Shimano GRX, with its gravel specific ergonomics, optimized gearing options, rugged reliability, and quiet and stable drivetrain, sets itself apart from the rest of the component world

RD-RX817: SHIMANO GRX DI2 Rear Derailleur - SHIMANO SHADOW RD+ - 42T Maximum Low Sprocket - 11-Speed

The SHIMANO GRX derailleur, featuring an integrated chain stabilizer mechanism, offers a quieter and more secure shifting experience on mixed terrain. A switchable ON/OFF chain tensioner allows for seamless shifting on both smooth and rough surfaces. The RD-RX817 DI2 version takes advantage of SHIMANO's electronic shifting technology, providing precise and synchronized shifting. It is compatible with mtb cassettes with a maximum low sprocket of 42T.


- Silent and uninterrupted rear shifting on rough terrain
- Adjustable chain stabilizer prevents chain slapping and drops
- SHIMANO SHADOW RD+ technology for smooth and reliable shifting
- Switchable stabilizer ON/OFF for optimal performance on various terrain
- Gravel-tuned clutch tension for optimal performance
- Compatible with current road DUAL CONTROL LEVER
- Top sprocket: Maximum 11T, Minimum 11T
- Low sprocket: Maximum 42T, Minimum 40T


-Model Number: RD-RX817
-Series: GRX DI2
-Color: Series color
-Weight: 318 grams (average)
-Rear Speeds: 11-speed
-Mounting Options: - Direct attachment (conventional) - direct mount
-Total Capacity: 31T
-Low Sprocket: - Maximum 42T - Minimum 40T
-Top Sprocket: - Maximum 11T - Minimum 11T
-Fluoric Coated Link Bushings: 4
-Pulley Bearings: - Sealed bearings for the guide, tension, and teeth pulleys
-B-Axle: - Hollow axle
-Di2 Connectivity: - Wired Di2 shifting and firmware update by E-TUBE PROJECT
-Ports and Connectors:
- SD50 port: 1 piece 

Genuine, brand new, boxed Shimano product - Biketart are an official UK Shimano stockist.

Shimano GRX Di2 RD-RX817 11 Speed Shadow+ Single Rear Mech


Barcode: 4550170443177

Shimano GRX, with its gravel specific ergonomics, optimized gearing options, rugged reliability, and quiet and stable drivetrain, sets itself apart from the rest of the component... Read more

£254.95 RRP £309.99SAVE 17%

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  • Black Black
Size Please select
  • 42T


Delivery Information

We have a range of delivery options on orders. Most importantly, if your order is over £50 then delivery is free!

All Biketart orders are fully trackable. You will get a tracking number by email when your order is shipped which will allow you to track it with Royal Mail or DPD.

In-stock orders placed by 4pm will be processed the same day.

Any items displaying "in-stock with supplier, despatched in 2-3 days" on the product page cannot be despatched the same day as they will be shipped to us from the supplier when you place your order.

Read on to discover the delivery options available to you on your order.

Delivery Services

Standard Tracked: All orders over £50 are eligible for free standard tracked delivery by Royal Mail. For orders under £50 there is a £2.99 charge. Orders sent using standard tracked are usually delivered in 2-3 days.

Priority Tracked: For £3.99 your order is sent by premium tracked delivery which gives a 1-2 day (including Saturdays) delivery timescale. This service is provided by Royal Mail who will usually deliver on Saturdays. Orders must be placed by 4pm.

Next Day Courier: If you require next-working-day delivery then this is provided by DPD and is £6.99. Orders must be placed by 3.30pm and be fully in-stock in order to be processed before our daily DPD collection.

Saturday Delivery: You can select Saturday delivery options from DPD at the checkout.

Bike Delivery: Bikes are always delivered by courier. After placing a bike order your bike is fully assembled and tested before being carefully boxed for shipping. Because of this build process it is not always possible to offer next-day delivery on a bike. Please do get in touch if you want to know a specific despatch day on any bike on our website. Call us on 01227 832582 or email

Returns Info

We offer a 30 day return period on our items. We ask that items are returned in their original packaging and in re-sellable condition. We do not pay returns postage.unless we have made an error with your order.

We cannot accept the return if the item is not correctly packaged and is damaged in transit during the return trip back to us.

    Please do not stick any tape or labels to the products branded outer packaging.

      If you require an exchange it is recommended that you re-order the correct size/item and return the item you do not wish to keep to us for a refund.

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