New Tech: absoluteBLACK Chainrings provide Compact and Sub-Compact gear options for Shimano Cranksets

absolute black sub-compact chainrings and weights

“absoluteBLACK is a cycling company devoted to extraordinary design, European manufacturing and production of parts that not only perform great, but also last a long time.”

“We believe anything out there can be made better, including chainrings.”

absolute black sub-compact chainrings and weights

absoluteBLACK Sub-Compact 48/32 and 46/30 Oval Chainrings

“As a manufacturer of chainrings, absoluteBLACK receives requests and questions on daily basis for unusual chainring combinations such as;  52/32, 50/30, or 53/32T, which are not going to work well due to component limitations (namely front derailleur), nor are good for keeping a good cadence across both rings and minimize shifting.”

absolute black sub-compact chainrings and weights

absoluteBLACK are launching a range of ‘Sub Compact’ oval chainrings in 48/32 and 46/30T that can be mounted to any 4-bolt Shimano crank, including models like Dura-Ace 9100, Ultegra 8000, Dura-Ace 9000, Ultegra 6800 and lower groups. It gives virtually anyone a chance to adapt one’s gearing to their abilities.”

absolute black sub-compact chainrings and weights

30 and 32T chainrings hugely improve the cadence and smoothness of pedal stroke while riding long/steep climbs, and therefore have significant, positive impact on overall performance. Additionally, 46 or 48T still allow for a high gear output on daily and group rides.” – Referring to road / pavement / bitumen-oriented rides.

“48 x 11T @90rpm gives 50km/h (31mph) and 46 x 11T results in 47.6km/h(29.6mph). Pedalling @100rpm it is 5km/h faster. At absoluteBLACK we believe It’s more than needed for a vast majority of riders who, like us, treat riding as pleasure and not as a job.”

Chainring Concept

“Configuration of ‘Sub Compact’ chainrings was considered impossible to manufacture on regular 110/4bcd crank spider, because 32 or 30T chainring teeth lay below mounting hole circumference. Therefore, these sizes were not available in the mainstream for years. However, thanks to absoluteBLACK patent pending “offset chainring” solution, it now becomes a reality.”

absolute black sub-compact chainrings and weights

“The small (inner) chainring was re-positioned closer to the frame by 2.5mm using small threaded tabs (a solution similar to the absoluteBLACK 30T 104bcd chainring). This allows the chain to freely clear the mounting tabs of the crank.”

absolute black sub-compact chainrings and weights

“To keep the same distance between chainrings, which is necessary for proper shifting, the big (outer) chainring was also moved by the same distance using special recesses around the mounting holes. All these offsets on both chainrings and the use of custom bolts make it possible and also allows for easy assembly of the chainrings.”

absolute black sub-compact chainrings and weights

absoluteBlack state their solution does not require any modifications to the rest of the drivetrain. Additionally, they claim an improved chainline for the gears that are used most frequently, which theoretically lengthens drivetrain life.

absolute black sub-compact chainrings and weights

“Both 30 and 32T chainrings have threaded mounting tabs. The 30T requires two special M5 Ti bolts and two M7 aluminium bolts, whilst the 32T is fixed with four M7 bolts. Both chainrings are fixed together with the bolts from the front, making it possible to mount them without removing the crankset from the bike.”

absolute black sub-compact chainrings and weights

Front Derailleur Setup

“48/32T chainrings require exactly same setup as regular compact chainrings. That is, a 1 – 1.5mm gap between tooth tip and derailleur cage. The only exception is the “L” bolt which has to be opened completely since chainrings are positioned closer to the frame.”

“46/30T is setup in almost the same way as the 48/32. However, as almost every frame manufacturer never predicted the use of a 46T chainring on road bikes, the front derailleur braze-on mount is generally positioned a little higher than is desirable. absoluteBLACK advises in this situation to set up the front derailleur as low as your braze-on allows. This should leave an approximate 5mm gap from the tooth tip to cage edge. 46T shifting ramps were specially designed to accommodate such a distance, thus front shifting remains crisp and quick.”

In the case of cyclocross and many gravel bikes, they were designed with smaller chainrings in mind, so the limitation with lowering the front derailleur may not apply.

Chain Limitations

Due to precise tolerances, clearances and special design of the chainrings, absoluteBLACK only recommends using Dura-Ace CN-9000 or Sram Eagle 12-speed chains. Both of these can be used in 10 or 11-speed drivetrains and result in quiet and precise running.”

“Chainrings are sold separately, but can only be used as combinations of 46/30 and 48/32T. No other chainring combination is possible due to specifics in the chainring’s design.”


46T / 48T chainrings are 105 / £95/ $US 124.00.

30T / 32T chainrings are €76 / £67 / $US 87.50. Small chainrings include the required bolts in their price.

absoluteBLACK Premium OVAL ROAD 2X chainrings for DA9100 & Ultegra 8000

Riders seeking bigger gearing options for their gravel or road bikes, absoluteBLACK has released a line of chainrings starting at 50T / 34T that cater to Shimano’s latest Dura-Ace 9100 and Ultegra 8000 road cranksets.

absolute black sub-compact chainrings and weights

“In addition to the Shimano’s 9100 / 8000 series of cranksets, our new OVAL ROAD design is also compatible with the previous generation Shimano Dura-Ace 9000 and Ultegra 6800 series cranks, which share the same 110mm BCD/4 arm specification.”

absolute black sub-compact chainrings and weights

The new Shimano 9100/8000 specification Premium OVAL ROAD outer chainrings continue to feature visually stunning and intricate CNC machining to carefully reduce their mass to a minimum, without sacrificing any performance or strength and an attractive, durable hard anodised finish.”

absolute black sub-compact chainrings and weights

The new Premium OVAL ROAD rings feature an updated and improved integrated ramp design. The new CNC machined ramp profile has proven, through heavy testing, to deliver even faster and more precise front gear shifting performance than before.”

Chainring Sizes and Colours

Premium ROAD OVAL outer rings are available in Black, Grey and Champagne, while the Premium OVAL ROAD inner rings are available in black only.

Inner OVAL ROAD rings: 34T (31g), 36T (37g), 38T (41g), 39T (42g).

Outer OVAL ROAD rings: 50T (120g), 52T (137g), 53T(139g).


Outer OVAL ROAD chainrings are €105 / £95/ $US 124.00.

Inner OVAL ROAD chainrings are €47.50 / £53.95 / $US 61.95.

absolute black sub-compact chainrings and weights

“Not completely necessary for full function, AbsoluteBLACK recommends fitting our additional CNC machined aluminium bolt covers to create the smooth ‘flush fit’ appearance between the Shimano 9100/8000 crank arms and our Premium OVAL ROAD rings. Our CNC machined bolt covers cost €47 / £41.50 / $US 52.00 and are available in either Black or Grey.”

“As ever, we recommend swapping both outer and inner chainrings to our Premium OVAL ROAD rings, though we also remind you that it is possible to combine either of our inner or outer ovals with your existing round rings.”

JOM’s Thoughts

Stating the obvious, ovalized chainrings are not for every gravel or road cyclist. If absoluteBLACK produced their innovative chainrings in a standard round design as well, I’m certain they would sell many more units. With that said, I did ride a competitor’s ovalized chainrings this past weekend (21st of January, 2018) during a 106 mile / 170 kilometre roadie oriented ride. As I pedaled along, I could tell no discernable difference from the round chainrings I’ve been using for well over 25 years of cycling. Your experience may differ.

The other thing I am curious about is chainring clearance. Shifting the inner chainring closer to the frame by 2.5mm may cause issues on some frames?

I expect to receive samples of absoluteBLACK’s sub-compact chainrings for review, soon. Watch this space!


13 comments on “New Tech: absoluteBLACK Chainrings provide Compact and Sub-Compact gear options for Shimano Cranksets

  1. I am running the direct mount Absolute Black 42T with Force 1 crankset on a custom Salsa Warbird frame up build I just did, with SRAM XX1 10-42 on the back. I love how it smooths out my cadence, especially on the tough, steep climbs where I want a higher, but smooth cadence. I love this oval ring.

    I’m now thinking about whether I want to go with them on my 52/36 road bike and my 42T single-speed.

  2. I too run the AB oval rings on my mountain bikes for several years. Basically you can run a higher tooth count by going oval, ie normally I would run a 30t (1X11) round ring, but I run a 32t oval for the hilly stuff I ride and I don’t feel any loss of power when the going gets slow.
    I’m wondering how well the 2X11 AB rings would shift on my gravel rig. Anyway, thanks Jayson for the informative and timely review. I am looking to “re-size” my std compact (50X34) ring setup.

    1. Don’t think of this as a review, but rather a press release / preview. I’m hoping to receive samples for evaluation.


  3. I guess that only an ovalized 30T or 32T inner chainring fits the bolt pattern, because the “asymmetric” bolts make it possible to reduce the radius in the sections in-line with the crank arms.

    A round 30T or 32T would probably have too small diameter at the bolts.

    1. Every ovalized chainring I have seen is still round on the inner to mate with crank’s fixing points. With the absoluteBLACKs, I don’t see there being any difference. What you are suggesting is the fixing points on the crank would need to be modified, which is not the case.

    2. Ben,

      You are correct. The stock mounting points would were unchanged and are only able to be used in such an application due to the asymmetric bolts!

      Our oval sub compact rings are the first available for any massively produced on the market that can use such gearing, everything else is either a mountain bike crank or a proprietary system.

      The fixing points on the crank are not changed, but where the bolt would normally go is offset in the chainring by using a smaller bolt.

      -Tony B (absoluteBLACK)

  4. I’d like to see these for SRAM and Campy, which are the drivetrains I use on my bikes.

  5. I’ve just been dealing with front derailleur fitting on a new build with a (round) 42t outer ring. On my Cannondale I could get a 105 derailleur low enough, but on my new Ti frame the bottom of the cage hits the chain stay before the FD is low enough. Turns out Shimano makes a non-series FD-CX70 with a shorter cage to solve this problem. It’s a short arm design so 9/10 speed (not 10sp Tiagra) pull.

    But I don’t think there is any way I have 2.5 mm between the FD mechanism and my large seat tube when at the standard location for the inner ring. But Phil Wood’s external bearing BSA BB comes with spacers that would allow you to fix this at the cost of non-centered pedals. Probably would work for any threaded BB (another win for threads!).

  6. Despite these chain rings being advertised for gravel they move the chain line 3mm inboard. If your gravel bike has wide spaced chainstays to accommodate wide tyres then the inner chain ring can foul the chain stay. If there rear OLD is 135mm then the cassette is moved 2.5mm outboard further deflecting the chainline and making small / small cross chaining impossible

  7. Well I just tried the 46/30 combo oval combination on my Santa Cruz Stigmata yesterday. Unfortunately moving the inner chainring inboard created a rubbing against the frame. Took me several attempts to realize this is not operator error, and after remounting the Ultegra 50/34 everything was back to normal. I really wanted these to work, waiting to hear back if there’s a solution from AB.

    1. David Bryant, did you get any advice or foud solution to your problem? I have same problem with my Wilier Jena – inner ring contacts to chainstay.

      1. Same frame clearance issue on my 2018 Salsa Warbird ? Thought I tightened the crankset pre-load a little too much. Turns out the inner ring was shaving off some clear coat from the BB area. Put the 50/34 Ultegra rings back on.

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