The next generation of perfection.
Nobody puts more thought into brake rotors than Shimano, and the SM-RT99 XTR Race CenterLock Disc Rotor is proof of that. The hybrid steel and aluminum construction saves weight and manages heat buildup. Even better, it's been topped off by Shimano's lightweight and user-friendly CenterLock hub/rotor interface.
While it's awash in complex Japanese tech, the rotor's main job is still a simple one: to scrub speed. That makes the braking surface the most important part, and it's shiniest highlight is Shimano's IceTech construction, which involves bonding two stainless steel braking tracks to an aluminum inner-core in a speed-scrubbing sandwich.
Although this bond is exposed to a great deal of heat and friction, we've yet to experience any separation of the layers over hundreds of hours of ride time—even for gravity sessions—and the benefits are well worth the non-risk. Not only does IceTech result in a lighter weight rotor, but the aluminum core sheds heat faster than a standard steel rotor. By reducing heat buildup in the brake system, your brakes provide more consistent power while simultaneously reducing the risk of boiling the brake fluid.
Shimano's obsessive attention to detail is also immediately visible when looking at the alloy cooling fins. Those wavy inserts on the inner-diameter of the braking track aren't just for show. In fact, they're the latest evolution of IceTech construction. The fins channel heat away from the braking track, which dissipates heat into the air instead of channeling it back into your brake caliper. This equates to even more effective heat management than the previous generation, the SM-RT98 XTR IceTech rotor.
To keep the weight to a minimum, Shimano attaches the braking surface to an aluminum spider. And since those grams add up, the spider attaches to the hub via Shimano's CenterLock rotor mount standard. This attachment method saves weight over a six-bolt hub and rotor, and it has the added benefit of making rotor-swaps much quicker.
Please note that these rotors will only work with CenterLock hubs, and they cannot be adapted to six-bolt hubs. If you need a Shimano IceTech rotor for six-bolt hubs, consider the SH-RT86 XT IceTech rotor.
- A top-tier disc rotor for unrivaled stopping power
- IceTech construction manages heat to maintain responsiveness
- Cooling fins scrub heat while scrubbing speed
- Temper's XTR speed with equally impressive braking