“In the Blue Corner, with 12 speeds and weighing in at 1515 g, we have the Hammer from Japan, Shimano’s XTR M9100.” “In the Red Corner, also with 12 speeds and weighing in at 1510 g we have the German Engineered Hitman, SRAM’s X01 Eagle…Boxers ready? Fight!”

Shimano XTR M9100 | € 1,409 | SRAM X01 Eagle | € 1,385

Fanatical loyalism is rife in the world of drivetrains. Quotes like “Shimano is so reliable, SRAM is junk” or “Shimano is old school, SRAM is the king” bounce around every forum drivetrain discussion. Given that both drivetrains do exactly the same thing in an almost identical way, it’s strange to see such fiercely opposed opinions. Starting in the early days of mountain biking, Shimano enjoyed unchecked domination of the drivetrain market for decades. As cassettes gained extra sprockets slowly and methodically over the years, SRAM Eagle suddenly arrived and everything changed. With 12 speeds and a 10-50 tooth cassette, SRAM Eagle offered a range that instantly killed the need for a front derailleur on a mainstream trail bike. Shimano’s domination was in tatters. For a number of years, Shimano offered no counter – yes the XT cassette grew a little bigger, but it seemed like there was no fight left in the dog. Then into the ring, stepped Shimano’s new 12 speed XTR M9100.

The Shimano XTR M9100 in Detail


Price € 1,410
Weight 1,515 g
Info bike.shimano.com


The Shimano XTR M9100 cassette is even bigger than SRAM Eagle, boasting a 10-51T cassette, giving 10 % more range, and more importantly, giving more range above and below the current 11-46 T Shimano cassette
M9100 is a ground-up redesign, including a new MICRO SPLINE shimano freehub. Shimano’s new hubs feature its SCYLENCE technology, meaning the freehub runs totally silent – hikers beware
Shimano have focussed on even gear-steps and have switched to direct mount chainrings with narrow-wide tooth profiles to ensure chain retention
The 12 speed XTR M9100 rear derailleur features a more powerful RD+ friction clutch and larger 13 tooth jockey wheels to help keep the chain in place
Shimano now include a quick link chain adaptor – far easier to work with
Shimano XTR M9100 has the ergonomics dialled, the long triggers with rubber traction pads are sublime

The SRAM X01 Eagle in Detail


Price € 1,358
Weight 1,510 g
Info sram.com


The once groundbreaking 500% range is still huge. It’s all thanks to the dinner plate sized 10-50 tooth cassette.
SRAM’s top-of-the line trail/enduro groupset is X01 Eagle, targeted at the rider who values performance and durability over affordability.
The X01 Eagle derailleur features a stronger clutch and huge jockey wheels to stabilise the chain over rough ground
SRAM have proven the tenacity of their X-SYNC narrow-wide chainring teeth when it comes to hanging onto the chain
SRAM X01 Eagle features a beautiful carbon crank, saving weight. Crank boots come as standard to minimise pedal strike damage
The SRAM X01 Eagle shifter is neater and more stylish, but cannot match the ergonomics of the Shimano XTR M9100

The battle

Going toe-to-toe with the formidable SRAM X01 Eagle on price and target market, Shimano XTR M9100 is aimed at discerning trail riders who want the best-of-the-best. To find out which drivetrain is the king-of-the-ring, we have been putting both drivetrains to the test in our tough Scottish outdoor laboratory. Up- and downhill, through rain and shine, good technique and bad, we can guarantee that we haven’t been gentle. We ran both drivetrains in a 1x configuration with a 32 T chainring and no chain guide. It should be pointed out that if you want a 2X drivetrain then you can stop reading now, XTR M9100 is the only drivetrain for you, and is available in a huge number of configurations. But, if like most of us, you are looking for the ultimate 1X drivetrain, SRAM X01 Eagle has proven itself in our long-term reviews as an exemplorary performer. Let battle commence.

Shimano’s SCYLENCE technology freehub is a revelation. Hammering through the woods with just the growl from the tyres is a surreal experience, especially when you’re used to the maniacal howl of an expensive freehub.

Round 1: Chain retention

It’s a fact, SRAM Eagle killed the need for chain devices for all but the rowdiest of hooligans. SRAM’s X-SYNC 2 chainring with a narrow-wide profile hangs onto the chain tenaciously, and in over a year of riding, we only lost the chain a couple of times due to sticks and mud. Shimano XTR M9100 uses their new DIRECT CHAIN ENGAGEMENT+ which to our eyes, looks almost identical to SRAM’s tooth profile, and, as such, is unsurprisingly very effective. While we have not yet racked up a year of riding on Shimano XTR M9100, despite our best backpedaling, bad-language and idiotic-shifting we could not get the chain to jump off the chainring. Shimano’s XTR M9100 rear derailleur features a more powerful RD+ clutch, which holds the chain noticeably firmer and provides a silent ride, but more time will be needed to see if it loses its smoothness due to wear like the current M9000 group.

Round 2: Weight vs durability

In this battle of the heavyweights, it’s clear that both are anything but heavy. Weight loss has been aggressive and every component has been cut down to the lightest possible form – you would find more fat on a butcher’s apron. SRAM has the edge by a few grams mainly due to the lighter carbon X01 crank. SRAM”s one-piece 10-50 tooth cassette is also work of art, with a price to match, but any weight saving is negated by the heavier X01 Eagle derailleur. While having a disadvantage on paper, Shimano XTR M9100 has a lower unsprung mass (cassette + derailleur) and places more weight in the more robust crank where the extra grams can be beneficial. A carbon crank may save weight, but we do like to see aluminium used if not too heavy, we’ve never seen a snapped XTR aluminum crank arm, and still have some in service from the 1990’s. If you are a frequent pedal striker this may be worth some consideration. It’s too soon to comment on the durability of the XTR M9100 cassette, but our SRAM X01 Eagle cassette is proving exceptionally resilient.

Weight Casette Shifter Derailleur Crank (32 T) Chain Total
Shimano XTR M9100 363 g 122 g 252 g 540 g 238 g 1,515 g
SRAM X01 Eagle 355 g 125 g 282 g 484 g 264 g 1,519 g
Price Casette Shifter Derailleur Crank (32 T) Chain Total
Shimano XTR M9100 € 399.95 € 149.95 € 299.95 € 489.95 € 69.95 € 1409.75
SRAM X01 Eagle € 392.00 € 146.00 € 242.00 € 540.00 € 65.00 € 1385.00

Round 3: Gear Steps

When it was released, SRAM X01 Eagle redefined smooth shifting with even gear steps distributed through the mid-range. The sacrifice for that is a noticeable final jump onto the big 50 tooth chainring. Shimano’s XTR M9100 cassette features a larger range and moves the bigger steps between the 28 and 39 tooth sprocket. On the trail this means a smoother transition into the largest 51 tooth sprocket which feels more part of the usable range and less of an ‘emergency’ bail-out gear. However, there are some noticeable cadence changes lower in the block. Under load on short punchy climbs, when compared to SRAM X01 Eagle, Shimano XTR M9100 shifts faster and smoother on to its biggest sprockets for ‘last second’ panic gears. Which drivetrain you prefer will largely be determined by your riding style and terrain. Those who live on undulating terrain will love the sublime mid-gear spacing of SRAM X01 Eagle, while those who live in steep terrain with potent climbs will like the smoother cadence shifts in the final three ratios of Shimano XTR M9100. A close round and another draw.

Round 4: Service

There is no doubt that SRAM X01 Eagle is a superb drivetrain, but, like a supercar, it does need careful setup and maintenance to achieve the best performance. If the B-tension is set incorrectly, or the cable tension slips, the smooth performance starts to falter and ghost-shifts and hesitations can occur. In our tests, Shimano XTR M9100 requires a similar level of careful setup but in our tests it does operate more robustly when things are sub-optimal. During our three months of testing we did not have to reach for the toolbox once setup, even when we detuned the B-tension, the shifts were still smooth and precise. When it comes to setup and reliability, Shimano is the champion of fit-and-forget.

Round 5: Shifting

In our long term SRAM X01 Eagle review we have already proven the impressive shifting from SRAM, how does Shimano compare? Despite trying to avoid marketing hyperbole or inflammatory comments, we have to state that when it comes to shifting, Shimano XTR 9100 is also phenomenal. Even when shifting like an idiot, slamming up through the block under load, the derailleur mocked our futile attempts to break things, snicking through the gears with sewing-machine like precision. The shifting is crisp and beautifully light, with just enough resistance to provide sublime feedback. Going toe to toe with SRAMs X01 Eagle, Shimano’s new Instant Release mechanism snaps the gears into place under load marginally faster and smoother, especially in the biggest sprockets. Ergonomically, the triggers on the Shimano XTR 9100 shifter, with the long rubberised paddles are unbeatable, and being able to double shift down the block with one long press cannot be matched by SRAM. When it comes to shifting, Shimano XTR M9100 delivers its knockout punch.

While based on the same-old derailleur concept, both drivetrains show just how far technology has evolved, using cutting edge materials to deliver a huge range of gears.

A victory, but a hollow one

In this battle of the titans, both offer sublime performance, but there can only be one winner. Shimano has brought the fight back to SRAM’s doorstep, boasting lighter and more efficient shifting than SRAM X01 Eagle. With robust operation and superior ergonomics on the trail in our tests it’s the best drivetrain. However, currently, Shimano XTR M9100 has a weakness, an Achilles heel, and ultimately the victory is a hollow one. Bringing in a new standard in the form of the MICROSPLINE freehub was not an unexpected move – indeed SRAM did the same with their XD Driver – but with only a few manufacturers currently having compatible wheelsets, most riders looking to upgrade will likely already own an expensive wheelset that will now be incompatible. While more wheel brands are already following, we may not see a complete range of options until 12 speed and MICROSPLINE trickles down to the more market-friendly XT and SLX groupsets.

XTR M9100 takes a giant leap forward for Shimano, raising the bar in terms of shifting and ergonomics. However, MICROSPLINE takes a step backwards in terms of compatibility so it will take time for the market to catch up. We look forward to when the technology rolls down to SLX and XT level, and more wheel options become available. With SRAM’s Eagle eTap wireless surely about to enter the ring, the fight’s not over yet.


This article is from ENDURO issue #035

ENDURO Mountainbike Magazine is published in a digital app format in both English and German. Download the app for iOS or Android to read all articles on your tablet or smartphone. 100% free!

Words & Photos: Trev Worsey

About the author

Trev Worsey

Trevor loves adventure. Whisky, riding his bike and everything in between. Though he was born in England, he believes he should have been Scottish. Besides being accustomed to bad weather he's a specialist when it comes to steep and demanding trails. Once, he was in love with competition and raced in the early years of the EWS, but now, at 41-years-old, he no longer has anything to prove. Nonetheless, demonstrating that you can teach an old dog new tricks, he continues to hold his own against the wild and fearless youth. As a reminder of his new role as a father, the words “Think about Brook." (his son) are inscribed on his top tube as a gentle warning against unruly riding. Together with his young family and two crazy dogs, you will almost always find him outdoors. Whether it's teaching Brook to ride trails, hammering out gravel loops, surfing, skiing or canoeing, he’ll be there no matter the weather, like a true Scotsman.