to mount RaceFace Cinch Oval chainring: The chainring has a mark on the backside that you need to line up with the center of the crank arm to achieve the main/recommended position. Once this is done use BB key to lock the lockring. If you wish to try more aggressive setup, rotate the chainring from main position clockwise by one notch on the splines. This will rotate oval by further 22deg. We do Not recommend second position for beginners. Before you start experimenting with the clocking of the ring, make sure you ridden minimum 5 months in the main position first.How to mount RaceFace Cinch Oval chainring on FAT BIKE: On Fat Bikes using 26 or 28T chainrings, it is necessary to reverse the chainring dish. 26 and 28T chainring has a double-dimple mark on the front that you need to line up with the center of the crank arm to achieve proper position. All other steps are same to the instruction above.Optimum Chainring Adjustment (OCA) - Our main/recommended clocking position is a fantastic setup for everyone. However some more seasoned riders may like a bit more aggressive clocking position. RaceFace oval chainring allows you to change clocking position by 22deg both ways from initial setup. This is the only chainring in our line offering this adjustability.It is ideal for 1x 9/10/11/12 system and Singlespeeds!. Oval (elliptical) chainring does not compromise the work of clutch mechanism in rear derailleur(video at the bottom). It also does not require chain tensioner when using in Singlespeed application. It is the most advanced oval chainring currently on the market.The most advanced, Patent Pending narrow/wide tooth profile on the Market guarantee minimum 12 months of excellent chain retention capabilities! We mean it. Always use a new chain with a new chainring.Chain options10, 11 or 12spd chain for geared bike or 6-9 spd for SS. If used in 1x9 drivetrain - 10spd chain must be used to obtain the performance. (yes - 10spd chain will work great on 9spd cassette)Chainguide needed?No. But if you want one then chain guide should have 2 teeth more capacity than nominal oval ring size.Designed in UK. Manufactured in Poland (EU).If you wish to check for frame clearance with new oval ring, below you can find measurement of biggest dimension of the oval (tip to tip of tooth):26T: 118mm ; 28T: 127mm ; 30T: 134mm ; 32T: 143mm ; 34T: 151mmWord on BIOPACE - Please understand that this is not Biopace technology. Shimano created Biopace with the completely wrong orientation of the biggest radius of the oval. Instead of positioning it in power zone which is slightly below the level of the crank, they clocked it to the dead zone where human generates least power. The result was that in power zone pedaling was too easy and in dead zone very difficult. Exactly opposite to how it should be.Other elliptical chainrings on the marketClocking (timing) and shape of the oval are the most crucial parts of the design. Ride quality of Absoluteblack Oval ring will be different to ovals from brand X or Y. 2 years of development of our ovals resulted in commercially most successful product of its kind. AbsoluteBlack is the First company who managed to successfully popularize ovals in mountainbike sport.Other manufacturers offer one timing and ovality setting for all chainring sizes, but pedaling behavior changes with each size considerably. To optimize for this, every chainring size needs to be slightly different. For example the smaller the chainring size the bigger the ovality has to be to help climb steeper hills more effectively. This is where we specialize in and optimize every size to particular pedaling style. This is also why we do not provide exact figures about timing and ovality of the chainring as each one is special and we need to protect our Patent Pending solutions. Due to our Global popularity and success there are now more companies releasing "similar" products. But "similar" is not the same. Even very small change in parameters of the oval shape and timing gives entire different feeling and performance. We mastered our oval chainrings to perfection, so you can get best possible advantage from the oval/elliptical shape.absolute black chainring components on facebookUnique Patent Pending narrow-wide teeth profiles to keep your chain in place for minimum 12 months!RaceFace is trademark of RaceFace corporation...