Electronic & Hydraulic Shifting (Di2, Ui2, customisations)

Are there benefits to the RX even when running a 11-23 cassette/time trial set-up? I know little about di2 kit but thought the RX kit was the mountain bike cross-over for wide range cassettes...

I think the RD is same price, you get a clutch for running 1x so why not?

Any work around for 11 speed with these?

No work around required. They'll work fine with an 11 speed set up.

Ah cool, I thought they'd updated that out

Ah thought they were way more pricey - will have a dig cheers

You can't mix 10 and 11 speed mechs any more. Shifters aren't an issue.

you get a clutch for running 1x

You also get a dérailleur geometry which is a worse match for a race cassette. The chain is always going to be pretty well controlled on a short cage RD with only enough slack chain to accommodate a 23T big sprocket, getting a clutch doesn't seem like a priority when it comes at the cost of slower shifts.

I always wondered about that but never knew how to phrase it. Most common thing that comes to mind is the Ceramic Speed cages. They promise all sorts of smoother and specifically, faster shifting, but is there any truth to it or simply snake oil?

simply snake oil?

The claims about lower friction losses are true, but poor value for money.

Claims of faster shifts might be true for some cassette arrangements but not others, the geometry of a RD is always optimised for only one cassette, so changing it will change which cassette it is optimised for. If you're not as clever as Shimano it might also make the performance fall-off either side of the optimal cassette steeper than it was with the stock cage.

make the performance fall-off either side of the optimal cassette

Practically speaking, after installing a fair few so far, it always seemed to be the case. Shifting performance decreased on the upper or lower limits of the cassette irrespective of the amount of adjustment that was done.

Is this down to the actual parallelogram of the derailleur or the pre-load on the spring?

Amusingly enough, it was mostly triathletes that wanted them installed in conjunction with Oval rings. Correlation?

Is this down to the actual parallelogram of the derailleur or the pre-load on the spring?

With SRAM, it's all about the parallelogram and cage geometry, because the B-pivot is fixed. With Shimano, the P spring fights the B spring, so the balance between the two has a slight effect on the position of the upper pulley relative to the sprocket.

in conjunction with Oval rings. Correlation?

Yes, just correlation. Oval rings have a negligible effect on the RD

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Do I need junction box a if I have a display unit?

Can I run the shifter into the display then down to junction b, which connects to xt rear and battery?

what is better about the brakes other than clearance? my tcr is limited by fork crown more than the caliper anyway.

Think so.

Better give it a go...

Yep works a treat...

So junction box a for di2 available £40 posted pic tomo...

Yes you can, no junction a needed if you have a display.
That's how I setup this thing and it works a treat:-
https://www.lfgss.com/conversations/301477/newest/

Hello all. I have now read every page of this thread!

Very informative and amusing at times ;). Just thought I'd share one of my di2 builds. This Kinesis was a POC to see if I could build a 1x di2. I've since upgraded it (new crankset) and I have an XT di2 mech and larger cassette to put on her at some stage.

I look forward to sharing with you all and helping where I can. I've built and ridden all the caliper brake di2 groupsets (or at least in parts) and I must say that I agree that the jump from 6870/9070 to 8070/9170 is just not that big especially from the electronics perspective. Eliminating cross-chaining (latest firmware) is all good and well but it means removing the rear wheel for travel is more annoying.

I'm looking to build an aero disc di2 bike in the next year or so to replace a bike so selling and I will be building some nice wheels to go on it.

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Very tidy!

Nice clean chain :)

Is that a good spot for junction box? Doesn’t it get covered in spray?

I thought it might get hammered but not really. It's pretty well protected by the downtube.

Either way, when you ride in the mud there aren't many parts of the bike that are safe! Mud is pretty indescriminate!

Makes it a bit tricky to adjust gearing on-the-fly though. I want to get the bar-end charge port but until then will stick with under the stem.

You're absolutely right, although I've very seldom had to adjust di2 once past initial setup.

The bar end junction is nice but honestly it's a patch. Shimano should have gone wireless by now.

Etap is so much easier to fit and I prefer the yaw front derailleur. I admit the shifting vs da di2 isn't as quick but it's marginal imho.