AbsoluteBlack has been making intricately machined oval chainrings for some time, and they’re beautiful. They’re also expensive, so this past spring, they came out with the Winter set for road. Winter being another way of saying “off season”, or “training” rings since they’re a bit heavier and lose the machining on the outer face of the large chainring. That makes them more affordable, but they don’t have the chiseled look of their Premium Oval chainrings, tested here.
The shaping isn’t just cosmetic or to save weight, it also boosts strength and stiffness, aided by their 5mm thickness. Which works, these are incredibly stiff. They also happen to shift smoothly and quickly, and even with a moderate ovalization, slot into modern drivetrains with minimal or no issues…
I tested a 50/34 combo built for Shimano’s current asymmetric 4-bolt pattern. The large chainring comes in at 122g, the small at 31g and the nut-and-bolt package at 8g. For comparison, the Winter 50T chainring comes in at a claimed 156g.
They were mounted on an Ultegra crankset, whose stock chainrings weighed in at 113g, 33g and bolts at 5g. Shimano’s chainring bolts thread directly into the large chainring. Total weight gain from the switch: 10 grams.
Front side machining is left showing the ridges, unpolished, and there are no covers to morph the shape into Shimano’s arms. Regardless of these missing finishing touches, they blended into the cranks well enough for my tastes. Over a few weeks of testing, the bolts never came loose, which bodes well for their long term use.
The backside gets a total of six upshift ramps, also machined. As in, not forged or stamped.
If you’ve made it this far, you’re either already an oval chainring convert, or your oval curious. For the latter, here’s the elevator pitch: They maximize your leverage in the most powerful part of your pedal stroke, and make it easier where you’re weakest. The net effect is that your pedal stroke feels smoother, more circular. The pic above shows how the tallest part of the chainring, which acts like a higher tooth count, is pulling the chain where you’re putting the most force downward on the pedals.
As you come into or exit your power zone, the effective diameter is lower, making it easier. The actual ovalization is only 10.3%, so it looks and sounds more dramatic than it really is, but it works. AbsoluteBlack doesn’t offer adjustable angles like Rotor, instead settling on a position that they’ve tested to be generally very efficient for the average rider.
Our test rings came with one caveat – they don’t recommend riding the smallest three cogs while in the small chainring. Why? Because with the taller part of the oval sticking out further, it could rub or catch the chain inadvertently. The pics above show it in both extremes (click to enlarge). Fortunately, it ended up with clearance throughout the entire range of the cassette on our Parlee Chebacco test bike.
I raised the front derailleur slightly so it would clear the large chainring in its high point rolled past the cage. And with that, all adjustments necessary to run these oval rings in place of the stock round ones was done. Granted, Di2 was a bit easier than with a mechanical system, but still.
With that caveat in mind, or perhaps because of it, the smooth shifting seemed all the more impressive. Up and down shifting was on par with the Ultegra rings these replaced, which is about as high a praise I can give them. I degreased the chain and gave it a fresh coat of Smoove chain lube prior to swapping the rings, and with that the entire drivetrain ran quietly. Under stand-up-and-mash-the-pedals power, they didn’t seem to flex, as measured visually and by the lack of rubbing the front derailleur cage. Oval or not, AB’s Premium chainrings live up to the top level billing.
As for ovality in general, I’m a fan. AB’s founder Marcin says average riders are going to notice the biggest difference (“improvement” in his words), much more so than “pro” riders that have fine tuned their pedal stroke. I’m not sure what that says about me as a rider, but I like them, particularly on my mountain bike with a 1x setup, but here, too. On a mountain bike, the biggest gains to be had seem to be with improved traction thanks to a smoother, more consistent application of power. To test that on the road, I found an incredibly steep concrete service road (above, on the left, not the dirt one) and rode up it. Standing and grinding up the 18% grade at about 3mph, I noticed that rather than bobbing up and down on the pedals. My body was floating in the same space as my legs cranked underneath. And the bike didn’t lurch forward like it usually does on such steeps, it just kinda maintained a steadier forward momentum. Sustained seated climbing up less steep but longer ascents also seemed smoother and more efficient. Overall recommendation: Worth it.
The Premium Oval chainrings for road retail for $124 for 50/52 large rings, and $61.95 for 34/36/38 small rings. They’re available in black, red and racing gray (tested), for Shimano 4-arm asymmetric cranks only as of this review. Five-bolt 110bcd and 130bcd options are coming soon.