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ShimanoUltegra SM-RT800 Disc Rotor

Sale 27% Off$42.99 - $44.99

Item # SHI00G6

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  • Gray, Centerlock 160mm ($44.99)
  • Gray, Centerlock 140mm ($42.99)
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Item # SHI00G6

A road brake stalwart.

It's hard to argue with the improves power and all-weather performance that disc brakes bring to road cycling. It’s a given in other cycling disciplines and we have already started to see some big names get important race victories aboard disc brake bikes. Shimano's Ultegra SM-RT800 Disc Rotors feature Freeza technology to cope with the sustained braking and higher temps associated with road cycling. This centerlock rotor continues Shimano's trickle-down technology from Dura Ace that further advances the Ultegra range.

Ice-Tech Frezza refers to the hybrid 3-layer sandwich construction of steel and aluminum. The stainless steel adds durability and consistent braking at the surface while the aluminum drops weight and helps dissipate the heat that can build up on long technical descents by up to 50-degrees Fahrenheit. When paired with Ice-Tech pads, temps that would normally be in the 400-degree range operate at a much lower 300-degree number. Lower temperatures improve braking performance and prevent fade for more confident descending.

The rotors are available in 140 and 160mm diameters and include a lockring.

  • Disc road rotor that adds powerful stopping in all conditions
  • Inner-aluminum core for maximum heat dissipation
  • Available in 140 and 160mm options
  • Centerlock hub compatible
  • Includes lockring
Tech SpecsWeight
Tech Specs
aluminum, stainless steel
Attachment Type
140, 160mm
Recommended Use
cyclocross, gravel, road cycling, triathlon
Manufacturer Warranty
2 years

Actual Weight

Actual weights are measured in-house by the Competitive Cyclist team.

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Gray, Centerlock 160mm
Gray, Centerlock 140mm

Claimed Weight

Claimed weights are provided by the vendor.

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[140mm] 106g, [160mm] 127g

Reviews & Community


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Awesome but tricky...

  • Familiarity: I've used it once or twice and have initial impressions

I purchased these to outfit my new carbon disc wheels and they matched, more or less, the bike without issues. Or so I thought. The disc for the rear wheel and cassette fit perfectly! But the front disc would not tighten properly, even though I was using the lock ring that came with the discs. It turns out that the Enve 3.4 disc wheel with Shimano front disc rotors requires a different lock ring before it'll fit onto the bike properly. Aside from this minor issue, everything is easy to install as long as you have the right Parktool (FR-5.2 GT). I'm sure that these will offer the same great stopping power as the current discs on my stock bike wheels since they are the same.

I'm building a wheel set with DT350 centerlock hubs and have read some confusing things about Shimano rotors, oversize lockings, etc.

Would I need any additional parts to fit these to those hubs, or are the included lockings the appropriate ones? Thanks.

Hey George,

You’ve probably already found an answer, so this is probably for the next person needing some insight. As a rule of thumb, if your wheels are quick release, the lock ring included will work. Thru-axles will work better with the oversized lock ring, but with the right cassette tool and a 12mm axel, it could work. I find the larger lock rings work great no matter what, and use the Shimano external BB tool (park tool BBT-19 or similar). Sucks Shimano doesn’t include them at this point, but that does keep the price down (in theory)

Great stopping power

  • Familiarity: I've put it through the wringer

These are quiet, reliable and offer great stopping pour in all conditions. The look might not be for everyone. They look like hub caps vs. traditional rotors. The larger the rotor, the more pronounced that look. I originally bought them bc I thought they look cool...I keep them because they work well but look just ok on my 2019 Roubaix.


  • Familiarity: I've used it several times

I have these set up on Reynolds 58/62 Carbon Disc Wheelset - Tubeless because I did not like the squeal I heard from carbon pads against carbon rims, and need the stopping power for canyon descents and wet conditions. I tested them up to 46mph downhill speed. They perform fantastic and stopped flawlessly!

Unanswered Question

Is there a 6 bolt equivalent to this rotor? I have switched wheelsets and need a 6 bolt rotor that is compatible with the Ultegra calipers. Thanks.

Roadie Rotors

  • Familiarity: I've put it through the wringer

Gone are the days when one had to defile their skinny-tire rig with mountain bike rotors. While a rotor is, ostensibly, a rotor, these feature fins that increase heat dissipation, and improve the aerodynamic profile (they also look ballin').

Feel free to let me know if you have any questions. I can be reached at jdraper@backcountry.com

Hi Joe, is it $49.95 for each one or the pair?

Great rotors that stay cool

  • Familiarity: I've put it through the wringer

These rotors are great and stop on a dime. They stay cool so they always provide maximum stopping power.


    I use them on my endurance bike, and they make me feel more confident going downhill.

    Which lock ring does this come with?
    Internal (sm-rt96) or external sm-hb20?

    Hey Mark,

    This rotor comes with SM-RT81.