Shimano debuts new warp-resistant road disc rotors for quieter braking

Say goodbye to noisy brakes on long downhills?

by James Huang

photography by Shimano

“Ting, ting, ting!”

It’s the sound that many roadies with disc brakes know all too well, particularly on longer downhills. As disc rotors get hot, they can sometimes warp just enough to lightly contact the pads, causing that telltale soundtrack until things cool down a bit. Shimano had already officially endorsed the use of its more robust mountain bike rotors for the latest-generation Ultegra Di2 and Dura-Ace Di2 electronic groupsets to help address the issue, but now the company is announcing two road-specific rotor designs that should be a better aesthetic match.

According to Shimano, the new RT-CL900 and RT-CL800 feature a “more robust alloy carrier and arm shape” that “significantly reduces heat deformation during long, steep descents.” Essentially, Shimano is claiming the new rotors are better able to stay true as they get hot so pad rub doesn’t become an issue.

Offered only in 160 and 140 mm diameters for now, the new rotors also incorporate Shimano’s long-running Ice Technologies Freeza design elements, including a three-layer sandwich design with steel braking surfaces and an aluminum interior connected to cooling fins to help dissipate heat. 

Claimed weight for both rotor models is identical at 114 g for the 160 mm size and 96 g for the 140 mm one (which, interestingly, is a few grams heavier than the mountain bike rotors Shimano previously recommended for Dura-Ace and Ultegra). Retail price is US$86 for the RT-CL900 and US$61 for the RT-CL800. Pricing for other regions is still to be confirmed.

More information can be found at

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