absoluteBLACK Premium Shimano 110/4 bcd compatible oval chainrings are designed for new type of Shimano cranks Dura-Ace 9100 & Ultegra 8000 only. These are finest oval chainrings on the market in terms of shifting, smoothness of pedaling and manufacturing quality. (They can be also retrofitted to 9000 and 6800 cranks).
Size (Mass +/-1g):
34T (31g), 36T (37g), 38T (41g), 39T (42g), 50T (120g), 52T (137g), 53T(139g)
Compatibility:
Shimano Dura-Ace 9100, R9150 Di2 and Ultegra 8000, R8050 Di2. They can also retrofit 9000 and 6800 cranks but use bolt covers for best appearance.
Bolts:
For Outer chainring please order "Long bolts" from us OR Bolt Covers
Changing Inner chainring to oval only? use original bolts
Material & Finis:
CNC machined 7075 Txxx Aluminum. Long-lasting construction. Type II anodizing
Ovality:
Optimized to each size separately. 34T- 6.5% ; 36T, 38T, 39T- 11.4%, 50/52/53T - 10-11.2% ; Timing of 108 -110.5° after TDC (top dead center) - Ideal for road climbing. Patent Pending
IMPORTANT
Ramps on big rings are specially configured for combinations: 50/34, 52/36, 52/38, 53/39T
If you wish to use other configuration it will also work, but shifting will be slower and may require more "adjustments" of front dérailleur to be acceptable. Also remember that front dérailleur can only accept max 16T difference between 2 chainrings - this is how Shimano and Sram designed them.
Advantages of Absolute Black Road Oval chainrings:
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One of a kind special oval shape that helps you climb easier and faster (Patent Pending)
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Over 15% stiffer than Rotor Qrings due to thicker, 5mm construction
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Bespoke Absolute Black 6 point ramp and recess shifting design shifts better than any other brand and model of oval chainring
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Finest design that provides excellent strength to weight ratio
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You will not "feel" the oval shape while pedaling
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Your pedaling action will feel smoother
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Helps reduce stress on knees and helping your legs remain fresher for longer
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You will be able to maintain better cadence while climbing
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Reduces possibility of leg cramps
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You will reduce chainring/cog shifts by at least 15%
What size should I choose?
34T inner chainring should be used with 50T outer ring. It has 6.5% ovality. Use a 34T to help with spinning higher cadence and hilly terrain.
36T inner chainring can be used with 50 or 52T outer ring. It has 11.4% ovality. Use a 36T if you’re a strong rider or for rolling terrain.
38T inner chainring should be used with 52T outer ring. It has 11.4% ovality. Use a 38T if you’re a very strong rider or for flat terrain.
39T inner chainring should be used with 53T outer ring. It has 11% ovality. Use a 39T if you’re a very strong rider or for flat terrain.
50T outer chainring – Choose this size if you ride for pleasure or sportive events. This is the most versatile and comfortable size.
52T outer chainring - if you race and feel strong, it's the classic outer chainring size and a great option for experienced riders.
53T outer chainring - if you race and feel very strong, it's the classic outer chainring size and a great option for powerful riders.
Remember when selecting your chainring sizes - it's not about what others use, but about ensuring YOUR ability to maintain a comfortable and effective cadence across the terrain you ride most often. If you ride chainrings that are too large (round or oval), your cadence will be lower. This can affect your performance by prematurely tiring your legs and possibly lead to stress injury in your knee joints.
Shifting quality and technology
Both, inner and outer oval chainrings are optimized with smooth shifting in mind. This is why the back of the Absolute Black Oval road chainring does not feature cutouts, like other oval products on the market. Instead, we design smooth angled surfaces, to help chain to slide quickly and precisely between chainrings. Absolute Black outer oval chainrings have 6 up-shifting ramps, for easy and quick gear change, even under load. Each outer chainring also features 12 down-shifting points. Instead of steel shifting pins we use a CNC machined "ramp and recess" solution. Special raised ramps work in conjunction with the tooth recesses to stabilize the chain when shifting. Our oval chainrings DO NOT require any modification to the front dérailleur in order to work properly (apart from small standard adjustment)
Why our oval chainrings work
Our premium Oval chainrings work because riders do not produce power evenly through a pedal stroke –the musculature of human legs makes it difficult to maintain an even power delivery to a round chainring. Believe it (or not), but a round chainring doesn't transfer torque to your rear wheel as smoothly as an Oval one. Oval rings work with the natural human physiology. Oval chainrings maximize the part of the stroke where power is produced and minimize resistance where it isn't. As a direct consequence, Oval rings enhance a cyclist’s ability to spin with a smoother power delivery and feel easier on legs while climbing. You will actually feel your pedal stroke to be more "round" with an Oval chainring than with a round chainring.
Why using AbsoluteBlack oval chainrings matters
Absolute Black oval road chainrings deliver power more smoothly to your rear wheel. This means you are better able to generate and maintain, constant cadence. Because oval chainrings reduce the peak loads on knee joints, riders using them get less stress on the joints (knees) and therefore are able to keep certain level of effort for longer. This results in higher average speed. You don’t need to take our word at Absolute Black; 11 scientific studies by leading universities around the globe show that; in comparison to round chainrings, when using oval chainrings, human legs utilize more muscle groups - but each of them to lesser degree. The overall Load from pedalling an oval chainring is spread over greater muscle mass. This has three key benefits; firstly, it gives you the feeling of fresher and more relaxed legs. Secondly; it allows you to achieve higher average speed riding uphill. Thirdly; spreading the pedalling load over more muscles reduces the risk of cramp, even when riding hard. The compound effect of switching to oval chainrings; the relaxed legs, added climbing ability and reduction of cramp means your overall enjoyment of the ride is enhanced.
Why our Oval chainrings do not have adjustable timing
At Absolute Black we have extensively studied the relevant performance data regarding the optimum percentage of ovality, shape and, critically, the timing of the oval – the positioning of the high and low points of the oval, in relation to the position of the crank arm and focus this into one single mounting position – this is the really important part of what makes Absolute Black Oval chainrings so effective. By simplifying our oval chainring design, to reflect a single high performance ‘sweet-spot’, we are able to make the process of fitting Absolute Black oval chainrings faster and easier, as well as making our rings even lighter.