It’s true that our MTB chainrings will work great with SRAM’s Eagle groupset. The reason why SRAM redesigned the teeth on their chainrings, giving them a ‘hook’ shape, is an attempt to extend the poor life and noise reduction of their chainrings, that are known for fast wear and noisiness. Thanks to higher quality materials, advanced manufacturing processes of our chainrings and excellent tooth shape design, there is no need for a different teeth shape in absoluteBLACK chainrings. We’ve done it right the first time. Also 12spd chain is almost no different to 11spd one. 12spd chain has minimally thinner plates and resulting from it dimensions, but such change does not have any negative effect on proper work with chainring. In fact, most chainrings on the market that are 11spd compatible will run with Eagle chain with no issue at all, regardless of what Sram advertising campaign says.
It took Absoluteblack over 3 years to develop oval chainrings to the point you see them now. It also took great effort to introduce them to the market because of bad reputation non-round chainrings had in general from Biopace era (mistake Shimano made in early 90's). But Absoluteblack chainrings quickly proved to live up to the hype. With such a great success, other companies like WT and Oneup started producing their own version within few months. However all our patent pending applications prevented these companies to directly mimic the excellent design we use. Therefore all these companies created shape that "look similar" but is lacking test & optimization process as it takes years to finish. At Absoluteblack we believe we have created the perfect shape of an oval chainring to back up our claims. Any change to this shape will compromise the benefits you can have. What Absoluteblack claim to deliver will not be accurate for other oval shaped chainrings on the market.
No you don't. All dérailleurs on the market work perfectly fine with an oval chainring. Movement of the dérailleur cage is minimal and well within natural range.
No, as long as the tooth profile of the chainring is correct for the chain that your drivetrain uses (HG+, Flat Top, 10 speed, 11 speed, etc.). We always recommend fitting a brand new chain with your new chainring, oval or round. If you are unsure which chainring tooth profile your drivetrain requires, please get in touch with our customer service
Exactly same way as for round chainring. You just need to use the nominal size in the calculation of an oval ring you have. That is, if you buy 32T oval you use for calculation 32T size. Reason for this is 32T oval chainring has same circumference as the 32T round. We optimize the shape but not circumference - it stays constant. Distance between each teeth always has to remain at 12.7mm to engage the chain properly. You can use any online calculator to get gear inches for an oval chainring.
Yes. Please navigate to the Dealers tab. Rotors - Not currently, but you can buy them directly. Please contact us.
Yes we do. Sending our products out to almost anywhere in the world is just as exciting for us as it is for you.
Customers from USA, Canada, Australia and other countries outside Europe, should choose option in US$ currency Customers from Europe should choose option in Euro currency Customers from UK should chose option in GBP currency Choosing appropriate option means that shipping cost and taxes are correct for you.
For all the orders we use DHL Express courier services. Signature is Required at delivery. In rare instances we may ask you to cover for the real cost of shipping if your address is located in so called "remote area" according to DHL. In such case we will inform you about this before sending the goods out.
Europe: 13.90eur
USA, Canada and Rest of the World: 17.99$
UK: 10.90£
We do not send the goods by National Post due to extremely long shipping times and lack of tracking.
Please check our return policy at "Returns" page under "May we help?".
absoluteBLACK warranties its products, when used under normal non-abusive conditions, to be free from defects in materials or workmanship for a period of 1 year from the original date of purchase. Any absoluteBLACK product that is found by absoluteBLACK to be defective in materials or workmanship will be repaired or replaced at the sole discretion of absoluteBLACK. (for HOLLOWcage please refer to the next question).
This warranty is expressly limited to the repair or replacement of a defective item, and said repair or replacement is the sole remedy of the warranty. This warranty extends from the date of purchase, is offered only to the original retail purchaser, and is not transferable. This warranty does not cover damage or failure resulting from accident, misuse, abuse, alteration, neglect, normal and reasonable wear & tear (chainrings are wear items), crash or impact, failure to perform routine maintenance as instructed, or use other than that for which the product was intended. It also does not cover fading or wearing of anodizing. In no event shall absoluteBLACK be liable for any loss inconvenience or damage, whether direct, incidental, consequential or otherwise resulting from breach of any express or implied warranty or condition of merchantability, fitness for a particular purpose, or otherwise with respect to this product except as set forth herein. Under no circumstance shall absoluteBLACK or its third party suppliers be liable for any direct, indirect, incidental, special, consequential or any other kind of damages. This written express warranty is in lieu of all other warranties, implied or expressed, and does not cover any representation or warranty made by dealers beyond the provisions of this warranty.
Warranty is offered for defects in materials and/or workmanship for 4 years for the bearings and 1 year for rest of the cage from the date of purchase. It is non-transferable and valid to the original purchaser of the product only. It does not cover normal wear and tear that will inevitably occur, nor damage due to crashes, lack of drivetrain maintenance, impacts or neglect. It also does not cover the contamination of the bearings caused by the conditions they've been used in (rain, mud etc). Warranty also doesn't cover improper installation and any damages resulting from it as well as any damages resulting from use for any other purpose than intended.

If absoluteBLACK finds the HOLLOWcage to be defective in materials and/or workmanship, we will repair it or replace it. The user of the HOLLOWcage is solely responsible for correct maintenance, regular checks and when needed, replacement of components.

All warranty claims will be reviewed individually.

Every claim is to be sent to our customer service department, with proof of purchase and pictures showing the defect/damage. If our customer service department will require more information, pictures, etc.., you will be notified via email. In a situation where the owner refuses to provide the information/materials requested by our customer service department, we will not be able to process the claim.

In case the product has to be examined inhouse by absoluteBLACK, it is the owner’s responsibility to cover the costs of shipping, which are non-refundable.
The main issue with steel/hybrid bearings is rust. Since we provide full ceramic bearings this problem does not exist and full ceramic bearings last several times longer than any steel/hybrid bearing. If they get contaminated to the point they become loud, a standard service is needed to restore them to original condition.

Any damage to the bearings or other components of the HOLLOWcage OSPW system resulting from improper service, are not covered by the warranty.

Service procedure:

Remove the jockey wheels from the HOLLOWcage assembly using the provided proprietary installation/removal tool

Once jockeys are separated from the cage, remove bearing shield. This can be achieved by carefully leveraging them out of the bearing (always leverage the inside circumference of the shield). We recommend using a surgical scalpel or a fine point dental pick. When the shield is removed the ball bearings and the bearing cage will be exposed.

Place the jockey wheels in a container with white spirit, so that they are completely covered and shake vigorously until all contamination is removed from the bearing.

Take the jockey wheels out of the container and let dry completely (minimum 3 hours)

Once bearings are thoroughly dry, you can apply GRAPHENlube by dripping ~5 drops onto the bearing balls, spinning the bearing after each drop to spread the lubricant. Leave to dry for min. 2 hours. You can also use a small amount of Shimano Premium Grease (two match heads is enough)

When the above steps are complete, the jockeys are ready to be re-installed into the HOLLOWcage assembly. You will not re-fit the bearing shield as the bearing does not required it. It has been factory fitted only to extend the initial service interval.

Place the jockeys in their designated upper (smaller jockey) and lower (bigger jockey) positions, remembering that the side with fully exposed bearing has to face away from the HOLLOWcage assembly (mono-plate). Torque the lockrings to the required torque value.

Your HOLLOWcage OSPW system is now ready to be used again.
EU customers will not have to pay any additional fees. However if your shipping destination is not included in EU duty free agreements e.g. Canary Islands, additional fees may apply (customs or IGI(vat) at the border).

In UK all parcels valued above 160 GBP (excluding shipping) will be liable for 20% VAT and about 9 GBP customs handling fee at the arrival. In order to avoid this we suggest splitting your shopping basket to below that value per order.

Worldwide customers usually will not have to pay- but we can’t guarantee that.

Known to us exceptions are: Canada, Brazil, Argentina, Chile, Peru, Colombia, Malaysia, Indonesia, Philippines, where you will have to pay duty and corresponding fees because those customs offices hold Every single parcel.
You can pay with PayPal or by using your credit / debit card. We also offer an option of a bank transfer.
Yes we do. If your absoluteBLACK product is damaged in a bicycle crash within a year from the date of purchase, absoluteBLACK proposes to replace it at a reduced price to the original owner.
If you have purchased one of our ovals directly from our website, and after 30 days of riding you don’t feel the difference in your pedal stroke, you can send it back to us for a round replacement (if available) or, if round replacement is not available, a refund. 30 Day Satisfaction Guarantee only applies to ovals purchased on our website and does not cover the mechanical aspect of the oval conversion (for example derailleur adjustment).
If you are unsure which size of an oval to get, when moving from your 2x drivetrain to a 1x (using our MTB oval) you should start from determining the size of a chainring that falls in between your current chainrings. For example, if you have a 2x drivetrain with 24T and 36T chainrings, size in between would be 30T, use that size as a “baseline”. If you don’t have preference in your current 2x setup, and spend equal time in each of the chainrings, oval in “baseline” size should be a good size for you. If you find yourself riding more in the smaller chainring, you should consider choosing smaller oval than the baseline. If you find yourself riding more in the big chainring, you should consider choosing bigger oval than the baseline.
At the moment we are unable to produce custom colours or one off sizes. We also don’t etch our chainrings.
The type of Oval Guide that is right for your bicycle, is determined by your bicycle’s frame and the mounts that it’s equipped with. If you have an ISCG05, HDM (High Direct Mount for front derailleur), S3/E-type mount (direct mount for front derailleur), you can use our Oval Guide. Oval guide is designed for MTB bikes (not for road). With Road bike you should use our “chain catcher”.
If you are unsure, you can always send us a web link to your bicycle/frame’s specification (with pictures), or alternatively you can send us a picture of you frame and the mounts that it has.
We always recommend swapping like for like, so if you have a 32T round ring at the moment, you should consider getting a 32T oval. The same applies to our shiftable road ovals, we recommend that you purchase ovals with the same teeth count as your round rings.
Yes, they will. We have a special version of Sram and RF direct mount rings with correct 3mm offset for Boost frames. So when purchasing please choose the chainring option “Boost 148”.
Yes, they will. Unlike Sram/RF direct mount chainrings that require different offset, chainrings for Shimano cranks are exactly the same for regular bike and Boost148 one because the necessary offset is in the Shimano crank itself (Shimano makes 2 crank versions: Boost and non-boost). So all you need to do is to choose your correct crank bcd from our website and don’t worry about the “Boost” specifics.
Long bolts: M8x0.75, 8.5mm long thread and 7mm high nut Short bolts: M8x0.75, 6.5mm long thread and 4mm high nut
In no event shall absoluteBLACK be liable for any loss inconvenience or damage, whether direct, incidental, consequential or otherwise resulting from breach of any express or implied warranty or condition of merchantability, fitness for a particular purpose, or otherwise with respect to this product except as set forth herein. Under no circumstance shall absoluteBLACK or its third party suppliers be liable for any direct, indirect, incidental, special, consequential or any other kind of damages.
Cross-chaining happens when you use small front chainring and small rear sprockets (2-3 smallest sprockets). When the chain is in any of those gear combinations, the chain may come into contact with the front chainring and generate noise and/or unwanted chain pickup by the shift ramps. If this occurs, shift the chain onto the next largest sprocket or the one after. Those gear combinations should be avoided as they are bad for the entire drivetrain and can cause excessive wear and in more extreme situations, damage to the drivetrain. We strongly recommend to avoid riding in such gear combinations. Bicycle drivetrains are not designed to be used when cross-chained. Some setups might allow the chain to be shifted into such gear combinations, but this doesn’t mean they should be used. Modern electronic drivetrains will not allow to use cross-chained gear combinations.
The human body uses skeletal muscles to generate force on the pedals, predominantly during the downstroke. Each skeletal muscle has a unique characteristic that doesn’t allow even muscular force throughout its contraction. For example, peak joint power from the knee occurs at around 70 degrees crank angle (0 is at 12 o’clock), whilst the hip peaks well beyond 90 degrees crank angle. Further adding ankle joint power, angular velocity of the crank, inertia of the leg and the force effectiveness, which is how much of the force generated of the muscles is actually transferred to power, we can see that a power profile throughout a crank cycle is not even, but peaks somewhere around 110 degrees of crank cycle (normal road cycling, for example). AbsoluteBLACK oval chainrings are designed to perfectly fit a specific riding style and involve the hip joint to a larger extent, which essentially takes the load off the knee and adds to muscular efficiency. AbsoluteBLACK oval chainrings’ major axis orientation, that is when the chainring’s diameter is the largest, matches the power profile of a cyclist to reduce power losses and transfers the load from the knee to the hip. This was established based on several thousand measurements using one of a kind diagnostic equipment to measure 3D pedal forces and joint loading. Measurements were carried out on thousands of recreational road & mtb riders and hundreds of professional riders, including the entire Pro Tour Team UAE where we officially deliver our scientific biomechanical optimization services with our Science Lab. With such a wealth of data we are able to precisely design the chainrings that are able to increase the mechanical effectiveness – which means you perceive it as having less effort going at the same speed compared to round.
No. If we compare an aB round to oval narrow-wide ring there is absolutely no difference in the chain retention capabilities. But there is a difference among brands (regardless of the chainring shape). This is because every brand has designed the teeth differently and they will behave in a different way when they wear out a little or you use them in the mud.
Yes. absoluteBLACK offers a full range to fit all major frame mounting systems. The difference is mainly in the cage itself. It has to be taller and profiled differently to be able to cope with variable shape of the chainring.
Our oval chainrings are designed in a way that they always pull the same amount of chain at any position of the crank rotation. Imagine an ellipse which you can cut through the center at any place and it will always produce equal halves. The same is true for the circle. Because of this, chain wears in the same way as with the round chainring. It goes without saying that the best way to increase the life of any chain-chainring combination is to lube the chain regularly and keep it clean.
We have spent years in scientific research using the most sophisticated tools one can create in order to perfect the product. We posses the only scientific grade 3D force measurement system in the World that is capable of accurately measure forces on the pedal in every direction with a great accuracy, hip-knee-ankle angles, efficiency, mechanical effectiveness and so on. With such a device we are capable of measuring all the changes that happen when using different chainrings and to measure differences between the riders. Without such a device it’s impossible really to optimize the chainring to perform its best. We are the ONLY company that have such an equipment and a Science lab devoted to pedal optimization. Other companies are throwing darts in the dark so to speak.
With a properly designed oval chainring you are achieving a smoother pedal stroke. That means you smoothen out the peak forces when you pedal. It can be nicely observed when going uphill. You would notice much better rear wheel traction on loose terrain. This effect also translates to much smaller pedal bob during riding, which properly designed anti squat is aiming to remove. Therefore simply going oval reduces the pedal bob and improves your effectiveness regardless of the frame construction.

This is an interesting question without a definite answer. Our testing, that I mentioned above, revealed that somewhere between 8% and 14% yields an optimal result. But it very much depends upon the riding profile (e.g. road vs. MTB), chainring size, cadence and many other factors. We have optimized every chainring size and type to achieve the best possible result.

Our collected data on thousands of riders clearly show riders behave differently using different chainring sizes and riding different types of bike. To give you an idea, there is a very strong reason why someone is using a 36T chainring where someone else, in the same terrain, would use a 28T. Are these two hypothetical riders of the same level of fitness? Would they have the same power output, cadence, lactate threshold, body type or oxygen consumption?

But this is only part of the picture. The most important aspect in the oval chainring design is not only the ovality, but also the actual chainring shape and timing of the biggest radius of the chainring vs the crank arm. We optimize all of this per chainring size and type. Only then can we ensure a smoother and more effective pedal stroke that we are able to prove scientifically.

No. This only depends on the size of the chainring and frame construction since the chainring is not in motion.
If the oval chainring is designed correctly the movement of the derailleur cage is minimal and within a designed “play” of the clutch itself. We have spent a long time to make it right. When pedaling on aB oval chainring you see the chain is going up and down, but the real chain “feed” is constant. The tension on the chain returning to the pulleys is also constant. Some riders may report a slightly bigger movement simply because chainring was not mounted 100% centrally. Many lower end cranks have usually bigger mounting tolerances and they may allow to mount the ring slightly off center. If you see that cage is moving more than 1-2mm then you just need to remount the chainring again trying not to push the ring on any side. If you have a 4 bolt chainrings you just need to loose the bolts a little bit, then pedal on the stand and chainring will align itself. Situations like this are quite rare to be fair to impact the clutch in any meaningful way. We have not seen a single claim of clutch being damaged by the oval chainring. If this would be a common thing, we would not be in the place where we are now being the biggest aftermarket manufacturer of oval chainrings in the World.