After Shimano withdrew their Biopace chainrings from the market, any attempts to relaunch oval chainrings were often ridiculed. Nevertheless, they are still available, and brands such as Absoluteblack are even successfully filling this niche. During the last bike season, a wide variety of tests were carried out to find out what the "eggy" chainring is all about.

Before the start of the season, the original 32 mm X01 chainring from Sram was replaced with an oval 34 mm GPX chainring for 1x11 shifting systems from Absoluteblack. Corresponding chainrings are also available for most crank systems. Why did I choose a larger chainring than I had before? For one thing, there were a few enduro races on the program, where the 32 mm can be a bit tight. On the other hand, it was curiosity as to whether the supposedly better power transmission would make up for the greater effort required.
The question also arose as to whether the chain would hold onto the chainring as well as the original from Sram. For this reason, I decided not to use a chain guide or safety device, as is usually the case in enduro races.

From assembly to the first pedal rotation

Absoluteblack has tested the optimum shape and position and only allows one mounting position. This means you, or the bike mechanic, don't have to worry about the chainring being mounted in an ineffective position. This simplifies the work considerably. It is important to clean the chainring mount on the crank and to treat the connection with some resistant grease so that no cracking noises occur later. Before screwing in the bolts, a drop of threadlocker does not hurt either.

At the specified position, the oval blade should do exactly what the predecessor "Biopace" should have done - ensure better power transmission. It should also reduce the peak loads on the joints and increase traction. That's quite a few nice promises.

The before and after test in the parking lot already let me feel the difference. The pedal really did feel a little rounder. When pedaling hard, however, I noticed a slightly greater twist than with the original from Sram.

The off-road ordeal

What was already noticeable during the parking lot test became clear on the first few rides uphill. The oval shape of the Absoluteblack chainring leaves a very pleasant pedaling sensation. Climbs that I have often ridden with the round 32 t chainring before are the best reference for me. The two extra teeth are noticeable - the cadence is lower in the lightest gear. But there is no choking, even when it gets steeper. The fact that the pedaling has become much more harmonious and that the muscles don't tire as much on longer tours despite the larger chainring are convincing arguments for the Absoluteblack Oval. As my knees occasionally get a bit twitchy, I can also confirm the statement about the lower stress peaks on the joints - even with the 34 t chainring.

The first enduro race is coming up. It's pouring with rain and for once I'm not at all interested in the power transmission. During the downhill stages, the bike fills up with mud and the drivetrain is also getting clogged up. Despite the smallest pebbles, blades of grass and dirt in the drivetrain, the chain stays in place. The blade has already mastered this first test well.

Dust-dry trails, long descents and rough terrain await me in the following enduro race. So if the chain falls off, it should happen at this race. But that doesn't happen. It is securely guided on the teeth as if it were the original X01 chainring.
At the same race, there are also some tough counter-climbs to tackle in the downhill stages. The twisting initially felt in the parking lot is not noticeable on the short ramps in the race. The power is transferred perfectly when sprinting. Conclusion
With the oval chainring from Absoluteblack, you won't ride faster on the Tour or win a race because of it, but it is still impressive. It allows a more harmonious pedal stroke, reduces stress peaks on the joints and improves power transmission, which is particularly beneficial on long climbs. The chain stays on the chainring in practically all situations without a chain guide, even after the chainring has been used for a season. Absoluteblack has therefore not made any empty promises with its Oval - a tip for all bikers who like to optimize their bikes.

www.absoluteblack.cc