Niner MCR — GRX/Ultegra 2×12 Road Build | Custom Build Review

Watch the full custom build walkthrough on the Maklin Bikes YouTube channel

This customer already owns a Niner MCR set up as a gravel rig and loves it — the kind of bike you can ride for hours. Rather than keep swapping wheels and tires, they wanted a second MCR set up more pavement-oriented for rougher road riding. Since Niner doesn’t currently offer a 12-speed GRX MCR, we built this one up from the frame as a custom 2×12.

Build Specifications
Frame
Niner MCR (Magic Carpet Ride)
Drivetrain
Mixed 2×12 – Shimano GRX 12-Speed Mechanical Rear Derailleur
Crankset
Shimano Ultegra 12-Speed, 50/34
Cassette
Shimano 12-Speed 11-34
Wheels
Spinergy GX32
Tires
Continental GP5000 All Season, 32mm
Seatpost
Whisky Carbon
Stem
Easton Alloy
Handlebar
Easton EC90 AX Carbon
Saddle
Placeholder (customer swapping in their own)

The Build

The Frame

The Niner MCR — Magic Carpet Ride — isn’t a bike we build a lot of, but this one had a clear purpose. The customer already rides an MCR as a gravel rig and loves how it rides for hours at a time. This second one is set up more pavement-oriented, for rougher road riding, so they don’t have to swap wheels and tires back and forth. You can still get these frames from Niner, but since you can’t currently order a 12-speed GRX MCR from them, we built this one up from the frame as a custom 2×12.

Drivetrain – Mixed 2×12

This is a bit of a mixed drivetrain, built to lean road. It runs a Shimano GRX 12-speed mechanical rear derailleur, paired with an Ultegra 12-speed crank and a 50/34 chainset up front to keep the gearing road-oriented, and an 11-34 12-speed cassette on the back.

One nice thing about the new 12-speed 11-34 cassettes: the jumps between the small cogs — your 11, 12, 13 — are tighter and more road-friendly than the old 11-speed spacing.

Wheels & Tires

The wheels are Spinergy GX32s — a cool, slightly different pick if you want something off the mainstream, and there was good pricing on them. Steve runs a set of Spinergy GXs for his own gravel riding; they ride nice and have held up well. They’re wrapped in 32mm Continental GP5000 All Season tires — we talked about going faster, but wanted a bit more durability without dropping all the way to a heavy protection tire like a Gatorskin.

Cockpit

Up front it’s a Whisky carbon seatpost, a basic Easton alloy stem, and Easton EC90 AX carbon gravel bars. Those EC90 AX bars have been going out the door constantly lately — we had three sets come in just this past week — and they’ve become our go-to carbon bar upgrade on gravel bikes. The saddle on the bike is a placeholder; the customer is swapping in their own.

The Bottom Line

A purpose-built second MCR

Almost none of our gravel bikes leave the shop in stock form anymore — nearly everything gets some kind of custom treatment, and this MCR is a good example. It’s smooth, it’s set up exactly the way this rider wanted it, and it gives them a dedicated pavement bike without touching their gravel rig. Builds like this are the fun part of the job.

Want a Custom Build Like This?

We build custom gravel, road and mountain bikes at Maklin Bike Shop in Scandia, MN. Tell us how you ride and your budget, and we’ll put together a proposal.

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