Electronic & Hydraulic Shifting (Di2, Ui2, customisations)

Rear mech and shifter would be £765.60 from Sigma, plus those pulleys at lets say £160, this would not be a cheap "will it work?" experiment.

Would a 6770 shifter that hadn’t been updated from new (I believe) operate a 6870 RD? Just borrow one and plug it in and see?

Worth a try. If it doesn’t work I think the e-tube software would install the right firmware to get everything working together.

I think firmware upgrades are the problem, I think mix and match 10sp and 11sp was allowed in early versions and then Shimano banned it as they realised the loophole meant you didn’t need a full new group for 11sp upgrades

Not for shifters. Every Di2 shifter ever was compatible with modern setups last time I checked.

(Ignoring 7970)

Here's the compatibility chart.

https://bike.shimano.com/en-EU/e-tube/project/compatibility.html#guide_list

Probably not - it'll probably need a firmware update. With a firmware update you're good to go - Brommers Bike #3 uses 6770 shifters and 6870 mechs.

Not for shifters.

This. Confirmed.

Finally got my Hope RX4+ and got them fitted. Not sure what I was expecting. They stop the bike and it doesn't howl. So thumbsup

I finally got round to fitting my axs shimano mash up.

At first it didn't seem like it would give a result I was happy with. Aligning the mech in the second cog as per sram advice didn't work well at all.
I aligned it with the 6th cog and so far it seems good.
I had wondered about the pulley wheels, haven't got round to trying shimano 12 speed pulleys in the axs mech but don't feel like it needs it.

Shimano chain? I’m tempted to try this as well, surprisingly difficult to find any detailed posts by someone who has done it.

Shimano chain and cassette.
I'd read that chain retention would likely be compromised if I kept the eagle chain ring. Abandoning the four hundred quid xx1 chainset on a whim seemed daft. Finding a reasonably priced chainring that used the Sram direct mount but with the Shimano hg12 tooth profile took a bit of googling. Theres a wolftooth ring that ticks the box. It was released for the EE Wings to run them on a 12 speed Shimano set up. Price is a bit steep though, £100.
Option i went with is this North Shore Billet one at £53. Sram direct mount with hg12 tooth profile.

There really aren't any detailed posts on the best set up. I read this article and it convinced me it was worth trying.

The first result was a bit shit but I've now aligned the centre of the pulley wheel with the centre of the 6th cog and it gives the best set up. No rasping in the smaller cogs but some slight noise in the 50t but I can live with that.

The b-gap adjustment I've just went with trial and error. The Bikemag article says: "When in the second to largest cog, the tip of the tooth on the guide jockey wheel of the SRAM AXS derailleur is 10 millimeters from the tip of the tallest tooth of the largest cog on the Shimano cassette."
But he doesn't mention if he done this with the suspension sagged or not. Sram say it should be set under sag and Shimano don't seem to say one way or another.
I've ended up with the top pulley wheel about 13mm away from the the tallest tooth on the largest cog. This is without the shock under sag.
So far it feels quite good, you can definitely shift up under power without the horrible crunch I was getting with the sram cassette.
I'll wait until I've been out a ride on Sunday before I pass final judgement but I don't see my self going back.

Tempted to get the gx axs mech for my other bike now.

I may be pointing the obvious here but when I do a SRAM derailleur I normally go in the second largest cog and do the b screw in enough the pulley don't overlap with the largest, otherwise you get that crunch as the pulley moves the chain against the big cog going up. Not sag or anything, just hanging on the stand.

^^Do you have the issue referenced in that articles comments about the upper pulley being a narrow/wide design and having issues meshing with the chain?

Best advice I've read on setting up AXS b-screw was "turn it until you get no noise shifting from 2nd to 1st cog while riding it"
Apparently that works out to be about 13-15mm, which is what the plastic b-tension tool is, just a lot less faff than setting it sagged in a stand

Can't comment in SRAM-Shimano 12 speed compatibility. Only thing I've heard is the spacing is not the same, so yeah align in the middle as opposed to second largest cog.

Has Shimano abandoned Di2 on their mtb groupsets?

i really hope so unless they go wireless

GX AXS appeals to me as well! I was toying with putting drops on my MTB with Rival AXS shifters but the ETA on those is 2022 lol.

Would have trolled @BareNecessities nicely.

I was toying with putting drops on my MTB

1 Attachment

Has Shimano abandoned Di2 on their mtb groupsets?

I expect not, but the total lack of any information - even under embargo as the Dura Ace stuff was - suggests that there's nothing coming soon.

I've ordered an AXS shifter and mech to have a play with an AXTR setup myself.

I've ordered an AXS shifter and mech to have a play with an AXTR setup myself.

if you end up hating it, I will buy. I just cant bring myself to replace the inner cable on MTB. (internal and carbon)

I was toying with putting drops on my MTB

You own a mountain bike?

Yes I tried just about every combination of B-gap settings. I used the axs specific purple tool while under sag and the method you've described which is similar to how sram suggest setting it with out the tool.
"Chain Gap Adjustment without Gauge
Shift the chain into the 2nd largest cassette cog. The gap between the tallest teeth of the largest cassette cog and the upper pulley must be 5 mm"

But no matter what, I couldn't get it shifting the way I expected it to. I bought the park derailleur hanger tool to rule out a bent hanger and found that it was straight.

Yeah this pretty much where I ended up with the full sram set up. But it was still a bit clunky under power.

With the shimano hybrid set up its pretty much the same, about 13mm in the stand and about 15 or 16mm under sag.
The difference is it now shifts nicely under power and doesn't have the loud clunkyness of the full sram system.

Theres still part of me thinks that there must be a way to have the sram system working better than I had it.

Do you have the issue referenced in that articles comments about the upper pulley being a narrow/wide design and having issues meshing with the chain?

I haven't encountered this yet. So far I've only tested the bike sprinting up and down the street but didn't notice the jockey wheel having any issue.