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The new SW-RS801-T tops shifter was introduced when Shimano released Ultegra R8100 / R9200 to the world. It lets you shift your 12-speed bike from the tops, muc

12-speed-HDB-STI-satellite-dealer-manual.pdf

ST-R9270 / ST-R8170 / SW-RS801 Dealer Manual

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While previous satellite shifters were one unit, these newer ones consist of a shifting unit and a clamp, or band. In theory, you could actually stick the unit onto your handlebar using some strong double-sided tape, 

Alternatively, slide the unit onto the band and then use the provided double-sided tape to attach it to the handlebar. You then use a tie-wrap to more permanently secure it to the handlebar.

These are sold as a pair, weigh **5.7g** *each* and come with a **260mm wire**.

Satellite shifters will **not** work with 105 Di2 shift levers, since those do not have any extension ports.

![component-12s-satellite-shifter-lengths.png](https://assets.bettershifting.com/component_12s_satellite_shifter_lengths_f92c3222e6.png)


The **12-speed** satellite shifters are pretty neat - they work by plugging them into the bottom port of the **Ultegra** and **Dura-Ace** shift levers (not 105), and they work right out of the box! 

Sure, you can program them to perform other functions, but you generally don't have to.

Shimano makes **three** different versions of the SW-RS801 satellite shifter:

- [SW-RS801-S Sprint shifter](/component/dura-ace-12-speed-satellite-drops-sprint-shifter-sw-rs801-s/). This satellite shifter is placed in the drops and comes with a **100mm wire** and a **24mm** diameter **clamp**.
- [SW-RS801-T Tops/Climbing shifter](/component/dura-ace-12-speed-satellite-tops-shifter-sw-rs801-t/). Placed on the tops, usually near the stem. Comes with a **260mm wire** and a **31.8mm clamp**.
- [SW-RS801-E TT/Tri aero bar shifter](/component/dura-ace-12-speed-aero-bar-satellite-shifter-sw-rs801-e/). These *new* -E satellite shifters come with a **740mm wire** and a **24mm clamp**. They're meant to be installed to clip-on aero bars.

All of these shifters are essentially the same unit, the only differences are in the wire length and clamp size.

<LImage alt="SW-RS801-S and -T unboxed" src="https://assets.bettershifting.com/SW_RS_801_ST_unboxed_v2_4d10a3a9a4.jpg" width="1150" height="581" caption="Two SW-RS801-T shifters, with the 31.8mm clamp and the 24mm clamp" />

These shifters **only** work when plugged into the bottom port of Ultegra and Dura-Ace shifters, and you cannot even plug them into a different port if you try. The connectors have *alignment tabs* that make sure you don't use them in a regular E-Tube port.

## Why extend satellite shifters?
Most people who want to extend 12-speed satellite shifters want to use their sprint shifters on their clip-on aero bars. These shifters aren't cheap, and I get it. If you can use the same shifter in two different locations, why not? Also, the **-E** version of the SW-RS801 satellite shifter isn't available for purchase until late 2023.

Others want to use shifters in places other than the ones intended by Shimano. 

Whichever the reason, you *can* definitely extend the satellite shifters. You can also use this method to **connect two satellite shifters to the same shift lever**. For example, a sprint shifter and a climbing shifter.

### One method - splicing the wires
A while ago I thought the only method to extend satellite shifters was to splice the wires. This involves cutting the connector off of the satellite shifter wire, and stripping the outer housing and the two tiny inner wires.

<LImage src="https://assets.bettershifting.com/010_tiny_wires_4c63e5d3b6.jpg" alt="Tiny wires" width="1150" height="452" />

While it can definitely be done, it's not recommended for novices. Cutting up Di2 wires, and soldering or crimping wires together can cause some strange Di2 issues. 

No one wants to ride a bike that automatically shifts every time you hit a bump in the road. 

### Preferred method: use an inline junction
I love hacking Di2, but this doesn't always have to involve cutting up wires.

To extend the satellite shifters, I'll use the [EW-JC302 inline junction](/component/inline-2-port-junction-ew-jc302/).

## Extend a satellite shifter, step by step
Before we get started, make sure you have these items:

- The SW-RS801 satellite shifter you want to extend
- An [EW-SD300 wire](/component/di2-electric-wire-ew-sd300/) of the right length
- [EW-JC302 inline junction](/component/inline-2-port-junction-ew-jc302/)
- A sharp knife

<LImage alt="EW-SD300, SW-RS801, EW-JC302, knife" src="https://assets.bettershifting.com/001_boxes_and_knife_07567ca6d0.jpg" width="1150" height="671" />

### Step 1: Unboxing
Take your shifter, junction, and wire out of their boxes. As you can see below, the alignment tabs prevent you from plugging the satellite shifter into the [EW-JC302 junction](/component/inline-2-port-junction-ew-jc302/).

<LImage alt="Cannot just connect the RS801 to the JC302" src="https://assets.bettershifting.com/003_jc200_does_not_fit_6ce73d5551.jpg" height="497" width="1150" caption="This won't fit, the alignment tabs are in the way" />

### Step 2: Cut the alignment tabs off
Use the knife to **carefully** cut off the alignment tabs.

<LImage alt="Cut the alignment tabs off" src="https://assets.bettershifting.com/004_cut_satellite_shifter_ab90de2597.jpg" width="1150" height="690" />

Yes, really - cut them off! This will not impact the shifter's functionality at all, and this will make it fit into a regular SD300-type port.

<LImage alt="Cut the satellite shifter tabs" src="https://assets.bettershifting.com/005_cut_satellite_shifter_66403c441f.jpg" height="494" width="1150" caption="While it looks nice in the photo, don't cut your tabs off like this" />

Again, **be careful**. Cutting off the alignment tabs won't harm the satellite shifter's functionality, but cutting off half of the connector definitely will.

Be sure to cut off **only** the alignment tabs.

Do not cut off more than required.

Either cut straight down or lay the plug on a flat surface and cut it that way.

<LImage alt="Cut off too much..." src="https://assets.bettershifting.com/007_cut_off_too_much_d317948b88.jpg" width="1150" height="481" />

Here's what happens when you cut too much off. This shifter still works just fine, but it isn't pretty. Take care.

### Step 3: Plug it in!
That's it! You're done.

Plug the satellite shifter into the [JC302 inline junction](/component/inline-2-port-junction-ew-jc302/), and connect that [EW-SD300 wire](/component/di2-electric-wire-ew-sd300/) to both the inline junction and your shift lever.

<LImage alt="SW-RS801 extended using EW-JC302" src="https://assets.bettershifting.com/006_all_connected_2b02abcee9.jpg" width="1150" height="713" />

**Use the bottom port**.

With the alignment tabs cut off, and with the satellite shifter extended using a junction and regular [EW-SD300 wire](/component/di2-electric-wire-ew-sd300/), the satellite shifter now fits into *any* port on your shift lever.

However, **ONLY** the **bottom port** will work. 

<LImage src="https://assets.bettershifting.com/diy_satellite_shifter_shifter_1875d19ce7.jpg" caption="Only use the bottom port. Please." alt="Only use the bottom port" width="1150" height="624" />

Really. Don't even try to use one of the other ports.

The satellite shifters do not have any firmware or circuitry that'll let them function in any regular port. You **must** use the **bottom port** on the shift levers, and **only** the bottom port.

Your bike won't explode or catch fire when you plug these shifters into a regular port by mistake, by the way. The satellite shifters just won't work. 

Don't do it :).

## Multiple shifters?
I used [EW-JC302]() on this page, but you could also use [EW-JC304](). This junction has **four** ports, and it'll let you connect up to **three satellite shifters** to a single shift lever.

All you need to do is cut the alignment tabs off.

<LImage alt="Two DYI shifters" src="https://assets.bettershifting.com/008_two_satellite_shifters_25bc239421.jpg" width="1150" height="678" caption="Two DYI satellite shifters" />

This is great when you want to use both sprint shifters and climbing shifters. Or when you want to [build your own satellite shifters](/build-your-own-cheap-di2-satellite-shifters/).

One little **caveat** though - all satellite shifters connected to a single port on a shift lever will perform the same function. You can **not** program them individually - the bottom port on a Di2 shift lever is just a *dumb* port.

## Share your setups!
Have you extended your shifters? Or installed four or more satellite shifters on the same bike? Why? How?

I love reading about your hacks, and seeing them, of course! 
Leave a comment below, or [send me a message or WhatsApp](/contact/).

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Extending 12-speed Di2 satellite shifters is relatively easy. I'll use an EW-JC302 junction, an EW-SD300 wire, and a knife to extend a couple of satellite shifters.

Extend 12-speed SW-RS801 Satellite Shifters

Half a year ago Shimano submitted their [R9250 rear derailleur](/component/dura-ace-shadow-rear-derailleur-rd-r9250/) to the FCC for approval. This FCC filing is required because of the wireless (BluetoothLE/ANT) technology in the new semi-wireless 12 speed Di2 groupsets. Back then there wasn't a whole lot we could tell from the documents, other than this:

- It's called R9250
- It uses the [BT-DN300 battery](/component/internal-battery-bt-dn300/)
- It therefore also uses the [EW-SD300 wires](/component/di2-electric-wire-ew-sd300/)
- It's semi-wireless, both derailleurs are connected to the battery

Part of the FCC documents is also the **manual** for the rear derailleur itself. 

Unfortunately Shimano requested that to be private/confidential, so we couldn't see it. 

Until today. FCC documents can only be confidential for so long, and today the 6 month period ended.

## What can we learn from the manual?
Let's walk through the manual and see what we can find. You can actually download the manual on any FCC related website, but I've also uploaded it to bettershifting.com for your convenience: [R9250 Rear Derailleur / Battery charger manual](https://assets.bettershifting.com/r9250_manual_20036cc49d.pdf).

If you want to skip ahead to the most interesting sections of this page, here are some links:

- [No more junction boxes](#nomorejunctions)
- [Synchronized Shifting and Wireless functionality](#synchrowireless)
- [The rear derailleur charging port](#chargeport)
- [Battery status.. for the main battery and shift levers](#batterystatus)

![r9250_manual_overview.png](https://assets.bettershifting.com/r9250_manual_overview_f1c23803c1.png)

Interesting! It looks like the **charging port** has moved from the Junction A to the rear derailleur. Not only that, but the rear derailleur now also features an **LED** and a button **mode switch**.

![r9250_charging_port_led_details.png](https://assets.bettershifting.com/r9250_charging_port_led_details_bbd0c653ae.png)

## No more junctions boxes! No wires up front {#nomorejunctions}
Since the new system will be semi-wireless - the derailleurs are connected to the battery via [EW-SD300](/component/di2-electric-wire-ew-sd300/) and that's all - it makes sense for the rear derailleur to have all these things. The entire Junction A will no longer be needed, reducing clutter and wiring at the front of the bike.

Also, a patent previously filed by Shimano suggests that the battery will have an integrated B Junction. The battery in the image below has three ports, two of which would be [EW-SD300 ports](/component/di2-electric-wire-ew-sd300/). The third port is most likely *not* an [EW-SD300 type](/component/di2-electric-wire-ew-sd300/) and used for sensors, lights, etc.

![Two ports on the new Di2 battery](https://assets.bettershifting.com/battery_two_ports_632ae343e6.png)

What will you do with extra components like satellite shifters or climbing shifters? It looks like you'll be able to plug those in at the Shift levers - they'll have 1-2 [EW-SD300 ports](/component/di2-electric-wire-ew-sd300/) and one satellite shifter port. More on that at the bottom of this page.

### Synchroshift and Wireless function {#synchrowireless}
So what does the button do? Quite a lot actually. Look at this image:

![r9250_manual_operation_modes.png](https://assets.bettershifting.com/r9250_manual_operation_modes_0eac818d79.png)

That right, it:

- Lets you check the battery level
- Changes shift mode
- Enables BluetoothLE connection mode
- Switches to (micro)adjust mode
- Is used to pair switches

Missing from the list above is **RD Crash Reset mode**. This is either a mistake.. or the functionality has moved to the E-Tube Mobile app. The latter makes sense, as the button now suddenly has a lot of functionality tied to it.

And yeah, Synchronized Shift still exists:

![r9250_manual_shift_modes.png](https://assets.bettershifting.com/r9250_manual_shift_modes_6d01d4ee04.png)

### Battery status {#batterystatus}
The battery status LED works just like before, indicating the charge level of the [BT-DN300 battery](/component/internal-battery-bt-dn300/):

![r9250_manual_battery_info.png](https://assets.bettershifting.com/r9250_manual_battery_info_150543c386.png)

However, looking at the **About wireless functions** section of the manual, this particular bit is interesting:

![r9250_manual_wireless_functions.png](https://assets.bettershifting.com/r9250_manual_wireless_functions_38f2c32916.png)

> Dual control lever battery level information

Previously, users on WeightWeenies have suggested that the shift levers would be self-charging and not require any batteries to operate. If so, there would be no need for battery level data to be sent over ANT or BluetoothLE. I haven't actually seen the new levers myself, so I'm just guessing here. Your guess is as good as mine :).

### Charging the battery via the rear derailleur {#chargeport}
So yeah, you'll charge your 12 speed Di2 battery via the rear derailleur. The charging cable looks a lot like Shimano's power meter charging cable. It's not 100% the same though, there are subtle differences. 

![r9250_manual_charger_plug_in.png](https://assets.bettershifting.com/r9250_manual_charger_plug_in_ccaa6e87ed.png)

Either way, this new charger will certainly be a lot less fiddly than the current SM-BCR2 charger and the other end just plugs into a USB port. No more charging brick!

![r9250_manual_charging_cable.png](https://assets.bettershifting.com/r9250_manual_charging_cable_2bb359db47.png)

This is what the prototype unit looks like from the outside:

![RD-R9250 outside](https://assets.bettershifting.com/RDR_9250_unit_3a025be51d.jpg)

You can see the charging port at the bottom and the [EW-SD300 Electric Wire](/component/di2-electric-wire-ew-sd300/) port on the top. 

The inside of the unit looks like this:

![RD-R9250 inside](https://assets.bettershifting.com/RDR_9250_inside_8da5565aec.jpg)

The red arrows are Shimano's, but I added the letters myself. This is what they indicate:

- **A**: Antenna
- **B**: BluetoothLE / ANT module
- **C**: Charging port
- **W**: Wireless integrated Circuitry

Note that the circuit board has **[RD-R9250](/component/dura-ace-shadow-rear-derailleur-rd-r9250/)** printed on it.

Also, take a good look at the part of the circuit board the [EW-SD300 wire](/component/di2-electric-wire-ew-sd300/) plugs into. Because the same part can be found on the circuit board for the ST-R9270 Hydraulic Disc Dual Control Lever:

![ST-R9270 inside PCB](https://assets.bettershifting.com/STR_9270_inside_7af77848be.jpg)

Not one, but three of them! Now.. as with previous generation hydraulic dual control levers, you probably will *not* be able to connect three wires to it - current generation levers feature *two* E-Tube ports [(EW-SD50 type](/component/di2-electric-wire-ew-sd50/)). However, two ports just like the current levers seems reasonable. 

User **ooo** [from WeightWeenies](https://weightweenies.starbike.com/forum/viewtopic.php?f=3&t=156208&p=1690848#p1690846) suggests that it's 1 [EW-SD300 port](/component/di2-electric-wire-ew-sd300/) + 1 satellite port for the hydraulic levers and 2 [EW-SD300 ports](/component/di2-electric-wire-ew-sd300/) + 1 satellite port for the rim brake levers.

The size of the unit pictured above is **16.6 mm** x **23.5 mm**, by the way:

![ST-R9270 PCB drawing](https://assets.bettershifting.com/STR_9270_transmitter_schematics_eadea8c81a.png)

## Release...
When will it actually be released or even announced? No one outside of Shimano really knows. I'll be there to keep you up to date when it happens though! 

September seems likely, but I'm just making an educated guess here.

















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The FCC just released the manual for the new Shimano RD-R9250 12 speed semi-wireless rear derailleur. This page looks at the manual to see if there's any secrets hidden in there.

DURA-ACE R9250 semi-wireless Rear Derailleur Manual published

Shimano's first ever 12-speed Di2 groupset, DURA-ACE R9200 was announced September 1st, 2021. It features wireless shifting, improved disc brakes, and of course, 12-speed cassettes.

Satellite Tops Shifter (12 speed)

DURA-ACE SW-RS801-T

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Specifications

Related components

Related pages

Extend 12-speed SW-RS801 Satellite Shifters

DURA-ACE R9250 semi-wireless Rear Derailleur Manual published

Manuals & other documents