Some riders swear by them, others aren’t so convinced. Oval chainrings can be a bit marmite, but are certainly here to stay, with Absolute Black dedicated to the cause. As a physio and bike fitter, the explained science behind the advantages of oval rings makes sense as a means to increase pedalling efficiency, but the proof is in the riding.  I have been putting in some hefty km on a set of Absolute Black’s sub-compact rings, installing their 32/48 combination on a Praxis Alba chainset as a gravel oriented set up.

Due to Praxis’ proprietary design to have a 32 chainring fit into a 110pcd, there isn’t a choice of ratios for this chainset, so Absolute Blacks’s 30/46 combo won’t fit. The specific sizes are designed to work intimately together, with tooth shape and position optimised for maximising shifting performance.

The chainrings vary slightly in their % ovalisation. It is subtle, but this is said to optimize efficiency for each ring due to the generally different pedalling torque through each ring, i.e. flat to rolling terrain for the big ring,  inner for more sustained climbing or steeper inclines.

Unpackaged, the rings feel light, yet solid, like they would be unwaveringly stiff under some powerful legs. As with the original Praxis chainrings, these have the thread within the inner ring, the outer bolts directly the inner.  Bolts are provided being a proprietary size with the thoughtful feature of having threads coated in a loctite compound. Installation is straight forward, a tiny peak on each ring indicating orientation under the crank arm. The only technical part is rearranging the front derailleur, moving it up to clear the ring’s high point. Full instructions can be found on the website here. Chain length stays the same and I used an 11spd Shimano 105 with quicklink which worked just fine.

Adaptation

Fitted and eager to get out, living in the Alps, both inner and outer rings get full use on every ride. Those first few km along flat terrain did feel awkward, pedaling felt lumpy as each foot came over the top of the pedal stroke. Expecting a performance increase,  it felt  odd initially, almost as though more  effort was required over familiar valley terrain and local hill climbs for a given speed. Overly expectant of an immediate positive outcome, I had to remember that years of teaching yourself to ride in a particular way, to pedal in efficient circles overcoming the upper and lower dead spots, had to be unlearnt. Riding oval means learning a new movement pattern, which, like learning any other skill, takes perseverance and time before it feels normal. This adaptation period will be different for everyone. I had over 25 years of riding round rings in the legs and am of a ‘certain’ age. Younger and relatively new riders may find their adaptation experience is faster. Personally, it was around 15 hours before pedaling felt smooth and relaxed, eliminating the deliberate effort of pedaling through the 2 dead spots. The oval rings now felt ‘round’, although, overall, I have felt that the gains from riding oval have become more apparent over the course of months rather than simply from the point where they felt smooth to ride.