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Shimano RD-M3020-8 Acera 7/8-Speed Rear Derailleur Black

Shimano

Shimano RD-M3020-8 Acera 7/8-Speed Rear Derailleur Black

Regular price $45.00 Full price
Sale price $45.00
Club price
Regular price $49.99 Full price
SRAM GX Eagle Lunar 12 Speed Derailleur

SRAM

SRAM GX Eagle Lunar 12 Speed Derailleur

Regular price $237.00 Full price
Sale price $237.00
Club price
Regular price $239.00 Full price
32% Off Full Price
Shimano RD-R9250 Dura-Ace Di2 12-Speed Rear Derailleur

Shimano

Shimano RD-R9250 Dura-Ace Di2 12-Speed Rear Derailleur

Regular price $679.00 Full price
Sale price $679.00
Club price
Regular price $999.00 Full price
Shimano Ultegra Di2 RD-R8150 Rear Derailleur 12 Speed

Shimano

Shimano Ultegra Di2 RD-R8150 Rear Derailleur 12 Speed

Regular price $439.99 Full price
Sale price $439.99
Club price
Regular price $499.99 Full price
Shimano High Grade Guide & Tension Pulley Set

Shimano

Shimano High Grade Guide & Tension Pulley Set

Regular price $22.00 Full price
Sale price $22.00
Club price
Regular price $24.99 Full price
Shimano Cues Shadow RD-U6000 Rear Derailleur 10/11-Speed Medium

Shimano

Shimano Cues Shadow RD-U6000 Rear Derailleur 10/11-Speed Medium

Regular price $85.00 Full price
Sale price $85.00
Club price
Regular price $89.99 Full price
29% Off Full Price Clearance
Shimano RD-R8150 Ultegra 12-Speed Derailleur

Shimano

Shimano RD-R8150 Ultegra 12-Speed Derailleur

Regular price $439.99 Full price
Sale price $439.99
Club price
Regular price $625.00 Full price
Shimano 105 R7000 11 Speed Medium Cage Derailleur

Shimano

Shimano 105 R7000 11 Speed Medium Cage Derailleur

Regular price $105.00 Full price
Sale price $105.00
Club price
Regular price $119.99 Full price
Shimano Standard Guide & Tension Pulley Set

Shimano

Shimano Standard Guide & Tension Pulley Set

Regular price $18.00 Full price
Sale price $18.00
Club price
Regular price $19.99 Full price
Shimano Deore Shadow + M5120 10/11 Speed Derailleur

Shimano

Shimano Deore Shadow + M5120 10/11 Speed Derailleur

Regular price $79.00 Full price
Sale price $79.00
Club price
Regular price $89.99 Full price
Shimano R8150 Ultegra Di2 12 Speed Front Derailleur

Shimano

Shimano R8150 Ultegra Di2 12 Speed Front Derailleur

Regular price $299.00 Full price
Sale price $299.00
Club price
Regular price $307.99 Full price
BBB RollerBoys Derailleur Pulleys 11T

BBB

BBB RollerBoys Derailleur Pulleys 11T

Regular price $26.00 Full price
Sale price $26.00
Club price
Regular price $29.99 Full price
Shimano Tourney Rear Derailleu 6/7speed RD-TY300

Shimano

Shimano Tourney Rear Derailleu 6/7speed RD-TY300

Regular price $21.00 Full price
Sale price $21.00
Club price
Regular price $23.99 Full price
Shimano CUES Shadow RD-U8000 Rear Derailleur 11-Speed 50T Max

Shimano

Shimano CUES Shadow RD-U8000 Rear Derailleur 11-Speed 50T Max

Regular price $136.00 Full price
Sale price $136.00
Club price
Regular price $143.99 Full price
Shimano Dura-Ace R9250 Di2 12 Speed Front Derailleur

Shimano

Shimano Dura-Ace R9250 Di2 12 Speed Front Derailleur

Regular price $399.00 Full price
Sale price $399.00
Club price
Regular price $409.99 Full price

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Shimano RD-M3020-8 Acera 7/8-Speed Rear Derailleur Black

Shimano

Shimano RD-M3020-8 Acera 7/8-Speed Rear Derailleur Black

Regular price $45.00 Full price
Sale price $45.00
Club price
Regular price $49.99 Full price
SRAM GX Eagle Lunar 12 Speed Derailleur

SRAM

SRAM GX Eagle Lunar 12 Speed Derailleur

Regular price $237.00 Full price
Sale price $237.00
Club price
Regular price $239.00 Full price
Shimano Cues Shadow RD-U6000 Rear Derailleur 10/11-Speed Medium

Shimano

Shimano Cues Shadow RD-U6000 Rear Derailleur 10/11-Speed Medium

Regular price $85.00 Full price
Sale price $85.00
Club price
Regular price $89.99 Full price
Shimano Tourney Rear Derailleu 6/7speed RD-TY300

Shimano

Shimano Tourney Rear Derailleu 6/7speed RD-TY300

Regular price $21.00 Full price
Sale price $21.00
Club price
Regular price $23.99 Full price
Shimano Deore Shadow + M5120 10/11 Speed Derailleur

Shimano

Shimano Deore Shadow + M5120 10/11 Speed Derailleur

Regular price $79.00 Full price
Sale price $79.00
Club price
Regular price $89.99 Full price
Shimano CUES Shadow RD-U8000 Rear Derailleur 11-Speed 50T Max

Shimano

Shimano CUES Shadow RD-U8000 Rear Derailleur 11-Speed 50T Max

Regular price $136.00 Full price
Sale price $136.00
Club price
Regular price $143.99 Full price
Shimano Cues RD-U4000 Shadow 9-Speed Rear Derailleur 46T

Shimano

Shimano Cues RD-U4000 Shadow 9-Speed Rear Derailleur 46T

Regular price $68.00 Full price
Sale price $68.00
Club price
Regular price $71.99 Full price
Shimano Altus M310 7/8 Speed Derailleur

Shimano

Shimano Altus M310 7/8 Speed Derailleur

Regular price $35.00 Full price
Sale price $35.00
Club price
Regular price $39.99 Full price
Shimano Deore RD-M6200 Shadow RD+ 12-Speed MTB Rear Derailleur

Shimano

Shimano Deore RD-M6200 Shadow RD+ 12-Speed MTB Rear Derailleur

Regular price $85.00 Full price
Sale price $85.00
Club price
Regular price $89.99 Full price
32% Off Full Price
Shimano RD-R9250 Dura-Ace Di2 12-Speed Rear Derailleur

Shimano

Shimano RD-R9250 Dura-Ace Di2 12-Speed Rear Derailleur

Regular price $679.00 Full price
Sale price $679.00
Club price
Regular price $999.00 Full price
29% Off Full Price Clearance
Shimano RD-R8150 Ultegra 12-Speed Derailleur

Shimano

Shimano RD-R8150 Ultegra 12-Speed Derailleur

Regular price $439.99 Full price
Sale price $439.99
Club price
Regular price $625.00 Full price
Sram X01 Eagle AXS 12 Speed Rear Derailleur Max 52T - Lunar (Battery Not Included)

SRAM

Sram X01 Eagle AXS 12 Speed Rear Derailleur Max 52T - Lunar (Battery Not Included)

Regular price $899.00 Full price
Sale price $899.00
Club price
Regular price $925.00 Full price
Shimano Deore Shadow+ RD-M5100 11-Speed Rear Derailleur Long Cage 51T Max

Shimano

Shimano Deore Shadow+ RD-M5100 11-Speed Rear Derailleur Long Cage 51T Max

Regular price $72.00 Full price
Sale price $72.00
Club price
Regular price $74.99 Full price
Shimano Ultegra Di2 RD-R8150 Rear Derailleur 12 Speed

Shimano

Shimano Ultegra Di2 RD-R8150 Rear Derailleur 12 Speed

Regular price $439.99 Full price
Sale price $439.99
Club price
Regular price $499.99 Full price
Shimano Alivio Shadow M3100 9 Speed Rear Derailleur

Shimano

Shimano Alivio Shadow M3100 9 Speed Rear Derailleur

Regular price $60.00 Full price
Sale price $60.00
Club price
Regular price $61.99 Full price
Shimano Altus M370 9 Speed Derailleur

Shimano

Shimano Altus M370 9 Speed Derailleur

Regular price $42.00 Full price
Sale price $42.00
Club price
Regular price $44.99 Full price
Shimano 105 R7000 11 Speed Medium Cage Derailleur

Shimano

Shimano 105 R7000 11 Speed Medium Cage Derailleur

Regular price $105.00 Full price
Sale price $105.00
Club price
Regular price $119.99 Full price
Shimano RD-U2000 Essa 8 Speed Rear Derailleur Shadow Medium Max 45T

Shimano

Shimano RD-U2000 Essa 8 Speed Rear Derailleur Shadow Medium Max 45T

Regular price $65.00 Full price
Sale price $65.00
Club price
Regular price $69.99 Full price
Shimano High Grade Guide & Tension Pulley Set

Shimano

Shimano High Grade Guide & Tension Pulley Set

Regular price $22.00 Full price
Sale price $22.00
Club price
Regular price $24.99 Full price
Shimano Deore XT M8100 12 Speed Rear Derailleur

Shimano

Shimano Deore XT M8100 12 Speed Rear Derailleur

Regular price $199.00 Full price
Sale price $199.00
Club price
Regular price $209.00 Full price
Shimano Deore Shadow+ RD-M6100 12-Speed Rear Derailleur Long Cage 51T Max

Shimano

Shimano Deore Shadow+ RD-M6100 12-Speed Rear Derailleur Long Cage 51T Max

Regular price $89.00 Full price
Sale price $89.00
Club price
Regular price $100.99 Full price
Shimano Tourney TX800 7/8 Speed Derailleur Silver

Shimano

Shimano Tourney TX800 7/8 Speed Derailleur Silver

Regular price $27.00 Full price
Sale price $27.00
Club price
Regular price $29.99 Full price
AForge 009 Derailleur Hanger

Wheels Manufacturing

AForge 009 Derailleur Hanger

Regular price $40.00 Full price
Sale price $40.00
Club price
Regular price $45.99 Full price
25% Off Full Price Clearance
Shimano 105 Shadow RD-R7100 Road Rear Derailleur 12-Speed Short

Shimano

Shimano 105 Shadow RD-R7100 Road Rear Derailleur 12-Speed Short

Regular price $89.00 Full price
Sale price $89.00
Club price
Regular price $120.00 Full price
Shimano R8150 Ultegra Di2 12 Speed Front Derailleur

Shimano

Shimano R8150 Ultegra Di2 12 Speed Front Derailleur

Regular price $299.00 Full price
Sale price $299.00
Club price
Regular price $307.99 Full price
Shimano Dura-Ace R9250 Di2 12 Speed Front Derailleur

Shimano

Shimano Dura-Ace R9250 Di2 12 Speed Front Derailleur

Regular price $399.00 Full price
Sale price $399.00
Club price
Regular price $409.99 Full price
Shimano RD-M9100 XTR Shadow+ Rear Derailleur 12-Speed

Shimano

Shimano RD-M9100 XTR Shadow+ Rear Derailleur 12-Speed

Regular price $369.00 Full price
Sale price $369.00
Club price
Regular price $399.99 Full price
Shimano XTR RD-M9100 Shadow+ 12-Speed Long Cage Rear Derailleur

Shimano

Shimano XTR RD-M9100 Shadow+ 12-Speed Long Cage Rear Derailleur

Regular price $369.00 Full price
Sale price $369.00
Club price
Regular price $399.99 Full price
Shimano Ultegra R8000 11 Speed Medium Cage Derailleur

Shimano

Shimano Ultegra R8000 11 Speed Medium Cage Derailleur

Regular price $149.00 Full price
Sale price $149.00
Club price
Regular price $159.99 Full price
SRAM RD NX Eagle Rear Derailleur

SRAM

SRAM RD NX Eagle Rear Derailleur

Regular price $175.00 Full price
Sale price $175.00
Club price
Regular price $198.00 Full price
Shimano Standard Guide & Tension Pulley Set

Shimano

Shimano Standard Guide & Tension Pulley Set

Regular price $18.00 Full price
Sale price $18.00
Club price
Regular price $19.99 Full price
Shimano Sora R3000 9 Speed Double Derailleur

Shimano

Shimano Sora R3000 9 Speed Double Derailleur

Regular price $49.00 Full price
Sale price $49.00
Club price
Regular price $54.99 Full price
Shimano Deore XT RD-M8200-SGS 12 Speed MTB Rear Derailleur

Shimano

Shimano Deore XT RD-M8200-SGS 12 Speed MTB Rear Derailleur

Regular price $199.00 Full price
Sale price $199.00
Club price
Regular price $209.99 Full price
MicroShift Advent M6195M Rear Derailleur 9 Speed

MicroShift

MicroShift Advent M6195M Rear Derailleur 9 Speed

Regular price $100.00 Full price
Sale price $100.00
Club price
Regular price $104.99 Full price
19% Off Full Price Clearance
Shimano Tourney TY500 6/7 Speed Rear Derailleur

Shimano

Shimano Tourney TY500 6/7 Speed Rear Derailleur

Regular price $24.00 Full price
Sale price $24.00
Club price
Regular price $29.99 Full price
Shimano Ultegra R8000 11 Speed Short Cage Derailleur

Shimano

Shimano Ultegra R8000 11 Speed Short Cage Derailleur

Regular price $139.00 Full price
Sale price $139.00
Club price
Regular price $149.99 Full price

Find Your Size

Step 1: Measure your height

  • Take off your shoes
  • Stand with your back straight against a wall
  • Balance a book on your head to mark your height on the wall
  • Measure your height by the distance from the floor to the mark
cm

Find Your Size

Step 2: Adjust your inseam

  • Based on your height, we’ve calculated a starting point.
  • You can measure your inseam by tucking a book between your legs so there is pressure but it isn’t uncomfortable.
  • Inseam typically falls with 5cm of the average.
cm

Find Your Size

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For the we suggest the following size.

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Recommended sizes will now be highlighted on the page.

Things to Consider When Shopping for Derailleurs

When shopping for derailleurs, it helps to know what type of riding you do and what drivetrain you're working with. Derailleurs are the mechanical components responsible for moving your chain across gears, and choosing the right one depends on a few key factors. First, consider whether you need a front or rear derailleur, as both serve different functions within your drivetrain. Next, think about compatibility with your existing groupset and the number of speeds your bike runs, since derailleurs are designed to work within specific systems. Riders shopping for MTB derailleurs will have different requirements to those on road bikes, so knowing your discipline helps narrow things down quickly. If you're simply maintaining your current setup, jockey wheels are a straightforward way to restore smooth shifting without replacing the full derailleur. Explore the different types of derailleurs below to find the right fit for your riding needs.

Commonly Asked Questions about Derailleurs

Expert Advice

Handlebars Buying Guide
Buying Guides

Handlebars Buying Guide

Handlebar design and dimensions are integral to how your bike handles and ultimately, how well it fits you. Bikes will generally come with handlebars of the appropriate size and shape, however, an upgrade can give you that extra performance edge. Road Bike Handlebars The most important consideration when buying road bike handlebars is width with the goal being to try and match the width of the bars to your shoulders to ensure a comfortable riding position. Secondly, you'll need to decide on what shape you require. The curve in road bike handlebars is referred to as 'drop' with a larger drop allowing for a more aggressive and aerodynamic riding position, however if you're not confident you'll be able to stay down in your drops for long periods of time then a more compact design might be the best for you. Finally, you should consider what material you'll require. Road bike bars are available in both carbon and aluminium and the choice largely depends on how much weight you want to save vs. how deep your pockets are. Shop Road Handlebars Mountain Bike Handlebars As is the case with road bikes, mountain bike handlebars come in a variety of widths to suit different rider sizes and styles. Wider bars provide greater control in corners, but can be a handful around obstacles in a tight and twisty trail. If you're into downhill riding then you'll want extra strong bars to put up with the rough ground and heavily landings you'll be encountering on the trails, whereas if cross-country riding is more your style then you will be more concerned with weight rather than strength. It is also important to ensure that you get the correct diameter bar to fit your stem with the most common size being 31.8mm. The final consideration to make is rise, which refers to how much higher the ends of the bars sit in relation to the centre clamp. A lower rise gives a more aggressive riding position however won't be as comfortable over longer rides as bars with a larger rise. Shop MTB Handlebars

Oct 8, 2025
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Bike Stems Buying Guide
Buying Guides

Bike Stems Buying Guide

The right size bike stem will greatly improve your riding efficiency and comfort. They are available in varying lengths to accommodate riders of different heights. Short stems provide a more upright riding position. While a longer stem will produce a more 'stretched out' position. Stems are also available in a variety of angles which allows you to effectively raise or lower your handlebars to achieve the optimal riding position. See All Bike Stems

Oct 8, 2025
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Easy Bike Maintenance Velo Academy
Cycling Advice

Easy Bike Maintenance Velo Academy

No matter how often you ride, it's well worth learning a few things about how to maintain and adjust your bike. 99 Bikes and Velo Academy have put together a series of videos to help you learn a few basic procedures to help you ride more comfortably, and possibly also get your out of a sticky situation (like failing brakes!) Adjust Seat and Handlebars In this video you'll learn how to adjust your bike seat and handlebars to make riding as comfortable as possible. For this, you'll need a torque wrench. Adjust Brakes In this one, you'll find out what to do if you notice your brakes aren't sitting quite right. You'll need an allen key or multi-tool. Clean and Lubricate a Chain In this video, you'll learn how to clean and re-lubricate your chain. You'll be needing citrus degreaser, chain cleaner, chain lubricant, water and a clean rag. Fix a Flat Tyre Finally, this video will show you how to change a flat tyre. For this, you'll need tyre levers, a new inner tubeC and a pump. See All Tools and Maintenance

Jul 3, 2025
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