20 Best Derailleur For Mountain Bike (2023 Updated)

This GRX RD-RX400 rear derailleur is meant to work with Shimano road bike mechanical shifters that uses the long cable pull introduced with their 11-speed road groups, which means it works with 11-speed Dura-Ace/Ultegra/105 shifters, as well as the 10-speed Tiagra 4700 shifters and GRX “gravel” groups.

The great thing about the RD-RX400 is what Shimano calls an “SGS” long cage, which means you can use a very wide-range cassette like 11-40T on a double-crankset road bike with the above mentioned shifters.

The long cage gives the RD-RX400 enough capacity to accept the much longer chain needed to run the big cassette, which the shorter-cage standard Shimano road rear derailleurs cannot do. Shimano officially says the biggest cassette you can use with this rear derailleur is 11-36T, but plenty of people have successfully run an 11-40T cassette with it, some were even able to go to 11-42T.

To get the easier hill-climbing gears on your road bike with any of the above mentioned shifters, you will need this rear derailleur, a wide-range cassette (10- or 11-speed depending on what shifter you have), and a longer chain to accommodate the bigger cassette cogs.

I bought this rear derailleur to run a 10-speed 11-40T cassette on my road bike with Tiagra 4700 shifters and a 50/34T crankset, and it gives me a very easy hill-climbing gear combo of 34T front / 40T back = 0.

85 gear ratio. In comparison, climbing the same steep hill using a standard 11-28T cassette requires approximately 40% more effort (34T front / 28T back = 1. 21 gear ratio). The ability of this rear derailleur to run a wider-range cassette is an invaluable equalizer for those of us who don’t have diesel legs and need easier gears on steep hill climbs to keep up with stronger riders using standard gearing!.

This only has 20 miles so far, but works great, and we’ve had the M591 on our tandem for several years, so expect this to last just as well. I’ve overhauled the drivetrain on my wife’s 1990s Stumpjumper to get a lower and wider range of gears, so bought a new rear wheel and changed the bike from a 7 to 10 speed system.

Initially I had put on a 10-speed SRAM X5, but the lever refused to move it into the lowest gear. Turns out the ratio of lever movement to derailleur movement is different and the SRAM requires a matching SRAM lever.

We are running this 9-speed derailleur with a 10-speed Microshift flat bar road lever set on friction mode, and a 10-speed 11-36 cassette (note that the 10-speed version probably wouldn’t work either because Shimano changed the pull ratios).

It was easy to adjust and it hits all ten cogs great, so don’t listen to anyone who says you can’t friction shift a 10-speed system (or maybe direct them to my wife for help). The shadow design is pretty cool, with the pull mechanism tucked in behind the cassette cogs.

I actually purchased this as a spare part. I converted an old TREK Pilot 27 spd triple chain ring bike to a 22 spd double chain ring bike. Stripped the bike down to the frame. Installed all new Ultegra components, including bottom bracket and crank set.

I wanted to run an 11/34 cassette on the rear with 34/50 on the front. This long cage derailleur allowed me to use that rear cassette. The build went great. I’ve ridden the bike 1000 miles so far this summer.

Shifts smooth and reliably. I want to keep it working that way so I thought I’d pick up a spare at a good price. This fit the bill.

This is a great shifter and I’m happy with the performance. However, SRAM includes the absolute minimum cable and housing. With a large frame gravel bike and full length housing run, I needed to buy a new shifter cable, new brake cable, and new run of housing to use this.

The housing is just two small segments, and the inner wires for shifting and brakes are both too short to reach the mech/calipers. It’s probably plenty for a normal road bike without full length housing and short chainstays, but if you’re riding a bigger bike might as well add a cable kit to your order.

I bought this to build up an S-Works Aethos frame, where the other components fitted were SRAM Force AXS (sourced from a previous bike running 1x). Living in Devon, I need a 2x setup, so purchased the Red front derailleur as I couldn’t get hold of a Force.

The shifting is excellent, although it has thrown the chain off the big ring, moving from the small ring a few times, but this will just require a minor adjustment. There is zero chain rub even when cross-chaining (I know I shouldn’t do it)! Links flawlessly to the AXS app on my phone, which updates firmware (when necessary) and tells me how much battery life is left.

This was bought to make up a full AXS groupset (mix of Force and Rival; by going round about 8 retailers, I sourced all the components). The Rival rear mech seems to work just as well as the Force equivalent and the weight difference is trivial (less than 30g).

It’s also got a 36T capacity, which would make it useful as a gravel or all road option. Like all AXS stuff, it’s easy to install and set up, and the app is intuitive. I’d still opt for the Force crankset (the weight difference is appreciable) and shifters (if you want blips) but otherwise, Rival is superb stuff and actually pretty good value.

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!.

I am absolutely in love with this setup. The shifting is instant, silent, and super crisp. I always hated my mechanical setup, always having to adjust the cable tension and I could never quite get it right.

I felt like me previous setup was always missing shifts. Setup was insanely easy. I followed the instructions, set my limits, did a couple micro adjustments, and it’s amazing. Took maybe 30 minutes to install.

I’m no drivetrain expert, but I found the setup to be pretty smooth with basic mechanic skills. Very plug and play. It does take a little getting use to the new shifter. I do really like it, it’s just a little different ergonomically.

Not in a bad way, just a totally different feeling. Took a little tweaking to get right, but now I find myself loving it. I typically just rest my thumb on it comfortably while I ride. It comes with a really nice little multi-tool, I took that along on my first ride and spent a little time adjusting the shifter location.

Super easy. The battery is great. rarely have to charge it. I may end up buying a spare just to keep in the car or gear bag, but I don’t feel it’s really necessary. Might just be nice to have a backup.

If you’re on the fence, I highly recommend it. If you’re tired of your mechanical setup like I was, you’ll be stoked on the upgrade.

My son bought the AXS and loved everything about it for the FIRST YEAR. In fact, he would have given it similar reviews found on this page. Then, at an enduro at Silver Mountain in Kellog, ID it started to lose connectivity between the shifter and the derailleur.

We discovered that the plastic on the battery had worn down so the fit was no longer tight enough to keep connectivity. He was lucky enough to borrow a battery from a fellow rider and finish the enduro.

A week later, after purchasing a new battery, he unfortunately snapped his chain during a ride. After purchasing a new chain, we found that the derailleur no longer worked. We took it to our local mechanic who said it was broken and needed to be serviced, but when I called SRAM they said that the AXS is not serviceable.

When I told the customer service rep that my kid was really bummed to have worked to pay off the AXS upgrade and then just a little over a year later have to purchase a mechanical derailleur and shifter for another $300, he simply retorted, “biking isn’t cheap.

” I agree it’s not cheap. However, maybe SRAM and other developers should consider that when a new product is 3 to 4 times more expensive than the mechanical derailleur, they should build a product with serviceable/replaceable parts.

So, be aware that when or if something goes wrong with this system, you just have to buy another one. IF YOU RIDE A LOT, think about the cost of replacing this derailleur every year or two compared to the cost of a mechanical derailleur.

We will not buyer another AXS at this price point.

I started off with NX Eagle, GX derailleur, NX chain, NX Eagle shifter. I had ghost shifting, constant cleaning and re-alignment. ADVICE: chuck them in the bin or don’t buy a bike with them. I then went to GX Eagle cassette 10-52, GX derailleur, X01 chain, X01 shifter.

Better, much better – but still no where near as good as AXS. Honestly, I was about to jump over to Shimano. I’m now running GX Eagle cassette 10-52, X01 chain, AXS GX derailleur. Once the AXS Eagle was aligned it perfectly shifted, reliably and predictably.

Also, I think it might be shifting that little bit quicker which is noticeable on pinch climbs. Rapid up shifting is good – I have it set to do 3 at a time. What it doesn’t like is rapid downshifting into gears 1 and 2; this is exacerbated under load.

But once you know that, you configure to drop 3 (or 2) at a time by holding the downshift button. Then increment 1 at a time in the low gears. What I wish it could do is have the ability to configure a rapid downshift to a gear of your choice.

So if you were in 10, you could hold shifter button and it would rapid downshift to gear 3 and then increment by 1 gear at a time down to 2 and 1 (but there’s only options to rapid down or up shift in increments of 2, 3, everything or off.

This could easily be integrated into firmware. ) AND last of all, when you move the bike for storage or transport, you can accidentally bump the shifter and it will change gears without you realising.

But you get used to it and it’s not a biggy. Also, I’ve charged it once since buying it weeks ago. I better go and check/charge it ;P.

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!.

I bought this derailleur as an upgrade from a Shimano ZEE derailleur that fell apart from heavy use. The Saint deraileur is designed for for professional racing. Just by inspecting it that you can clearly see it top spec equipment.

There is a rubber bumper stop for the tension adjustment screw. Theres an additional link brace/skid plate for reinforcment. The pully cogs have ball bearings. And the shadow clutch system works perfectly.

Everything about it is one step above the ZEE derailleur. I think the best part of this derailleur is the rubber bumper stop. Lets face it, when you ride DH fast, most likely your in your highest gear and your mech is slapping agaist the tension adjustment stop.

This is one of the things that failed on my ZEE mech. But with a rubber bumper to take that shock away. Nothing gets damaged and its super silent. It’s a great derailleur!.

Amazing quality, coming off of a xx1 eagle I find that there is something special about the Saint drivetrain. Both are excellent systems but I feel I should have started with the Saint. As always excellent prices and speedy delivery are the norm at Jenson.

Saint derailleurs are pretty much my go to. I usually set these up as a 7 speed with a cassette block on my DH bike. This year I actually used it in conjunction with E13’s TRS carbon wheels with integrated 7 speed cassette.

The derailleur works flawlessly. Just screw the low limit screw all the way in and it is good to go. Furthermore. it is nearly 1/2 the price of the equivalent Sram offering. which. for Downhill. stings less when you roast a rear derailleur.

I had shifting problems with my existing Sram NX drivetrain. I had to decide whether to move up in price to a GX, switch over to Shimano, or go down in price to Microshift/Box. The easiest and cheapest and best reviewed was Microshift.

I did not have to change the cassette freebody since I was already running the HG driver. So far the whole Microshift drivetrain has worked flawlessly. No dropped chains or nasty noises. I also did not have too much difficulty with the reduced granny gear going from 50-tooth NX to the 48-tooth Microshift.

I purchased a bike that came with this derailleur stock on it and had nothing but issues. I owned the bike for 3 days and took it to four different bike shops to have this serviced. The derailleur could not maintain the proper tension, causing the chain to go all over the place while I was riding.

I would get the tension adjusted and within another hour or two of riding time it would happen again. The place I purchased it from finally just said the issues were just due to the quality of components so I returned it.

I won’t ever try another micro shift product again.

Haven’t tested long term durability yet. However, initial set up and first few rides are impressive. Followed the PDF instructions I found online and set up / tuning was a breeze. Light and crisp, hits the right gears on the first try, clutch mechanism seems to work well.

Set up with an 11-42t cassette and Trail Trigger Pro shifter and seems just as good as my SLX 11 speed. Very happy. And I like not having an ‘S’ brand on my bike.

I read numerous reviews from reputable publications about how good the new Deore 12 speed is; all of which were right. I’ve been riding XT/XTR 10 speed for the past 11 years, finally upgraded to a larger (51t) cassette and needed a derailleur to handle the gigantic “pie plate” cog.

I’m still using my XT 10 speed shifter and this 12 speed mech works perfectly fine (with shimano, you can use a higher speed derailleur with a lower speed shifter, but not vice versa). Super crisp and predictable shifting on par with the upper level Shimano components, AND IT’S CLUTCHED!.

This is a case in which “trickle down” actually works, I can’t recommend this enough, especially if you’re on a budget. If you’re a weight weenie or refuse to ride anything less than XT/XTR, skip this and spend the extra cash.

Weight is the only thing you’ll save, performance is the same. (Oh, and SLX is only a couple grams lighter than Deore. Weight savings of any significance are found in XT/XTR).

I have been running this since summer 2020 and it still performs flawlessly. No tuneups been needed in that time except maybe a couple clicks on the shifter’s barrel adjuster. I paired it with the XT shifter like some of the other commenters here since Shimano’s 12 speed drivetrain components are interoperable from Deore all the way up to XTR.

I have the 10-45 tooth cassette and realistically I would have been equally happy with the 11-46 range on Shimano’s 11 speed system because I usually find myself shifting 2 or 3 gears at a time (which, of course, this derailleur can handle easily).

The shipping was fast and accurate. My derailleur arrived undamaged and we’ll packaged. Much appreciated EVO! The XT Derailleur is a real champ. I paired it with my Shimano Deore shifters and it works very well with the Deore system.

The shifting is noticably faster than Deore and SLX. Solid upgrade worth the money for XC Racing!.

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.

Put this on a 2×10 bike packing build with bar end shifters and a 12×30 Ultegra cassette I had in the parts bin. Shifts crisply and accurately. Finish is not as good as Shimano, but functionality is on a par with older Tiagra/Ultegra —smooth and accurate.

I like the black cage, which is different from Shimano.

Excellent derailleur. It can pick up a 34T cog with ease. It is on a short coupled bike that runs a 53/39 front chain ring set and a 11-34T 8 speed rear cluster. While it can’t take the combined 53 to 34 cross and tooth count, it gets ALL the other combinations.

It would be a total dream on a normal road bike that was not built to climb, and is wonderful even in this demanding situation. It has been tried with both Shimano and microShift clusters, using both 8 speed and 9 speed chains.

I use microShift front brake lever/shift lever combo system that works flawlessly. The Shimano cluster shifts just fine, even with the wide range hop on the last shift. The microShift cluster has a more uniform spread of tooth count and shifts very smoothly.

Wonderful product. Slightly lighter than Shimano and works as well or better in every respect.

I’ve been using this rear derailleur on one of my bikes for the last couple of years and have been impressed with how smoothly it shifts, the ability to shift under load, and the two-cog jump with a single shift.

So when I was assembling components for my latest build (2022 Spot Rocker) I chose to go with the XT M8100 RD and shifter, XTR cassette and chain, with an Absolute Black 32T oval chainring. It is an amazingly smooth, quiet, and efficient drivetrain.

Arrived in excellent condition, exactly as photo portrayed. The product appeared durable and well manufactured. My mistake was that I did not recognize this is a Direct Mount derailleur, meaning it attaches directly to a flat mount on the bike post, which my bike does not have.

I am writing just so others will not make my mistake. If your old derailleur is mounted with a circular clamp, this item will not work for you either.

I wanted to upgrade an old Specialized Hard Rock frame I had. I was looking for solid but reasonable cost components. After researching I settled on SLX components. I purchased all of the components (front and rear derailleurs, crankset, BB, cassette and chain) from Jenson.

I had some questions and chatted with their associate and got excellent advise. Everything fit my bike perfectly. The quality is excellent and the ride is great. After a basic setup and tune on the stand I took the bike out and it performed perfectly.

Shifter for rear derailleur was a bit tricky to get it to switch to 9 positions but once I figured that out it worked perfectly. My only beef with Shimano in their lineup is the lack of support for integrated brake levers for non-disc brakes.

Since I was repurposing an older frame without frame mounting points for calipers I had to go with Tektro break levers. Again, chatted with Jenson and got great advise. They fit well and work beautify but would have been easier if Shimano had matching set.

I also got all the stuff on a Black Friday sale so it was a steal. PROS: Durable, Easy To Install.

Simple mounting instructions. One and done, works great. Mount it forget it. Realy useful with going to a double chain ring. With the amount of old school trails. Not so much flow that so many bikes are spec’d for these days.

Great upgrade for serious climbing.

I replaced a Shimano Tourney 7 speed derailleur with the Microshift R9 unit. It was easy to install and set up and works much smoother than the unit it replaced. It is also more solidly built with fewer plastic bits than the Shimano unit.

perfect drop-in replacement for an aging derailleur…indexed perfectly, installed in minutes. You could spend more but this was just I needed for an indoor trainer. You see them on big name frames, alongside the better known names.

I took my bike into Sigma Sports for a service. I had previously taken it to a different shop and the work was not satisfactory. Sigma sports identified the problem immediately, installed the new kit I needed, took the bike out for multiple test rides to ensure they had fixed the problem, and called me repeatedly to tell me what they were doing and how they were getting on.

I’ve got my bike back and it feels like I am riding a brand-new bike. I cannot speak more highly of Sigma sports.

Smooth action, precise shifting. Been running one on my Cervelo R3 with 53-34 front rings and 11×30 cassette with no problems. Had it on about 4yrs, have done quite a few Hill repeats near my house with no issues.

Answer: nothing but perfection. And the 9150 RD delivers. Dura Ace Di2 may be a costly proposition, but it IS state of the art. Form may be up to debate – function and quality are not. There is a reason most UCI WorldTour pro teams use it.

Put this one on my Bowman Palace:R, with full 9150 setup (+Shimano Powermeter), a set of trusty Mavic CCU and a Pro Vibe Carbon Di2 finishing kit with a saddle by Jure Berk. 15. 1 lbs. ready to race.

The whole package rides flawless, and electronic shifting sure has it’s part in it. I consider myself a traditionalist and resisted the push towards electronic shifting for years. But once you experience the difference, there is no way back.

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).

I learned after purchasing it that these derailleurs have problems with the “Type 2. 1 roller bearing clutch” not working properly, or at all. The one I bought had a clutch that wasn’t working at all.

Older versions were user adjustable, but the Type 2. 1 is pinned in place at the factory and is non-adjustable. Fortunately, with a bit of effort and a minor modification. the pin can be removed and the clutch can be adjusted to work properly.

Mine now works fine. Search for “modify SRAM type 2. 1 clutch” and read the Pinkbike forum article for instructions. As with other clutch-equipped derailleurs, shifting to larger cogs is stiffer and a bit louder, but works well.

Chain slap is virtually eliminated. Overall, I’m quite happy with it.

After replacing worn out grip shifts (20 y. o. ) with sram mrx shifters i got a different wheelset with 8sp freehub. On this i put a 12-26 8sp sram cassette intending to just use 7 gears with the existing shimano rd for the time being.

I was thinking about trigger shifters when i picked up an 8sp sram 3. 0 comp gripshift. The big glitch was forgetting to check if the shimano rd was compatible with the comp shifter. NO, and props to the old shimano rd which spun into a knot, but didn’t break.

That’s where the sram x. 3 rd comes into play. Out of the box it looks sort of cheesy, but i think that was because it was so clean. It was so easy to install and set up. The cable adjustment is at the shifter, not derailleur, so you can ride and fine tune at the same time.

And, less cable is needed vs Shimano so I didn’t have to get a new cable/housing. Bonus. Bottom line it shifts flawlessly and that’s what it is there for.

This was chosen as an upgrade replacement for a worn out XT derailleur on my downhill bike because of claims of it being a durable, the price, and the short cage. It’s on a mutt drivetrain with a mix of 9 and 10 speed components and works seamlessly with everything so far.

Installation was simple and straightforward. My only negative comment is that the cable linkage is dangerously close to the spokes. It’s kind of a funky design but hasn’t caused any problems as of yet.

Perfect replacement/upgrade for my DH bike. I was upgrading from old an old SRAM X9 setup, and the Zee feels so much better in every way. The short cage gives me the clearance I need to not worry about snags, and the clutch keeps the chain tight for consistent shifting and no noise from chain slap.

I paired this with a Saint shifter, and I couldn’t be happier. Plus, replacing a smashed Zee derailleur is cheaper than replacing a Saint one!.

I used this derailleur to switch my bike from 3×8 to 1×10. This thing is pretty amazing. The installation was a breeze and after setting it up, it shifts buttery smooth. It also has a clutch system which keeps tension on the chain so there is minimal to no chain slap.

If you are switching to 1×10 or are just looking for a quality 10 speed derailleur at an awesome price, this is it. I cant speak to durability yet since it’s pretty new but I have not noticed anything to suggest that it wont last a long time.

Shimano is a proven and reputable company and this is just another great product. I highly recommend it along with the matching ZEE 10 speed shifter.