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Build Overview
The Niner MCR—MCR stands for Magic Carpet Ride—is one of the most unique bikes in Niner’s lineup, and this customer already owns one set up as a gravel rig. They love the comfort and ride quality of the MCR, so instead of swapping wheels and tires back and forth, they wanted a second MCR built specifically for rougher pavement and all-day road endurance riding.
Niner doesn’t currently offer a 12-speed GRX build for the MCR, so we put this one together as a custom mixed-drivetrain setup. The build blends the new 12-speed GRX rear derailleur with an Ultegra 12-speed road crank and a compact 50/34 chainring combination to create a more road-friendly gearing setup, perfect for the customer’s intended use.
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Full Build Specs
- Frame: Niner MCR (Magic Carpet Ride)
- Drivetrain: Shimano GRX 12-speed (mech) with Ultegra 12-speed compact crank
- Crankset: Shimano Ultegra 50/34
- Cassette: Shimano 12-speed 11–34 (road spacing)
- Wheels: Spinergy GX32
- Tires: Continental GP5000 AS (32mm)
- Seatpost: Whisky carbon seatpost
- Stem: Easton alloy stem
- Handlebar: Easton EC90 AX carbon gravel bar
- Saddle: Placeholder (customer swapping in their preferred saddle)
Build Notes
This MCR build came together with a very specific purpose: create a pavement-oriented version of the customer’s existing gravel MCR so they wouldn’t need to keep swapping wheels and tires. This platform is already incredibly comfortable thanks to Niner’s CVA suspension system, and paired with the right tires and gearing, it becomes an excellent rough-road endurance bike.
Since Niner doesn’t currently offer a 12-speed GRX complete for the MCR, we built this one from the frame up using a mixed Shimano drivetrain. The GRX 12-speed rear derailleur integrates cleanly with the Ultegra 50/34 compact crank and an 11–34 cassette. The new 12-speed Shimano road cassettes are especially nice because the smaller cogs have tighter, more “road-friendly” jumps compared to older 11-speed setups.
The wheels are Spinergy GX32s—kind of a unique choice and a fun option if you want something different than the mainstream brands. We’ve had good luck with Spinergy’s GX lineup, and there happened to be great pricing available. They’re paired here with 32mm Continental GP5000 AllSeason tires for a blend of durability and performance without going all the way to a heavy touring or protection tire.
For the cockpit, we used a Whisky carbon seatpost for added comfort, an Easton alloy stem, and Easton EC90 AX carbon bars. These bars have been extremely popular for us lately—we’ve installed several sets just this past week. They offer a nice ergonomic top, comfortable reach, and a shape that seems to work well across a wide variety of riders, especially in gravel and endurance positions.
The saddle on the bike in the photos is a placeholder—the customer is swapping in their preferred seat. Overall, the bike turned out great. It’s purpose-built, smooth, and fits exactly how the rider plans to use it. Most of our gravel bikes haven’t been leaving the shop in stock form lately—almost everything is getting some kind of custom treatment. Builds like this are what make the job fun.
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Work With Us On a Custom Build
If you’re thinking about a custom gravel, MTB, or road build, we can help you spec it out, match the components to your riding style, and build it right.