Shimano Deore M6100 groupset review

Shimano didn’t just get outflanked by SRAM’s shift to single ring transmissions, they got totally routed by it as bike designers seized the many packaging and spec advantages of ditching the front mech and made double-ring transmissions look like dinosaurs. They were late to the 12-speed party too and then threw up all over the new carpet with a glitch infested XTR introduction. XT and SLX started the fightback in impressive fashion though and then Deore showed up. It’s really shaken up the bottom end of the big cassette market by not only working great but looking great too. As good as it is as a complete setup, a few smart upgrades make it an even better way to propel your MTB for a total bargain price.  

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Cranks 

Having just raved about overall performance it seems a little mean to start with the most obvious component to replace but it’s all about context. The Deore cranks are lovely looking things that run the same direct pattern as their Shimano siblings. That means while you can only get Deore rings in 30 and 32 tooth sizes you can get SLX that fit in 34T and XT in 28 right through to 36 teeth. You still get the same cunning steel-toothed ring embedded in a composite support sandwich too and we didn’t notice any difference in durability or chain stiction compared to more costly options. The crank arms are nicely polished with a recessed logo panel that stops them looking tatty after the first ride which has been a previous Shimano issue. The arms are available in 170 or 175mm lengths with three different (52mm, 55mm and 56.5mm) chainline options. 

The 24mm steel axle still runs on the same proven durable bottom brackets with offside crank arm clamping and the whole set up feels solid underfoot, even on big travel bikes. The crank arms are solid though and while you’ll be getting similarly forged designs on other brands (often at a much higher price) SLX uses a 160g lighter Hollowtech II construction for only $10 more. 

Shifter 

The Deore shifter is indistinguishable from SLX (well, apart from the logo). It gets the same ribbed lever paddles for filthy conditions or sweaty finger grip and it comes in separate banded or I-Spec II integrated clamp formats. The shifting feel is a little lighter and more traditionally ‘Shimano’ than the deliberately clunkier feel of recent XT but shift speed and accuracy is excellent even under stress on an E-bike. 

Like SLX you can only downshift one gear at a time so you’ll need fast fingers accelerating out of a downhill corner, but you can still hook up into easier gears three at a time. You get a really good quality cable included too so shifting stays fresh for months.

Derailleur

We were properly shocked how good the new angular rear mech looked when we first saw it and it’s every bit as hench and ‘top-end’ in feel as it appears. Chunky upper sections and steel jockey wheel cages also mean it can take a beating without bending. The on/off clutch to reduce chain slap is also internally adjustable for tension if you’re really into tweaking your rear suspension or shifting feel. The only obvious cost concession (which it shares with SLX) are bushings rather than bearings in the jockey wheels but that hasn’t stopped them spinning freely after months of hard work. It’s no heavier than SLX either and the setup lines printed onto the cage remove the need for a separate SRAM style gear clearance gauge. 

Cassette 

While pricier Shimano cassettes get varying amounts of alloy cogs to save grams, Deore is an all-steel build that puts a fair amount of ballast onto your back wheel. You’ll also need a Microspline driver to fit it, but those are available for most wheels now. Steel means excellent durability though and the Hyperglide + tooth profiling means clean, concise shifting even on steep climbs with a Bosch motor heaving on the chain too. The 45 to 51 tooth transition is also a lot smoother and less cramp inducing than the 42-50 tooth gulf on SRAM NX.

Chain

While you can run any brand's 12-speed chain on Deore, you definitely get the best shift performance by matching Hyperglide + profiling on links and cassette teeth. Now that Shimano uses a splittable master link rather than a single-use snap off rivet there’s no reason not to go collar and cuffs either. We also find the sympathetic wear rates of cassettes, chainrings and chains mean they last longer as a set compared to mixed transmissions. 

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Verdict

The cranks are heavy on the scales and you’ll need fast fingers to keep up with rapid accelerations but otherwise, Shimano’s Deore is an absolutely outstanding groupset. Notice that we didn’t say budget groupset either, because while the killer price for performance ratio is obviously a big drawer, it never feels like a cheap option on the bike. We’ve been working it’s groovy shift paddles and stout looking rear mech on everything from hardcore hardtails to Bosch boosted full suspension e-bikes without a single glitch or issue and our long term set is proving as evergreen as previous Deore family setups. While we’ll be writing up in a separate review, here's a spoiler alert that the Deore M6120 four pot brakes are excellent too.

Tech Specs: Shimano Deore

• Cranks: 791g (175mm x 32T), £89.99 / $94.99
• Shifter: 131g (I-Spec II with cable), £32.99 / $31.99
• Derailleur: 320g, £59.99 / $54.99
• Cassette: 602g (10-51T), £89.99 / $91.99
• Chain: 280g, £24.99 / $23.99
• Total: 2101g, £297.95 / $297.95