After chainrings, one of absoluteBLACK’s earliest products was an ultralight disc brake rotor called the Ravel SL. Now, 14 years later, they’ve introduced v2, with less focus on weight and more attention paid to performance. Just not in the way you think.
If you look at most modern rotors, there’s a proliferation of slotted designs. The goal is to create gaps for cooler air to flow through and keep the rotors from overheating. absoluteBLACK says there’s a problem with this – all those slots cause uneven pad wear, which leads to lower braking performance.
They started figuring this out while developing their GRAPHENpads brake pads. With regular slots, or other common designs, there’s a big difference in the amount of metal making contact with the pad as you move outward from the center of the rotor.
And, because the circumference at the inner part of the circle is smaller than the circumference at the outer part, a slot that maintains the same shape actually allows for a different amount of surface contact across the rotor’s surface.
The important part of that finding is that the heat created differs in relation to how much surface area the rotors are touching. And if that material contact is different, than the heat is different, which means things start to get weird. The area of the rotor producing more heat starts to lose performance before the rest of the rotor. What feels like brake fade is really just part of the rotor losing friction compared to other parts.
absoluteBLACK’s solution was to even out the amount of material the brake pad saw. The TL;DR version is this: Holes need to be sized and placed so that the brake pads see the same amount of material at every point on the rotor’s circumference.
Obviously, there will be increased material at the inner and outer areas where there are no holes, but getting it as even as possible everywhere in between took them years of testing and resulted in more than 500 individual perforations. They call it a “mathematically uniform braking path.”
And then they adjusted the design for harmonics, steel hardness, surface finishing methods, and manufacturing complexities.
And here we are, with the new Raven SL and Raven GT brake rotors. The SL gives up a tiny bit of these findings to save weight, and the GT is fully optimized for evenly distributed braking power. Options include:
- 6-bolt
- RAVEN SL 160 mm — 85g
- RAVEN GT 160 mm — 99g
- Center Lock
- RAVEN SL CTRL 140 mm — 81 g
- RAVEN SL CTRL 160 mm — 94g
- RAVEN GT CTRL 160 mm — 108g
Worth noting, these are designed only for road and gravel bikes, not MTB. Prices range from $159 to $172, available now. The center lock ring shown in some photos is sold separately.
