20 Best Derailleur For Mountain Bike (Jan 2023 Update)

It's not the best derailleur made, but it served its purpose – it was a quick, effective, and most of all, inexpensive replacement for a broken unit. Cambria Bike was super helpful and did things they didn't have to do to win my meager business. Thanks, Cambria Bike!Stephen L.

I'm renovating an old Kona Lavadome and used this to replace the original Shimano rear. It does what you'd expect – easy to install and adjust. Smooth changes.Christopher H.

The Prime 9 is a good wide range drivetrain for less money. It works well when it works. I'm less than satisfied with the composite b-screw housing. I broke the first one I had trying to make the screw longer. Eventually I modified it to work. Then I destroyed the derailleur and needed a replacement. I have already acquired a longer b-screw so I don't begin on the wrong foot again!David

The price was very attractive but the quality was lacking in this product. One of the jockey wheels became disengaged while I was setting the derailleur. I was forced to remove the unit to put it back together. After repeated attempts to adjust the derailleur I gave up and installed a different unit.845bikerron

Best derailleur for old road bikes with semi-horizontal, forward facing dropouts. Old French, English, or Japanese 10/12 speed with a friction shifter? This is for you.Scott B.

This was the best item I have ever purchased from Halfords. the item was bought on the click and collect procedure of which I was able to collect my item within the hour of ordering it. I would recommend Halfords for any accessories you may need for any type of bicycle. If needed in a hurry they will even fit your part for you and have you back on the road the same day.Andy the bully pickford

Hi, I bought this as a replacement and so far so good. I did want to mention that while this is a replacement of the X7 AND X9 the quality is not the same as an X9 and only sort of on par with an X7. However it shifts fine and performs the same functions. As for the B-limit acre being pushed out or the quality of it I would mention that this derailleur was intended to be used in a 2x system (not that it won’t work well in a 1x) and so the max recommended cog seems to be 36T which is different from the stated maximum capacity. I have used this derailleur with both a 11-36T and a 11-42T (which is outside the recommendation) and with the 11-36T I barely had a need for the B-limit. With the 42T I only needed the screw turned halfway in and it seems to sit nicely against the stop. So unless you are running some giant cassette this derailleur wasn’t intended for I don’t see it being an issue however I’ve yet to do more than a few drops and some flat 180’s on the bike.Reindeer

I bought this to replace my x5 which died after a few hard treks. My bike is a 2014 rockhopper comp 29er. I ride hard and aggressive. At first, I thought the GX was an interesting design. A clutch derailleur, light, and it looks cool. But when I installed it, I could never get it to shift properly. I tried upgrading my shifter to teh GX shifter and although that helped, it didn't' solve the problem. Indexing was a mess. the derailleur is also very bulky, and sticks out a lot, getting hit quite often when trailing. Before returning this to mec, i shot SRAM a message asking for aid, since I was determined i was doing something wrong. They mentioned that the GX line up replaced both x7 and x9. Which means, it's something in between. When it did work, it was nice. light, crisp, quiet. But as an aggressive rider, I need reliability. I returned this and got a shimano SLX m675 shadow + and it has worked 100%. If you are a light rider, this can work for you. But if you're aggressive, don't bother. It will break. This is a budget derailleur, at a premium price. Best to stick with the x9 2.1 instead.rockh0pp3rslx

I got this to replace my busted Sram on the dh bike. This one is the lowest price one i could get, which is good, because you WILL destroy derailleurs over a long enough time. Unless you are a roadie pretending to be a mtn biker. Shifts fine, no noise, easy to set up. Works fine with the single chainring up front and 10 gear cassette. Loses a star because Sram just has to be special and not use hex fasteners like every other bike company. The adjustment screws on this take a very small philips head screwdriver, and have shallow slots ensuring that a reasonably small screwdriver slips just enough. Who does that?IAN

They keep asking me for a review so here it is. I bought some gears because the last lot got smashed. I had trouble installing them. I had to buy more equipment to fix it including a new chain and the tool to shorten the chain, which halfords didn't have which I had to get from another shop. In retrospect I wouldn't' have spent upwards of £60 on kids bike repairs I'd have bought a whole new bike instead. Bike repairs generally are a difficult economic prospect unless you've bought a £1000 bike. But the gears themselves are fine. They are gears.brokenkidsbike

I needed to buy a new rear derailleur after the rain cover of backpack, came off and got caught up in the old one! The Altus was a recommendation by the staff because of the sturdier cage. As a product designer I can see this is a solid piece of kit. Definitely surprised at how inexpensive this new set was (phew!) shifts positively and feels more reassuring.Andrew12789PO

Love these simple cheap derailleur's. Easy to set up you should not have to touch the A limit screw but the B limit will have to be moved if you are putting into a 7/8 speed this is the bottom of the two vertically aligned screws at the back of the mech. This does two things, stops the mech hitting the wheel and allows the mech to reach the largest gear. Probably the best upgrade you can do to a tourney gearset. After a short time the tourney's jump sprockets which I find irritating. Don't forget to change the cable inner at the same time. this is easy to do. often the shifter end of the cable is concealed, under the rubber grip (microshift) but I have never had to remove the shifter to change. If you don't know YouTube it! Have funkoor1958

Excellent replacement for my broken derailleur. Worth noting that the hanger doesn’t come in the box. This is a separate part & therefore at additional cost. Gears now work better than they ever have.Maz1234

I recently had this Mech fitted to my Carrera Sulcata by a local Bike Tech. They recommended it as previous owner had bodged the gears by fitting different brands and types, this sorted my gears out tremendously and haven’t experienced any gear slip on the road as yet which it’s mainly used for, still need to check out how it handles off-road but all in all for general use a decent productBrooksy21

Ended up snapping my deralieur and the hangar quite a few months back. Popped into halfords the other week to see how much a new derailieur would set me back and to my supprise they had the one that used to be on my bike and it was a lot cheaper than expected. Apart from forgetting to buy a new hangar for the derailieur, installation was very simple and was extremely easy to tune up the gears. Still isnt perfectly tuned but this isn’t a high-end product, nor do I know fully how to set up the derailieur tuning either, but regardless very easy and works very well. (Just want to point out that the only reason the last one broke was because I caught it in the spokes of my bike and the force on the chain ended up snapping it, wasn’t the product, but human error on my part).Alexxxx17462

Great derailleur with two minor issues. Functionally, the RD is excellent. It provides clean and crisp shifting through the cogs. It looks great on the bike tucked under the chainstays with the shadow technology. Now on to the gripes. 1. The number one gripe is that the barrel adjuster is absolute garbage. I was turning and turning and it wouldn't move. The adjustment collar is a crappy soft piece of plastic that would slip and slide around the nut. Looked on youtube and I found the solution was to replace the barrel adjuster with the 6800 barrel adjuster (part #: Y5YC98030). The 6800 design has a beefier hard plastic collar that has multiple engagement points with the nut. 2. The shift cable exit point goes RIGHT into the rear spokes! This made adjusting the derailleur prior to cutting the cable a pain in the butt. I had to awkwardly wrap and tape the cable around the chainstay so that the cable would not get caught in the rear wheel and potentially ripping something out.ERWEN

This review covers three products – Ultegra 8000 GS rear derailleur, SRAM 1170 11-36t cassette, and SRAM 1170 chain, because they all work together, and only a magician could tell you which one deserves more of the credit. I learned while training with a power meter for the Whistler Granfondo that low-cadence grinds up long hills reduces my speed and power towards the end of long, steep rides. My bike doesn’t have low enough gears for my 70 year old legs, so I needed a bailout low gear for the long hills. I bought a SRAM 11-36t 1170 cassette. My Ultegra 6800 derailleur wouldn’t accommodate it, so I used a “Wolf Link” to extend it to take the 36 tooth low gear. The shifting with the Wolf Link was OK, but nowhere near as good as my Ultegra 6800 derailleur with the Ultegra 11-32 cassette that came with my bike. Shimano says that the new Ultegra 8000GS rear derailleur (2018 version with medium length cage) will accommodate an 11-34t cassette, a 16t difference on the front derailleur, and a total of 39 t. I was aiming to use it with a 41t difference. So I bought the derailleur, installed it, and set it up for the big bailout gear. My chain was too short, of course, and MEC only had SRAM chains, so I bought the SRAM 1170 model. With these three items – the Ultegra 8000GS derailleur, the SRAM 1170 cassette, and the SRAM 1170 chain, the bike shifts BETTER than it did with the original equipment! And the drive train is nearly silent, in every gear. The Shimano stuff made noise when cross-chained (50t front, 32t rear). The SRAM makes no noise when cross chained, or anywhere in the shifting range. Cross chaining costs watts – it’s inefficient – but from time to time, you may need to do it in a pinch. The Ultegra 8000 derailleur is light, fast, easy to set up, and shifts consistently, up and down the 11-36 cassette. The SRAM 1170 chain was barely long enough – 114 links – to accommodate my 50t front chainring and my 36t big cassette sprocket. I don’t know if it would work for a 52-36. Together, they make a great combination that allows me to motor up very steep hills (18 to 20% grades) instead of getting off and walking. Don’t think it’s because my legs are old. Lots of people get off and walk on the 20% killer hill on the MEC Century ride out of Coquitlam. But not me! I’m delighted with the results.TheShovel74

Just upgraded the Pina Kobh from 10 to 11 speed Ultegra with the 10 speed cranks still in place. Still have the Dura-Ave C50 wheels, had a 11 spd 11-32 cassette machine out 1.85 mm at Lasco Concepts in Canada, so it fits on the shorter spindle. Works perfectly. This derailleur is smooth as glass. Great work by Sacramento Kinetic Cycles, too!friendsofarchimedes

Excellent replacement for my broken derailleur. Worth noting that the hanger doesn’t come in the box. This is a separate part & therefore at additional cost. Gears now work better than they ever have.Maz1234

I recently had this Mech fitted to my Carrera Sulcata by a local Bike Tech. They recommended it as previous owner had bodged the gears by fitting different brands and types, this sorted my gears out tremendously and haven’t experienced any gear slip on the road as yet which it’s mainly used for, still need to check out how it handles off-road but all in all for general use a decent productBrooksy21

Ended up snapping my deralieur and the hangar quite a few months back. Popped into halfords the other week to see how much a new derailieur would set me back and to my supprise they had the one that used to be on my bike and it was a lot cheaper than expected. Apart from forgetting to buy a new hangar for the derailieur, installation was very simple and was extremely easy to tune up the gears. Still isnt perfectly tuned but this isn’t a high-end product, nor do I know fully how to set up the derailieur tuning either, but regardless very easy and works very well. (Just want to point out that the only reason the last one broke was because I caught it in the spokes of my bike and the force on the chain ended up snapping it, wasn’t the product, but human error on my part).Alexxxx17462

Not as expensive as the XT mech but a lot better quality than the straight Deore version. Very happy with the price and speedy delivery.Richard A

I'm using this derailleur on my gravel bike instead of the more pricey GRX and, if you're into brisk riding over rutted terrain, I would absolutely recommend this (with a JTek shiftmate 8A). The only not excellent thing is: if you're using a 42 teeth largest sprocket the shift out of this gear is somewhat laborious. Consider using a 40 instead. This is not the case for a comparable, but more expensive, XT RD-M8000. ~~~ 3500 km update: I solved the issue shifting out of the 42 teeth sprocket by servicing (abundantly greasing) the clutch and reducing the preload on it –it is possible to do so: you have to open the casing. Still, behind the same JTek adapter and using the same R7000 STIs, this mech performs significantly less than the XT RD-M8000.Lorenzo Za.

Used this with 12 speed 10-45 cassette and xt m8100 shifter and I’m getting great shifting performance! The clutch works really well and I have no complaints after running this thing through the chunk for a year. Great budget option! And works with shimano 12 speed 10-45 cassette with 12 speed shifter!Johnny

Quick delivery and as well designed and produced as all Shimano gear is so it was easy to install and set up. Shimano website has full instructions if you haven't done it before. Having needed to replace it because the hanger arm (long cage) of the previous one was mangled when the chain jammed and pulled it up between the frame and wheel; consequently, it would be 5 star if it had been a little bit stronger to resist such damage. That is a trade off with a weight penalty that I would accept for my low-geared touring bike, which is where this model will mostly be used, so that I don't get stuck in the middle of nowhere.laser162939

Had to replace my old 105 rear derailleurs, fit perfectly, are a bit lighter, and have another cableway than the older. The best are the new limiter screws. Now you can see the screwsize and it's very clear which is for which limit.Holger J.

Works like a charm, able to fit a 34. New design incorporates a "Wolftooth" type hinge that seems weird, but works great. Easy set up. Too bad Shimano will not keep quality mechanical groupsets going forward, I think in the future many will have to settle for 105 (or lower) to get mechanical.J.L.

If you want simplicity and durability without breaking your wallet , this Shimano derailleur is it ! Incredible range and crisp shifting makes this Shimano rear derailleur a priceless component at the right price!Brian M.

So far, the gx deraileur has been great. This is actually my second as I sheared my first one into two pieces. The shear was after I got long dry grass stuck in a jockey wheel and was pedaling, it tweaked the deraileur. I then proceeded to try to finish the ride and had the deraileur grab a spoke in my lowest gear. I attribute the breaking as mainly my fault. Other than that, the gx has shifted great paired up to an 11-46 11 speed cassette. Way more reliable and user friendly than my old 2×10. I am running a narrow wide chain ring with out a guide and have yet to drop a chain. Time will tell with how the pins in the mechanism wear and if they develop slop. So far, I'm happy with the purchase.JOSH

I purchased this since I needed a long cage to run a super wide range cassette. It replaced my Force CX1 Rear derailleur which I was also very happy with, but was a mid cage. This derailleur weighs 10 grams more than the Force but who cares. It works absolutely fine, and I'm not sure why you'd choose the Force over this one unless you needed the Force branding. Paired with an 11-40T cassette, chain slap is a thing of the past, and riding without a front derailleur is very freeing. I can combine road and trails into one ride! Sold! PROS: Durable, Lightweight, Easy To Install, Attractive Design CONS: Limited Compatibility BEST USES: Road Biking, Casual Riding, Mountain Biking, UpgradeAaron

Excellent product; have had my old one in service for 5 years and it is still in great shape. Wanted a spare for when it actually needs replacement. Very rugged, smooth, reliable and dependable. Wonderful functionality and performance during climbing and descending the step terrains of the NS in Vancouver. The extra costs of a fancier and lighter models is not worth the price of 'admission'. Stay with this work-horse of the industry!milton

For the price point, this rear mech. is an easy performer good for bashing just about anywhere. Yes, the components are not GX or Eagle, but if your not trying to build the worlds next lightest mtb and you need a durable mech for some bashing…the NX'll do nicely. Paired with the 11 spd NX Shifter and 11 spd Chain, the system works flawlessly and smoothly, shifting well under load. The only downside I could find was that the out-of-the box tuning required a lot of micro adjustments to get just right due to the mech. construction. Plastic guide wheels and looser than GX bearings will probably be the first things needing replacing, but I've got some mud and sand to beat them up with till then. Happy for now!ryan1surfknots

It is the specified derailleur for the Haibike Nduro 8 and it seems to work well. it replace the original because the bike got caught in some weeds, bike maneuvered backward and something stuck in the jockey wheels cause the overextention of the unit and it was stuffed and locked up. could not fix it on ride. New works like a treat.Stephen D.

The NX derailleur falls short of of good for 2 main reasons. 1. On 3 NX derailleurs I have taken apart, the main hanger bolt & B-stop assembly is loose & rattles around because they all were missing the wave washer/O-ring to keep internal tension. This alone makes the derailleur Kmart level cheesy. An EASY fix for SRAM, and would not be more than 15 cents! The GX has it. 2. The pulleys do not have bearings. They are quite loose fitting bushings that induces excess slop in the drivetrain performance. Not the end of the world, but not something I could live with on a $3000+ bike. The GX pulleys have bearings. So, JENSON USA is not kidding when they say it’s for sub $1000 bikes. If you have a cheap bike, an apathetic tolerance to quality and a limited budget, this NX derailleur will be ok for you.MARC

Excellent replacement for my broken derailleur. Worth noting that the hanger doesn’t come in the box. This is a separate part & therefore at additional cost. Gears now work better than they ever have.Maz1234

I recently had this Mech fitted to my Carrera Sulcata by a local Bike Tech. They recommended it as previous owner had bodged the gears by fitting different brands and types, this sorted my gears out tremendously and haven’t experienced any gear slip on the road as yet which it’s mainly used for, still need to check out how it handles off-road but all in all for general use a decent productBrooksy21

Ended up snapping my deralieur and the hangar quite a few months back. Popped into halfords the other week to see how much a new derailieur would set me back and to my supprise they had the one that used to be on my bike and it was a lot cheaper than expected. Apart from forgetting to buy a new hangar for the derailieur, installation was very simple and was extremely easy to tune up the gears. Still isnt perfectly tuned but this isn’t a high-end product, nor do I know fully how to set up the derailieur tuning either, but regardless very easy and works very well. (Just want to point out that the only reason the last one broke was because I caught it in the spokes of my bike and the force on the chain ended up snapping it, wasn’t the product, but human error on my part).Alexxxx17462

Tight, light and always on form. Stands up to bad shift timing, and handles the wear very well. I’ve had another XTR derailleur in service for over 5 years now, still works flawlessly. GS cage for 1x setup.Todd

Awesome derailleur with the double shift capability and a clutch. Once you experience the double shift you’ll never go without. Yes I know the shifter.Piranha2

Long live Shimano 11 speed! While I find myself chasing cycling trends, I've also grown to appreciate technology that has proven itself. Shimano 11 speed is just that. The XTR derailleur is totally unnecessary when an SLX will just do. But it is a fine looking derailleur that doesn't hang down low like most 12 speeds. However, shifting performance isn't as smooth as 12 speed.Altaf

Came with my bike. One nice feature was the clutch thing that holds the derailleur open. General shift quality was good, maybe about the same as Deore or SLX. If you take the derailleur off for travel the washers and springs that fly everywhere are annoying. Much simpler with shimano. Today I was JRA (seriously) and my well adjusted derailleur just jumped into the spokes and exploded. Pretty annoying. Jockey wheel, spoke and outer-cage destroyed. The reason I will not by this ever again is that you can't buy a replacement outer-cage. What a SHRAM!Matt

The GX 12 speed derailleur is the workhorse of the SRAM lineup. It offers great shifting performance, at an affordable price. The NX and SX derailleurs leave some to be desired in quality and performance. The X01 derailleur is lighter, but much more expensive. I recommend pairing a GX derailleur, and an X01 shifter. This is the best value for performance.Matt M

Outstanding derailleur, solid shifts that are consistent and precise. WAY easier to adjust than the AXS. If you get something wrong, good luck getting it to run like butter again. It's like an old car vs a new car…you can work on the old one yourself, but you need special tools and technology to work on a new car – same with XO1 vs AXS editions of SRAM. I beat the brakes off my SRAM XO1 12-speed derailleur doing Enduros and it has never let me down. You can upgrade the pulleys and cage (out of the gate, or wait until you smash yours on a rock, like I did) to the ones from Garbaruk – they are outstanding for cassettes, pulleys/cage, etc and less pricey than equivalent from the original / SRAM stuff. The upgrades will make some minor, but noticable performance and efficiency improvements – plus they look sick, as they come in a bunch of different colors. Ride it til you smash it, then customize your whip…the derailleur will keep on shiftin' Unrelated – "Save Some Loot" tip: FYI – you can add this to your google search – try: 'part you want' + 'take offs' and you can often find brand new parts that came from open box or new bikes who upgraded (and the brand new factory/bike shop-installed parts (w/o any box of course) were 'taken off') – typically for 25% off, if you can find a vendor online or local bike shop that offers that – call and ask!snakechurch

I purchased this Deore 9-speed long cage derailleur to expand the gearing on my Litespeed 10-speed road bike from 11-28 to 11-34. The 9-speed mountain derailleurs have the same 1-to-1 pull ratio as the 10-speed road shifters and so the swap was easy and the shifts are flawless. I have one of these derailleurs on my 10-speed Lynskey Cooper as well and it works perfectly. A great and affordable way to increase one's gear range on a modern road bike.geobikee

My older mountain bike is a 9-speed and I wanted a upper tier Shimano long cage shifter. Hard to find but Erik's had it for a good price and I received it a couple of days before promised. Fit perfectly and shifts flawlessly.Rick

I prefer parts that are meant to work in harmony together and I instill this trust in Shimano components. I've used their groupos for decades and this derailleure is no exception. It is strong and shifts under load better than any of previous eras. I highly recommend it.Wallace

I was so excited to find this derailleur in the current parts shortage and not at a markup beyond MSRP. XTR is hard to beat, my shifting is incredibly smooth now. The purchase process was efficient and easy and shipping was fast and free.Benjamin K.

Was in the market for an XT mid cage 12 speed derailleur but they werent available anywhere so got the XTR instead. No regrets at this stage as this derailleur looks great and performs exceptionally well. Its fitted to my Canyon ebike and hasnt done much work so I cant comment on durability. Is it worth the price, time will tell.muka56

This is a nice replacement for the low end Shimano that my bike came with. It arrived very fast and went on easily, using th SHimano shifters nicely.Cycleguy

Needed to replace a well worn XTR RD on 1999 Stumpjumper with original 3×9 drive train. 34T cassette. This RD states 7/8 speed but has same pull ratio for 9 speed. Works great. Basically set up out of the box. M26 is about 65-g heavier. Shifting is now crisp and back to like new performance. Microshift product seems very well made. Steel cage and Alu/Delrin body. While it's basic, still does not feel cheap. Jockey wheels have bushings and ARE replaceable. Highly recommend if your not interested in bling and just want something that works at a great price.Chris

Le dérailleur Shimano XTR Di2 fonctionne parfaitement. D'une part le montage ne pose aucun problème et les réglages initiaux sont réduits à leur plus simple expression. Dans mon cas, il a suffit de régler la hauteur du galet de guidage. Je n'ai même pas eu à régler les butées ! Sinon, le fonctionnement est parfait; précis, instantané, puissant, il n'a jamais été pris en défaut.Decoster

Livraison un peu longue cause Covid Produit facile à monter Réglage très rapide des butées J'utilise la fonction Synchroshift qui permet d'avoir une seule commande au guidon avec une transmission 2 plateauxPIERRE T.

Montage et branchement d’une simplicité enfantine. Réglages; quels réglages ? Il suffit de vérifier que le galet de guidage soit à la bonne distance du grand pignon et c’est tout. C’est la seule vérification que j’ai effectué au remplacement de mon ancien XTR par ce Di2. Pour le reste, aucune intervention – butée haute ou basse, indexation… rien à faire. Au fonctionnement, c’est simplement exceptionnel. J’étais habitué à l’onctuosité et à la précision du XTR, auxquelles il faut désormais ajouter la puissance et la rapidité de passage des vitesses. Idem pour ce qui concerne le « synchroshift » qui gères très efficacement le passage du grand au petit plateau et inversement. Seule la manette droite est nécéssaire.Decoster