Shimano XT RD-M8100 12 Speed Rear Derailleur - Long
The Shimano XT M8100 series of derailleurs brings a new level of drivetrain silence thank to decreased tension in the low gear position and an added bumper on the pulley cage. Larger 13T pulleys increase efficiency and chain management while compatibility with SHIMANO's new 12-speed cassettes boosts range. Features: Fast and precise shifting performance optimized to take on any trail. Silent drivetrain in all gear positions. Stable drivetrain on rough terrain. Faster and shockless shifting. Low-profile design. Wide range 12-speed drivetrain with low sprocket combination -10-51T. Decreased rear derailleur and chain tension in low gear. New bumper added to rear derailleur pulley cage. Bigger 13T pulley.
The Shimano XT M8100 series of derailleurs brings a new level of drivetrain silence thank to decreased tension in the low gear position and an added bumper on the pulley cage. Larger 13T pulleys increase efficiency and chain management while compatibility with SHIMANO's new 12-speed cassettes boosts range. Features: Fast and precise shifting performance optimized to take on any trail. Silent drivetrain in all gear positions. Stable drivetrain on rough terrain. Faster and shockless shifting. Low-profile design. Wide range 12-speed drivetrain with low sprocket combination -10-51T. Decreased rear derailleur and chain tension in low gear. New bumper added to rear derailleur pulley cage. Bigger 13T pulley.
The Shimano XT M8100 series of derailleurs brings a new level of drivetrain silence thank to decreased tension in the low gear position and an added bumper on the pulley cage. Larger 13T pulleys increase efficiency and chain management while compatibility with SHIMANO's new 12-speed cassettes boosts range. Features: Fast and precise shifting performance optimized to take on any trail. Silent drivetrain in all gear positions. Stable drivetrain on rough terrain. Faster and shockless shifting. Low-profile design. Wide range 12-speed drivetrain with low sprocket combination -10-51T. Decreased rear derailleur and chain tension in low gear. New bumper added to rear derailleur pulley cage. Bigger 13T pulley.
The Shimano XT M8100 series of derailleurs brings a new level of drivetrain silence thank to decreased tension in the low gear position and an added bumper on the pulley cage. Larger 13T pulleys increase efficiency and chain management while compatibility with SHIMANO's new 12-speed cassettes boosts range. Features: Fast and precise shifting performance optimized to take on any trail. Silent drivetrain in all gear positions. Stable drivetrain on rough terrain. Faster and shockless shifting. Low-profile design. Wide range 12-speed drivetrain with low sprocket combination -10-51T. Decreased rear derailleur and chain tension in low gear. New bumper added to rear derailleur pulley cage. Bigger 13T pulley.
in 31 offers
The lowest price for Shimano XT RD-M8100 12 Speed Rear Derailleur - Long right now is $49.24 at AliExpress.com - AliExpress-226247430, compared across 19 retailers.
The all-time low was $35.79 on 13 Mar 2026 — today's price is 38% above the lowest ever. It has been notably cheaper before — worth setting a price alert.
Prices last updated 10 June 2026.
Last updated at 10/06/2026 11:42:26
SHIMANO XT RD-M8100-SGS RD-M8120-SGS 12-Speed Rear Derailleur, Long Cage, Black
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originally posted on jensonusa.com
The best of the best. I have broken 4 XTR derailleurs, and numerous Sram derailleurs, but only one XT derailleur in over 35 years. Lighter than most, stronger than all I have used. Easy and accurate adjustments, plus worldwide recognition of Shimano's quality. They have always been a bit too price heavy, but the lower tier derailleurs just don't hold adjustments as well. I ride hard and frequently shift under load, what ever is required of the changing terrain. If you ride gravel you probably don't need this, otherwise….buy it.
originally posted on jensonusa.com
Excellent derailleur. Accidentally smashed it into a concrete wall doing jibs and it still works like new despite the self inflicted scratches. Shifting got a little slow after a heavy 4 months of use but I simply re-greased the clutch and it shifts like new. Overall performance is shift and crisp. I've never dropped a chain yet. I'm using this on my bruiser enduro bike and used to drop chains and break derailleurs like crazy with SRAM. To the point where I bit the bullet and changed the whole drivetrain to Shimano. I have not been disappointed at all.
originally posted on jensonusa.com
I purchased the NINER RIP 9 RDO XT M8100 JENSON USA EXCLUSIVE BUILD and took delivery in March 2020. After a couple of months and low milage on my NINER RIP 9 RDO XT M8100 JENSON USA EXCLUSIVE BUILD, as I shifted into smaller cogs, the chain drooped down towards the ground. The derailleur cage was still in its extending position from being in larger cogs. This is a well know problem! You can google "Shimano XT 8100 – Arising Issue" and find more on crankjoy.While the Failed Clutch in the Shimano XT 8100 Rear DERAILLEUR has been very disappointing, what has been even worse is the support I received from Jenson. Lack of response, month's of waiting. I pointed out the know problem to Jenson support right from the beginning (as covered in the article), yet that have ... MoreI purchased the NINER RIP 9 RDO XT M8100 JENSON USA EXCLUSIVE BUILD and took delivery in March 2020. After a couple of months and low milage on my NINER RIP 9 RDO XT M8100 JENSON USA EXCLUSIVE BUILD, as I shifted into smaller cogs, the chain drooped down towards the ground. The derailleur cage was still in its extending position from being in larger cogs. This is a well know problem! You can google "Shimano XT 8100 – Arising Issue" and find more on crankjoy.While the Failed Clutch in the Shimano XT 8100 Rear DERAILLEUR has been very disappointing, what has been even worse is the support I received from Jenson. Lack of response, month's of waiting. I pointed out the know problem to Jenson support right from the beginning (as covered in the article), yet that have been completely unable to ship me a replacement in a timely mannor. The failed derailluer was delivered to Jenson on 6/12/2020 and I'm still waiting! I hope to MTB again before the summer is over.
| Length | 20 centimetres |
| Sport | Cycling |
| Included Components | Rear Derailleur |
| Product dimensions | 17.78 x 17.78 x 12.7 cm; 413 Grams |
| Is discontinued by manufacturer | No |
SHIMANO XT RD-M8100-SGS RD-M8120-SGS 12-Speed Rear Derailleur, Long Cage, Black
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
Shimano DEORE XT M8100 Groupset Mountain Bike Groupset 1x12-Speed original RD M8100 Rear Derailleur
Delivery $63.39
SHIMANO DEORE XT M8100 M8120 SGS Rear Derailleur 12v 2V Shifter Lever MTB Mountain Bike SHADOW RD
Free delivery
SHIMANO DEORE XT M8100 SGS Rear Derailleur RD-M8100 Shifter Lever 12v 2V MTB Mountain Bike SHADOW
Free delivery
SHIMANO DEORE XT RD M8100 M8120 Rear Derailleurs Mountain Bike M8100 SGS MTB Derailleurs 12-Speed
Free delivery
The best of the best. I have broken 4 XTR derailleurs, and numerous Sram derailleurs, but only one XT derailleur in over 35 years. Lighter than most, stronger than all I have used. Easy and accurate adjustments, plus worldwide recognition of Shimano's quality. They have always been a bit too price heavy, but the lower tier derailleurs just don't hold adjustments as well. I ride hard and frequently shift under load, what ever is required of the changing terrain. If you ride gravel you probably don't need this, otherwise….buy it.
Excellent derailleur. Accidentally smashed it into a concrete wall doing jibs and it still works like new despite the self inflicted scratches. Shifting got a little slow after a heavy 4 months of use but I simply re-greased the clutch and it shifts like new. Overall performance is shift and crisp. I've never dropped a chain yet. I'm using this on my bruiser enduro bike and used to drop chains and break derailleurs like crazy with SRAM. To the point where I bit the bullet and changed the whole drivetrain to Shimano. I have not been disappointed at all.
I purchased the NINER RIP 9 RDO XT M8100 JENSON USA EXCLUSIVE BUILD and took delivery in March 2020. After a couple of months and low milage on my NINER RIP 9 RDO XT M8100 JENSON USA EXCLUSIVE BUILD, as I shifted into smaller cogs, the chain drooped down towards the ground. The derailleur cage was still in its extending position from being in larger cogs. This is a well know problem! You can google "Shimano XT 8100 – Arising Issue" and find more on crankjoy.While the Failed Clutch in the Shimano XT 8100 Rear DERAILLEUR has been very disappointing, what has been even worse is the support I received from Jenson. Lack of response, month's of waiting. I pointed out the know problem to Jenson support right from the beginning (as covered in the article), yet that have ... MoreI purchased the NINER RIP 9 RDO XT M8100 JENSON USA EXCLUSIVE BUILD and took delivery in March 2020. After a couple of months and low milage on my NINER RIP 9 RDO XT M8100 JENSON USA EXCLUSIVE BUILD, as I shifted into smaller cogs, the chain drooped down towards the ground. The derailleur cage was still in its extending position from being in larger cogs. This is a well know problem! You can google "Shimano XT 8100 – Arising Issue" and find more on crankjoy.While the Failed Clutch in the Shimano XT 8100 Rear DERAILLEUR has been very disappointing, what has been even worse is the support I received from Jenson. Lack of response, month's of waiting. I pointed out the know problem to Jenson support right from the beginning (as covered in the article), yet that have been completely unable to ship me a replacement in a timely mannor. The failed derailluer was delivered to Jenson on 6/12/2020 and I'm still waiting! I hope to MTB again before the summer is over.
Replaced a brand new M6100 rear derailleur in favor of one of these Shimano XT M8100's. I wasnt sure I'd see much performance gain, and was more focused on some weight savings, which is pretty significant. On my digital scale the M6100 weighed in at 354g , and the XT 8100 weighed 281g. So a nice win there. That wasn't all though, this derailleur in combination with the matching shifter was a very noticeable difference. Performance across Shimano's 12spd range is very similar, but the XT shifter/derailleur combo provides a much more crisp shift, with a much more refined feel. I was actually blown away, because of how good the M6100 was initially, and how the XT 8100 is just that much better all around. Hopefully no clutch issues down the road, as I've heard this can ... MoreReplaced a brand new M6100 rear derailleur in favor of one of these Shimano XT M8100's. I wasnt sure I'd see much performance gain, and was more focused on some weight savings, which is pretty significant. On my digital scale the M6100 weighed in at 354g , and the XT 8100 weighed 281g. So a nice win there. That wasn't all though, this derailleur in combination with the matching shifter was a very noticeable difference. Performance across Shimano's 12spd range is very similar, but the XT shifter/derailleur combo provides a much more crisp shift, with a much more refined feel. I was actually blown away, because of how good the M6100 was initially, and how the XT 8100 is just that much better all around. Hopefully no clutch issues down the road, as I've heard this can be an issue, but my feeling is it has to do with setup, and bike, but only time will tell. So far, it's amazing!
Shifts well. I’ve used it for several months and it’s been solid. Bent the hanger and somehow bent an adjustment screw both were replaced and it works fine. Using with gx cassette as I switch from gx. Doesn’t stick out as far as gx. Some say cable routing on gx is more efficient but it hasn’t caused me any trouble.
I have used the Shimano XT rear derailleurs for several years now. I have only had one derailleur that had a slight problem. Where the clutch mechanism got hung up some how and let the chain droop. I took it to Jensons and they said they would order a new one. Shaggy who was working the counter took it to the back to let the mechanic look at it. After a few minutes he brought it back and said to try it, as It seemed to be working. He said that if it works go ahead and use it until the replacement arrives. It has worked flawlessly since . I received the replacement and changed it out with no problems what so ever. With the positive record I've had with these derailleurs . I will continue to use them and more than likey be happy with the results.
I bought this product to be installed with the recommended 12 speed 10-51 teeth cassette from shimano. It works fine and shifting is fine through all gears. The difficult task was to try to manage and find the proper length of the new chain as it was installed on a Surly Disc Trucker. The B-screw adjusting precisely the distance between the cassette tooth and guide pulley was set using an approximate 5 mm distance between the 10 tooth cassette and guide pulley. The use of the drawn line at the back of the frame of the derailleur beside the pulley was useless and impossible to use. I thought this may have been related to the type of bike i have setup : Surly disc Trucker with a single plateau of 36 cogs at the front.
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.
I love XT parts because of the quality and durability. This is another win for Shimano great parts and fast shipping !!! Very satisfied !! I would recommend Shimano parts to anyone that loves to get out and ride trails.!!
Just installed this on my 2018 stumpjumper as part of an upgrade to 12 speed. The shifting is amazing on this. Smooth and accurate even when shifting 3 gears at a time. For specialized owners, be aware that on the 11 speed bikes there may be an extension on your derailleur hanger that you need to remove and then mount this directly onto the frame. That threw me for a while before I realized I could remove that piece.
| Length | 20 centimetres |
| Sport | Cycling |
| Included Components | Rear Derailleur |
| Product dimensions | 17.78 x 17.78 x 12.7 cm; 413 Grams |
| Is discontinued by manufacturer | No |
