Shimano Deore 12-speed: First Ride Review + Actual Weights + M6100 Karate Monkey Build

By Logan Watts and TJ Kearns

Almost like clockwork, Shimano has released a new 12-speed drivetrain every May since the original 10-51t Shimano XTR launch in 2018. The technology made its way to 12-speed XT and SLX last May, so we weren’t shocked to see it trickle down even further to Deore level components this year. However, we were kind of surprised to see how nice it looked. While the Deore groupset retains some core technologies, such as Hyperglide+, the Micro Spline Freehub, and Shimano’s Dynamic Chain Engagement+, it offers a more value-forward approach. And it also boasts clean lines and nice aesthetics. The new M6100 series includes a complete Shimano Deore 12-speed drivetrain (new cranksets, chain, cassette, derailleur, and shifter), as well as a dropper lever, brakes, and hubs. We were happy to get our hands on the full Deore group to weigh, install on a new Surly Karate Monkey, and put together some first impressions on the drivetrain and brakes. Find details and original photos of each of the components below, followed by our first impressions, and grids for pricing/weights.

The beauty of the new Shimano Deore group is that it allows you to assemble a very solid wide-range drivetrain for under $300, or a complete kit with 4-piston hydraulic brakes for just under $600. In the past, SLX and Deore usually meant slightly heavier materials, or more material, used throughout the components, which isn’t necessarily bad when it comes to durability. In fact, we’ve built several bikepacking rigs around such components for that very reason. It appears the Deore 12-speed group is no different. It has slightly more steel and metal throughout, and seems pretty burly… in a good way.

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Deore/Surly Karate Monkey Build

Weight: 29.4 pounds (13.34 kg)
Total build price (more details below): $2,127.87

With the new group in hand, it only made sense to tackle a logical new build. The Shimano Deore 12-speed group is a no-nonsense, budget groupset that combines Shimano’s legendary shifting performance at a cost that won’t break the bank. Likewise, the Karate Monkey is Surly’s no-nonsense steel hardtail that will take you anywhere, last forever, and also won’t break the bank. Together, these two make for a super solid build. Sure, it’s not the latest electronically shifted, space metal superbike, but it’ll get you there reliably and you’ll have money left over for that big trip you’ve been scheming. Plus it’s a Surly—in the event of an[other] apocalypse, there will be cockroaches and Surlys!

• Frame/Fork Surly Karate Monkey (small)
• Fork Surly Karate Monkey
• Wheels Shimano MT620 (SLX), 29er, 30mm Internal Width, 24-spoke
• Front Tire Teravail Honcho 29 x 2.6″
• Rear Tire Teravail Ehline 29 x 2.5″ (Light and Supple)
• Crankset Shimano Deore FC-M6120, 55mm Chainline (Boost), 170mm arms, 32T Chainring
• Derailleur Shimano Deore 12-speed M6100-SGS
• Shifter Shimano Deore 12-speed M6100-IR (I-SpecEV)
• Chain Shimano Deore 12-speed CN-M6100, 126 links
• Bottom Bracket BB-MT800
• Brake Levers Shimano Deore BL-6100
• Brake Calipers Shimano Deore BR-M6120, Metal pads
• Handlebar Pro Koryak 760mm, 20mm rise
• Stem Pro Koryak 70mm +-6°
• Grips Pro Lock-on Trail
• Saddle Ergon SMC
• Headset Cane Creek 40
• Seatpost Thomson Elite 30.9mm

Shimano Deore 12-Speed FC-M6120 Crankset

The new Deore 12-Speed crankset is a standard two-piece 1×12 only crank specced with either 30T or 32T direct mount chainrings. There are three different versions to accommodate different chainlines: FC-M6130-1 for 157mm Super Boost Frames (56.5mm chainline), FC-6120-1 for 148mm frames (55mm chainline), and FC-6100-1 for 142/148mm frames (52mm chainline). Each is available in two different crank arm lengths: 170mm and 175mm, and features new color-shift graphics that change depending on the light. We mounted the Boost/148mm (FC-M6120-1) with 170mm arms and a 32T ring.

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The biggest difference between the Deore crankset and the SLX/XT is that unlike the SLX/XT cranks, which use hollow crank arms, the Deore cranks use solid forged arms. This allows Shimano to keep the price down, but it also increases the weight of the cranks by 150g over the SLX model and 160g over XT. Deore chainring sizes are also limited to 30 and 32 toothed options. And, it’s worth noting that the chainring appears to have eight bolts that secure it to the spider, they’re actually more like rivets that are not meant to be removed. Replacement chainrings will only be available for purchase with the full direct mount spider.

• CHAINRING: Direct Mount, 30T or 32T
• CRANK ARM LENGTH: 170mm or 175mm
• PRICE: $94.99 USD

Shimano Deore 12-Speed CN-M6100 Chain

The new M6100 series 12-speed chain shares similar characteristics as the SLX-level M7100 chain but without the added durability offered by SIL-TEC treatment. Plus, it’s $8.00 cheaper. Like other Shimano 12-speed chains, it has Hyperglide+ Shift Technology, Extended Inner Link Plate, and includes a quick link.

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• Number of Links: 126
• PRICE: $23.99 USD

Shimano Deore 12-Speed CS-M6100-12 Cassette

The Deore 12-speed cassette is 100% steel with a 7-cog pinned spider and five additional cogs with two spacer rings. Similar to the SLX cassette, it has a cog combination of 10-12-14-16-18-21-24-28-33-39-45-51T. Ours tipped the scales at 595 grams, about 60 grams heavier than SLX and 125 grams heavier than XT.

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• Gear Range: 10-51T (510%)
• Driver Interface: Micro Spline Interface
• Cogs: 10-12-14-16-18-21-24-28-33-39-45-51T
• PRICE: $91.99 USD

Shimano Deore 12-Speed M6100-IR Shift Lever

On paper, the Deore 12-speed M6100-IR shift lever is quite similar to the higher-end SLX shifter. It offers Shimano’s Rapidfire Plus Shifting, two-way release, and is I-SPEC EV compatible for increased adjustment. It’s fair to say that the Deore lever may require slightly more operation force than the SLX lever, and noticeably more than the XT shifter, but it still feels pretty good. The Deore shifter weighs about 60 grams more than the SLX model.

• Options: Optical Gear Display
• SL-M6100-IR: I-SPEC EV
• SL-M6100-R: Band Clamp
• PRICE: $31.99 USD

Shimano Deore 12-Speed RD-M6100-SGS Rear Derailleur

The Deore 12-speed rear derailleur is fairly impressive considering its price and place and position in the Shimano hierarchy. It still features a Shadow RD+ clutch mechanism for increased chain retention and shifting accuracy, and the rear pulley cage has the same new bumper as its more expensive siblings. While the overall build may not be as refined as the SLX 12-speed derailleur—a different alloy cage, etc.—they are quite close, and this one weighs just 10 grams moret.

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• Pulley: 13T Pulley
• Max Cog Size: 51T
• PRICE: $54.99 USD

Shimano Deore Brake Levers and Calipers (BL-M6100/BR-M6120)

For the first time ever, Deore-level brakes see a 4-piston variation to make a well-performing MTB brake at a reasonable price point. Both the 4 and 2-piston callipers see a complete redesign with ICE-Tech brake pad compatibility, and inboard hose routing for a cleaner setup. A single new Deore lever (BL-M6100) is used for both calipers, which has a wider, more durable clamp, a new lever axle position, and refined ergonomics. The main difference between it and the SLX lever is that it doesn’t have the tool-free lever position adjustment knob.

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We installed the BL-6100/BR-M6120 combo. According to the box, these come with either resin or metal pads, and a 1000mm or 1700mm hose, depending on front or rear. We got the metal pads. The lever is also I-SPECEV compatible.

• BR-M6100: 2-piston brake caliper
• BR-M6120: 4-piston brake caliper
• LEVER PRICE: $29.99 USD
• CALIPER PRICE: $36.99/$64.99 USD

Shimano MT620 Wheelset

The MT620 wheelset is a trail-oriented wheelset. The wheelset comes with a 30mm wide (inner width) aluminum rim laced to a Shimano Centerlock microspine hub with 24 double butted J-bend spokes holding it all together. Shimano ships the wheels with tubeless valves and tape pre-installed. This is actually the SLX level wheelset (not Deore), but it appears that the Deore wheels are quite similar. The wheelset is available in 27.5 or 29 with options of 15×100/15×110 front spacing or 12×142/12×148 rear spacing and is only compatible with Centerlock rotors.

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• Spokes: 24 double butted J-bend spokes
• Weight: 2,233 grams
• Wheelset Price: $245.99

Shimano Deore 1×12 Installation

Installing this group was a relatively straightforward process, except for the chain. For those unaware, Shimano 12-speed has slightly different chain sizing guidelines than other drivetrains. TJ was a full time bike mechanic for many years but left the shop just after the new Shimano 12-speed drivetrains came out, so he wasn’t familiar with their new sizing procedure. Here’s how it’s done…

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To calculate the chain length for the Karate Monkey hardtail, we wrapped the chain all the way around 32T chainring and 51T cog, figured out where the closest link met, then added four links total plus the quick link. For a full-suspension bike, you’d use the same process but add five links plus the quick link to compensate for chain growth under suspension travel. Dans Bike Blog probably has the most clear visual diagrams.

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Installing the I-SPEC EV shifter to the brake lever mount gave the bars a nice clean look, but Shimano also sells the shifter with a standard 22.2 mount if you run other brands’ brakes. Rear derailleur tuning was very easy and the shifting was crisp and defined. Installing the brakes only required a top bleed after cutting the hoses to length and the bedding in process of the pads went smoothly.

As for the wheels, installing Teravail’s 2.6” Honcho and 2.5” Ehline was a pretty straightforward affair and they set up tubeless without the need for a compressor or a fancy tubeless pump. At 1243g for the rear and 990g grams for the front, this is definitely not a lightweight wheelset. And, they’re only available in 24-spoke, which would be a questionable choice for heavier riders or heartily packed bikepacking rigs. That said, the spokes are a heavy gauge, so only time will tell.

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Shimano Deore 1×12 Actual Weights

• Crankset 778 grams
• Rear Derailleur 319 grams
• Shifter (with cable) 195 grams
• Cassette 595 grams
• Chain (uncut) 279 grams
• DEORE M6100 drivetrain only 2.17 kg (4 lbs, 12 oz)
• Front Brake (Caliper/Lever/Hose) 312 grams
• Rear Brake (Caliper/Lever/Hose) 329 grams
• Bottom Bracket (MT800) 77 grams
• DEORE M6100 Group Total 2.88 kg (6 lbs, 6 oz)
• Rear Wheel 1243 grams
• Front Wheel 990 grams
• Wheelset Total 2.23 kg (4 lbs, 15 oz)

The Deore drivetrain (shifter, cassette, crankset, chain, and derailleur) weighs about 320 grams over the claimed weight of the SLX system and 421 grams more than XT’s claimed weight. We’ll be sure to get actual weights and confirm soon.

Shimano Deore 12-Speed Pricing + Build Kit

• Deore 10-51T Cassette $91.99
• Deore 12-Speed Chain $23.99
• Deore 12-Speed Rear Derailleur $54.99
• Deore 12-Speed Shifter $31.99
• Deore 12-Speed Crankset $94.99
• DEORE M6100 drivetrain only $297.95
• Disc brake F (4-piston) $149.99
• Disc brake R (4-piston) $149.99
• DEORE M6100 group total $597.93
• DEORE MT620 Wheelset $245.99
• Pro Koryak Riser Bar $69.99
• Pro Koryak 70mm Stem $79.99
• Pro Lock On Trail Grips $29.99
• Karate Monkey Frame $700
• Teravail Honcho $65
• Teravail Ehline $70
• Ergon SMC Saddle $79.99
• Thomson Elite Seatpost $114.99
• Cane Creek 40 series $74
• Total Build (including frame and Deore Group) $2127.87

The Deore 12-speed group offers a good value for an aftermarket 1×12 drivetrain. As expected, the drivetrain costs significantly less than both XT and SLX 12-speed groups, which retail for $622.93 and $409.93, respectively.

Why is this build so expensive?

While the Deore 1×12 group is relatively inexpensive, you might be wondering why the “budget” build is more costly than most entry level rigid bikes, like many ~$1,500 complete bikes. The answer is in the details. Typically, a budget complete build is loaded with cheaper, OEM parts, such as headsets, cranks, and cockpit parts. While Deore is the lowest line in Shimano 12-speed group hierarchy, it’s certainly not cheaply made or nearly as bottom-of-the-line as many OEM specced parts.