While direct mount rings from the big brands and aftermarket providers have easily dropped their tooth counts down into the twenties, getting an oval chainring with less than a 32-tooth spread for four-arm spiders has been a challenge. Now, thanks to some clever engineering, AbsoluteBlack has managed to dip down to 30 teeth while still using a standard 104bcd mounting pattern. It just took seven months of testing and a couple non-standard parts…
The issue with making an oval chainring smaller than 32 tooth is that at least two of the chainring bolts would be sitting inside the space used by the teeth. If you used standard M8 threaded inserts and bolts, that is.
AB’s solution was to use smaller M5 bolts, similar to what’s used to hold your disc brake rotors on the hub, with eccentric spacers.
These provide the clearance needed without invading the chain’s personal space, letting you run a 30-tooth oval on your 104bcd cranks. The ovality is the same as their other rings, so there’s no difference in pedaling feel or performance if you’re already using their larger rings.
Claimed weight is 36g for the ring and 7g for the included hardware (two alloy M8x8mm bolts + two stainless steel M5x8mm bolts + two spacers). Retail is $74 (€64.50 / £52).
FWIW, they also mentioned that their narrow/wide chainrings are compatible with SRAM Eagle 12-speed chains and drivetrains. Here’s Absoluteblack founder Marcin’s statement:
“(We want to point) out that our entire range of chainrings is also compatible with the new SRAM Eagle 12spd drivetrains. This is a response to a commonly asked question. There is no need for special hooked tooth shape in order to get things working properly. SRAM has marketed their new rings as the only ones that will work with Eagle chain and cassette. But fact is that the chain has changed only minimally in dimensions versus the 11spd one and we already have done a small running adjustment (before Eagle became available) to our Absoluteblack chainring tooth thickness to accommodate the changes to the new SRAM Eagle chain.”
