Over 2,000,000 Million Customers Served!!!

Need Help? Click the Live Chat to Talk to a Gearhead 💪

Enjoy Free Shipping on Orders Over $75 – Available Within the Lower 48 States!

SKU: RD6401

Shimano ZEE RD-M640-SS Rear Derailleur 10-Speed Short Cage with Clutch, Wide-Range Compatibility up to 36T Cog, Shadow RD+ Technology, Mountain Bike Rear Derailleur for Off-Road & DH Performance

Regular price $90.15
$90.00 Sale price $90.15 Regular price
Sale Sold out
Unit price
/per 
  • Free Shipping Over $75
  • 30 Day Returns
  • Satisfaction Guaranteed!

$10 Gift Card

at 250 points

$25 Gift Card

at 500 points

$75 Gift Card

at 1,000 points

This is a pre order item. We will ship it when it comes in stock.

$10 Gift Card

at 250 points

$25 Gift Card

at 500 points

$75 Gift Card

at 1,000 points

Description
Specifications

Upgrade your mountain biking setup with the Shimano ZEE RD-M640-SS Rear Derailleur - engineered for aggressive riding and versatile performance. Designed specifically for 10-speed mountain bike drivetrains, this short cage derailleur delivers precise shifting, durability, and advanced technology to enhance your riding experience.

Materials & Construction:

Constructed with high-quality, lightweight materials, the Shimano ZEE RD-M640-SS features a rugged gray finish that withstands harsh trail conditions. Its robust construction ensures longevity and reliable performance in demanding environments.

Performance & Engineering:

Built to optimize wide-range cassette compatibility, this derailleur supports cassettes with up to 36T cogs, providing excellent gear coverage for steep climbs and fast descents. Shimano's advanced Shadow RD+ clutch technology minimizes chain slap and noise, maintaining chain tension and reducing derailleur bounce on rough terrain, ensuring a smooth and silent ride.

Components & Technology:

Equipped with Shimano's proven Shadow RD+ clutch system, this derailleur offers enhanced chain retention and stability. The short cage design allows for quick, accurate shifts while maintaining a lightweight profile, perfect for aggressive trail riding, enduro, and downhill MTB applications.

Style & Use Case:

Designed with a sleek gray aesthetic, the ZEE RD-M640-SS seamlessly integrates into any mountain bike build focused on durability and high performance. Ideal for trail riders, enduro enthusiasts, and downhill racers seeking reliable shifting, clutch technology, and wide gear range compatibility.

Innovative Features:

- Wide-Range Compatibility: Supports cassettes up to 36 teeth, perfect for tackling varied terrain and steep inclines.

- Clutch Technology: Shimano's Shadow RD+ clutch reduces chain slap, noise, and derailleur bounce for a more controlled ride.

- Durability & Reliability: Heavy-duty construction withstands mud, water, and impacts common in aggressive mountain biking.

Specifications:

- Max Cog Size: 36T

- Drive Type Compatibility: Shimano Mountain 10-speed

- Mount Type: Shimano Rear Direct Mount / 10x1 Standard

- Weight: 250 grams

- Chain Wrap Capacity: 25 teeth

- Cage Length: Short

Enhance your mountain bike's performance with the Shimano ZEE RD-M640-SS Rear Derailleur - the perfect combination of engineering innovation, durability, and versatile gearing for serious trail riders. Shop now to experience confident, precise shifting on every ride!

  • Enhanced durability with a lightweight aluminum construction built to withstand rugged mountain biking conditions.
  • Features Shimano's innovative Shadow RD+ clutch technology, significantly reducing chain slap, noise, and chain drop for smoother, quieter rides.
  • Designed for wide-range cassettes up to 36 teeth, offering versatile gear options ideal for aggressive trail riding and enduro adventures.
  • Compatible with 10-speed Shimano mountain bike shifters and direct mount systems, ensuring seamless shifting performance and easy installation.
  • Engineered with advanced component technology, the ZEE RD-M640-SS rear derailleur provides exceptional reliability and precise gear indexing for demanding, technical terrains.
Largest Cog36
ColorGray
Rear Der/Shifter CompatibilityShimano Mountain
Rear Derailleur Mount Type10x1 Standard
Rear Derailleur Mount TypeShimano Rear Direct Mount
Drivetrain Speeds10
Weight250
Chain Wrap Capacity (teeth)25
Cage LengthShort
Shipping
Returns
About Us
Contact Us

We pride ourselves on our ability to ship and deliver your gear with excessive speed! We ship from 22 locations throughout the United States and most orders will arrive in 3 days or less with Free Shipping on orders over $75!

The nitty gritty, for specific delivery timelines please pay attention to the delivery timelines on the product pages and the time frame estimated in the carts. If you need a part by a specific day, please contact us by chat, phone, or

Chat

Talk with a representative

Start Chat

Email

info@365cycles.com

Send Email

Phone

603-968-5797

Call Now

Most orders placed during the workweek before 1:00 PM Eastern time ship the same day, but during peak/holiday season or depending on inventory location handling time can take up to 48 hours. If you have questions regarding shipping estimates, don't hesitate to get in touch with us before placing the order. There is a direct signature requirement for all orders over $500.

We provide the you the ability to utilize multiple shipping & billing addresses, based upon what fits your current needs. However you are responsible to maintain and update any new address changes, as 365 Cycles will not be held liable for orders being shipped to an incorrect address.

  • Our Mistake: If we messed it up you can rest assured we are going to make it right. Contact us by email, phone, or chat and we will make your head spin with how quick we fix it
  • Warranty: We are an authorized retailer for everything we sell, so rest assured your product is covered under the manufacturer's warranty. Contact Us if you are having an issue and we will make sure you are taken care of
  • Just don't want it anymore: We have a 30-day return policy for orders within the US. We offer refunds on returned items that are brand new and in their undamaged, original packaging. Customers are responsible for the cost of return shipping. Damaged, installed, and used items as well as those without original packaging are not eligible for returns. If it's returned in this condition it may be denied and sent back to you

If you need to return your order please email us at info@365cycles.com, call us at 603-968-5797, or use the live chat on our site.

Chat

Talk with a representative

Start Chat

Email

info@365cycles.com

Send Email

Phone

603-968-5797

Call Now

*Please allow up to 3 business days for us to process your return*

365 Cycles puts the customer above everything. Our number one goal is your satisfaction. When you press the shift lever you want the gears to shift, and when you buy bicycle parts, you want the bicycle parts to arrive on time in new condition. With over 60,000 products and 22 warehouse locations throughout the country, we have the parts you need and they are coming in hot!

Living an active lifestyle is just that, a lifestyle that never goes away and our goal is to always exceed your expectations so we can take this lifelong journey together. We strive to have the parts you need, at competitive prices with unmatched shipping speeds!

If there is ever an issue with an order we will work at warp speed to fix our mistake and make sure you never go a day without a bicycle! If you are not receiving the quality of service you need from one of our exceptionally qualified bicycle experts, tell them Ben Berman told you to tell them "Customer Loyalty" and then name your terms.

Our team is waiting to help you 7 days a week and they are more qualified to help than I am but if you ever feel like you're not getting the service you need I’m personally asking you to email me at ben@365cycles.com with "CUSTOMER LOYALTY" in the title and I will personally handle your order.

Over the years we have served millions of satisfied customers and continue to serve many of them today. With your feedback, we are confident we can take this lifelong journey together and build a friendship that goes beyond parts and accessories.

“If you want to go fast, go alone, if you want to go far, go together.” -Someone Smart

Ben Berman Founder & CEO of 365 Cycles


Company Core Values: 

These were established by the members of our team and we use them every week to call out team members who have shined in one of these areas. Feel free to let us know at info@365cycles.com if someone you worked with has gone above and beyond in one of these areas. 

Customer Loyalty

Put yourself in their shoes and support those who support us.

You Control the Outcome

If it is to be, it’s up to me" You are personally responsible for controlling the outcome.

Seek Understanding

Understanding the answer is more important than the answer.

Progress Not Perfection

Pick a direction, analyze the results, and be willing to change course.

Will to Win

Customers, 365 Team, Partners, all need the will to win. Bring the Will to Win to every conversion.

Keep Moving

Move the body, move the mind, and remove any hurdles to achieving an active lifestyle.

Do the Right Thing:

Doing the right thing is more important than doing the thing right.

Stronger together:

If you want to go fast, go alone, if you want to go far, go together. Get your team involved and become stronger together.

Chat

Talk with a representative

Start Chat

Email

info@365cycles.com

Send Email

Phone

603-968-5797

Call Now

Customer Reviews

Based on 51 reviews
80%
(41)
12%
(6)
8%
(4)
0%
(0)
0%
(0)
H
Harry Ng

great authentic Shimano product. have it working with a 11x42 cassette without any modifications (1x10) with Zee shifter;

M
Michael Stapleton

I paired this with a Zee 10spd shifter and a 1x10 drivetrain and took it over some very bumpy trails. No dropped chain and it shifts precisely. Worth the purchase;

T
Thomasajimenez1980

My old retro bike with ZeeDH and Box 4 8 speed shifter. This thing rips. I normally ride single speed but I decided to try some road bike gearing on a old 1990's balance frame. 26th front 12-19 gears out back. This thing climbs great out of the saddle. So if you want to run the Zee derailer on 8 spd the box 4 shifter is your jam!;

`
`Ben Ansley

I’ve been running an original Sram X7 long cage for a couple years on a 1x10 conversion. My local shop recommended the Zee but it was backordered so I was lucky to find it on Amazon. Best decision I’ve ever made. No more dropped chains and shifts extremely quick and crisp. I was able to change it out and get it adjusted pretty easily after watching a few YouTube videos. Out of box it feels sturdy and well made. I highly recommend;

A
Amazon Customer

I was new to mountain biking and this was going on my Cannondale catalyst 4 hardtail. For the money this is one of the best derailleurs you can get and I can say that with confidence. shifts extremely smooth on flat and on slight inclines for more harsh inclines it will still shift it just doesn't like it too much. However behind that and the relatively small range cassette. I have no complaints. if you are looking for something for the trails where there will be a lot of climbing you might want to steer away from this but if you are up for building some serious muscle it is good. Like I said in the title I have run this since 2020 and have had zero problems with it. The durability is also extreme it can take a real bashing and it has taken several rock hits and come out okay.;