Which Groupset?

Lots of good things in terms of travel and being able to disconnect the rear derailleur. And yes definitely less to consider in terms the wiring. Shimano 11sp setup is largely the same for 12sp (other than battery and derailleur) and a 105 12sp derailleur is similarly priced to Rival?
A few things that puts me of AXS for a TT setup is:

• blip box is large and not easy to conceal on most frames
  
• stuck with SRAM chainrings and the flat top chain
  
• no combined shifter/brake
  
• derailleur compared to new Shimano is enormous (if you are looking for an aerodynamic setup)
  

Thanks for the feedback.

Regarding the cassette, it is VERY flat where I am racing, the 36 was for a 'just in case' and to try and be a bit of a cheapskate. Suppose it makes sense to just spend the extra £200 and build something for all terrain.

Have to admit, I'm hesitant about getting into the AXS ecosystem, mainly for the limited chainrings, but it looks like rotor etc do options. The XDR will also reduce flexibility with swapping wheelsets easily. Brakes aren't a concern, but I had no idea the AXS RD was so large.

I was considering Di2, but the cabling concerns me, and I don't want to rely on others to fit/fix. I probably should just learn...Also, there are still shift cables between the frame/cockpit which makes travel slightly harder I guess.

7100/8100 seems a good option, but there doesn't appear to be any option for a wireless cockpit for TT (though a blipbox type thing).

Been doing some reasearch, and it seems the blipbox hiding issue can be solved. I was aware of these wireless blips, but didn't do much reading before: https://www.slowtwitch.com/Products/Components/The_Low-Down_On_SRAM_s_99_Wireless_Blips_8220.html

$99 a pair, but they seemed rather unsuitable as bar end shifters (clearly not what they were intended for). Seemingly, you need a Blip Box to initially pair, but after that, it is not even necessary.

I was trying to think of how they could be better adapted for extensions, but it seems a wonderful person has already done it:
https://www.thingiverse.com/thing:5335609

If I understand this right, this means that once you have paired them, you can leave the blipbox/primary shifters at home/give it back to the person you borrowed it from, and then you have truly wireless shifting from the bar ends?

Wow, I had no idea they could work without a blip box permanently in range, that's pretty cool. I guess you just need to figure out how to get hold of some (and maybe some spares in case they run out of battery at an inopportune moment).

I love that there is a 3D printed solution for them already!

Just one last thing on disconnecting and packing into a box, I presume you aren't disconnecting brakes etc? If it's just the extensions then depending on where the Di2 junction box is, likely you'd only need to unclip one or max two di2 cables, and that's it. In my setup it's just the one...

11spd SRAM eTap TT group and additional blips are another £50 typically. Original price is probably pretty optimistic though...

Thanks! I was contemplating 11 speed eTap for my road bike for a while, but the availability of spares is just too much of a concern.

I actually took the plunge yesterday and bought some new Rival AXS stuff. After some reading of other forums (mostly WW), seems there are lots of people who seem to have got AXS working perfectly well with Shimano 12 speed bits. So I bought the following:

Ultegra 12 speed cassette and chain
Rival FD and RD
The wireless blips
Praxis rings for my existing Red cranks (Praxis say they are AXS and Shimano 12 speed compatible)

Need to source a 'master' controller to pair with the derailleurs, but there's a pretty knackered (but still working) Rival shifter on ebay I'm watching.

It's definitely experimental and for now I'm just going to try it on my old TT, but I'm hopeful from comments online that it will work. Worst case scenario, I'll just buy an AXS cassette/chain and XDR freehub/wheelset (would need to buy a disc wheelset for the new TT frameset I have my eyes on anyway).

We installed AXS with a shimano cassette and chain. It works pretty good. Can't comment in the FD but won't expect much problems if set up right.
If it was me, for a TT bike I'd go AXS 1x.

you need a Blip Box to initially pair

You can use a mtb eagle axs shifter to make the initial pairing with them too

https://www.thingiverse.com/thing:533560­9

Is there anyone on the forum who could print these?
I'd be keen to get a pair too.

seems there are lots of people who seem to have got AXS working perfectly well with Shimano 12 speed bits

really interested to hear how you get on. would like to go AXS but the cost of chain, crankset, cassette really really put me off....!

but the cost of chain, crankset, cassette

its getting close to 11 speed thanks to brexit and other shit

I haven’t mixed and matched on my road bike, but I use a shimano, chain, cassette and chainring with an axs mech on my mtb and it’s flawless. Arguably better than what it was with a full sram set up.

I imagine axs road mechs with 12 speed shimano cassette, chain and chainrings would be fine.

FD shifting might not be ideal though due to the different tooth jumps from big ring to small ring.

Need to source a 'master' controller to pair with the derailleurs, but there's a pretty knackered (but still working) Rival shifter on ebay I'm watching.

what is the role of this btw? what levers are you using?

https://r2-bike.com/SRAM-GX-Eagle-AXS-Controller-12-speed

Gx axs shifter for only 80 euros would do the job as master controller

IIRC the Rival AXS RD jockey wheels (or at least one of the two) have a narrow-wide profile specific for the flat-top chain (or its bigger rollers, to be precise). Some people reported getting around this (i.e. avoiding having to use the flat-top chain) by buying a set of GX AXS jockey wheels and swapping them, then use an Eagle chain. Not sure if the Shimano 12-speed chain is different and works with the stock Rival AXS pulley wheels. I wonder if it was possible to just do some dremeling to modify the (potentially) incompatible Rival pulley wheel.

Aye that’s a good point, one of the jockey wheels has a narrow wide profile. fwiw I tested a Rival AXS mech on a mountain bike with an 11 speed chain and cassette and it shifted fine in the work stand.
The eagle axs jockey wheels mesh fine with a 12 speed shimano mtb chain.
There’s no need to use an eagle chain though, 12 speed shimano road and mtb chains are the same.

Having said all that, I think it’s very likely the Rival mech would work fine without bothering to swap out one of the jockey wheels.

I have two hybrid setups, on one I swapped the jockey wheels, on the other I didn’t bother- both seem to work as well as the other (which is excellently).

Both Shimano cassette, chain and crank with an AXS mech and shifter

in MTB they dont stipulate flat top chain, I am doing the same with sunrace cassette

Regarding the cassette, it is VERY flat where I am racing, the 36 was for a 'just in case' and to try and be a bit of a cheapskate.

When I was racing flat TTs, Mainly in the SE, I ran a 56T chainring with a 11-28 which was fine. I would think a 36 is overkill.

Is it possible to change the shift ratio (or however you word it) on Sram mountain bike trigger shifters for use with a Sram rival rear derailleur? Both 11 speed. Changing works but is a bit clunky sometimes.

Not sure exact model of shifters.

SRAM stuff needs whatever they call the actuation to match, so either exact actuation, 1:1 actuation or X actuation at both ends, if it says the same thing it'll work. If it's different then maybe there's a problem solver that'll work but I'd get new shifters or mech.

Ratio sell a cable fin for derailleurs that mod an MTB one to road pull ratio. So the inverse must be possible surely? You'd have to harvest the cable fin from a broken or decommissioned one though ...

https://ratiotechnology.com/product/cable-fin/

https://bikerumor.com/how-to-hack-a-sram-road-group-with-eagle-derailleur-for-massive-budget-mullet-gearing/

I am trying to find a 9100 dura ace crankset in 180mm length. The only place that I can find with stock is bike24 and they don't ship to UK post-brexit.

I can get you the powermeter ones for a cool £1k or just a regular left arm for £175.

Saw those prices, £1k and doesnt include chainrings.