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So far, Shimano has had a head start in the fancy-rotor game with the aluminum-sandwich Ice Tech concept and heat-sink-equipped Ice Tech Freeza. The goal behind Shimano’s design is to keep the brake from overheating, but other brands are taking a simpler approach. Hayes and TRP, for example, use rotors that are considerably thicker than we’re used to seeing. There’s simply more mass to absorb energy (heat), so thicker rotors tend to stay cooler. That’s exactly the approach SRAM took with the new HS2 rotors just released today.
At 2 millimeters thick, the HS2 is about 0,15 millimeters thicker than the SRAM Clean Sweep rotor we measured (there’s no published info on Sram’s previous rotor thickness). That may not sound like much, but there was no need for a change in caliper or pad, and it still adds up to a more than 7-percent increase in thickness.
And that’s just part of what makes the new SRAM HS2 rotors special. The alternating recessed “spokes” are coated with a heat-dissipating paint (similar to Ice Tech Freeza) and result in a 40-degree-celsius decrease in temperature. If this graph is to be believed, that benefit is sustainable over several minutes of braking, so it’s a benefit that may be hard to overwhelm.
All that, combined with a newly shaped pad track, SRAM claims a 7-percent increase in braking power. The HS2s come in both center-lock and 6-bolt, and in 160, 180, 200 and 220mm diameters. And the price ain’t bad. $50, $55, $6o and $65 (respectively), regardless of 6-bolt or center-lock. That’s about $30 cheaper than a Shimano Freeza rotor. SRAM expects HS2 rotors to be hitting store shelves this month.