[ianlewis23]

Hello,
I’m planning to upgrade my mechanical setup to DI2. I was going to buy the handlebar Junction A (EW-RS910) and the wireless unit ( EW-WU111) as I assumed this would let me neatly send data to my Garmin 520. But I’ve been led to believe that I could use the SC-9051 that is usually used on mountain bikes, which seems to double up as both a junction A and a display unit.

Is this correct? If I buy this can I save having to get another Junction A, a wireless unit, and a compatible display? Any downsides?

Thanks

Topic

[Anonymous]

Actually I think thats

Actually I think thats correct, I remember doing it a few years back when I started using Di2 with an external battery on my old Boardman SLR9.8. The brains were added to the seatpost battery unit much later – I use that now with an EW-WU11, which is a neater solution when used with a Garmin Edge and also adds BT for connection with the iPhone E-Tube app. I agree the Wahoo Elemnt and Bolt (and Roam) are sluggish with Di2 response, always have been – and the Di2 support by Wahoo is way behind Garmin in other ways (available fields, a-button controls, for example).

[kil0ran]

I ran the external bottle

I ran the external bottle cage XTR battery case (which takes the newer seatpost style battery rather than the “brick”) with 6870 – my thinking at the time was that I’d eventually get a frame with internal routing and I didn’t want to buy the battery twice. I remember thinking about getting the display and potentially running a pair of climbing shifters alongside the standard road levers. Mostly in a fit of “because I can” rather than any practical reason 🙂

[hawkinspeter]

kil0ran wrote:

Vaguely remember that the M9050 was a way of getting semi-auto shifting that didn’t arrive on the road groupsets until the R8000 version of Di2

Don’t see how. The ‘brains’ of the Di2 system lives with the battery, so enabling auto/semi-auto shifting required older systems to get a newer internal seat post battery.

[kil0ran]

Vaguely remember that the

Vaguely remember that the M9050 was a way of getting semi-auto shifting that didn’t arrive on the road groupsets until the R8000 version of Di2

[hawkinspeter]

I did try one of those but

I did try one of those but found that when I paired it with a Wahoo Elemnt Bolt, there was often a bit of lag with displaying the gear. The Bluetooth does run down the battery a bit quicker but it’s not a big difference.

[Pilot Pete]

I run an EW-WU111 and can

I run an EW-WU111 and can display rear (and front, but don’t) gear position and Di2 battery level on my Garmin head unit. Doesn’t use any more battery power than any other displayed item and is hidden in the frame so no clutter on the bars either.

PP

[kil0ran]

Yep, that should work. I

Yep, that should work. I mixed XTR Di2 stuff (the external battery case) with Ultegra 6870 on a build and it was fine 

[ianlewis23]

Great. Thanks
Great. Thanks

[hawkinspeter]

I’ve been using the slightly

I’ve been using the slightly older SC-M9050 IIRC and there’s no issue with compatibility with road Di2.

It can replace the handlebar junction box and there’s no need for the separate wireless unit with this – it takes 3 cables, so that’s one going to the in-frame junction box/battery and one each for the two handlebar controls/brifters.

I love it as it gives you a constant illustration of the approximate battery level and also your current gear. I don’t use the wireless aspect of it as I found the phone app wasn’t as easy/reliable as just plugging in a laptop (I’ve got a handheld laptop – 8 inch screen – it’s easy to just pop it on the handlebars while it does a firmware update etc).

Downsides are higher battery consumption and it uses up some handlebar estate – more of an issue with aero bars where you’ve only got a small space to mount stuff.

 

[Author]

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