Author Topic: Di2 Failure mode  (Read 38074 times)

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: Di2 Failure mode
« Reply #200 on: 22 May, 2018, 02:18:03 pm »
Brucey has some sort of amazing high-definition television  that the rest of us do not have. For the rest of us it is near impossible in this world  of concealed gear cables routed through the stem to spot whether a tour rider whizzing by is using di2 or not but Brucey, using his special tv adapted by himself, can zoom into the minutest detail of passing bikes and not only that but remotely diagnose the cause of all breakdowns, which are of course attributable to di2.

I had a puncture last week, caused by di2, even though the bike I was riding at the time didn't have di2.

I doubt Brucey adapts TVs by himself.   If he was as good at electronic maintenance as he is at the mechanical variety, he might not be so worried about the advent of electronic gears.

Phil W

Re: Di2 Failure mode
« Reply #201 on: 22 May, 2018, 03:41:16 pm »
I had a puncture last week, caused by di2, even though the bike I was riding at the time didn't have di2.

Di2 is short for Destroy Inner (tubes) 2

simonp

Re: Di2 Failure mode
« Reply #202 on: 22 May, 2018, 03:54:11 pm »
Someone OTP had their LEL ended and frame ruined by Di2* putting their rear mech into the spokes.

* It wasn't Di2.

quixoticgeek

  • Mostly Harmless
Re: Di2 Failure mode
« Reply #203 on: 22 May, 2018, 05:44:55 pm »

Page 9 of this thread. I'm impressed. I've really enjoyed the discussion. Keep the comments coming.

Currently I'm leaning very much towards going for Ultegra Di2, with Mechanical disks. Sub compact chainset (46/30 from FSA), with IQ² power meters, On an S&S coupled Steel frame. With a nice SON dyno hub with Edelux II lighting...

Now I just need to finalise the design of the frame, and find the money for it all...

Keep the discussion going, I'm enjoying it.

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Re: Di2 Failure mode
« Reply #204 on: 22 May, 2018, 05:58:58 pm »
Just remember that Di2 is a luxury, and you have to factor in the cost of possible replacement constituent parts.

It is a joy to use, particularly on long rides on varied terrain, and it makes even more sense with 11 speed.

Don't put too much store in the words of those who have no actual experience of it, but who's self-regard means they feel their opinion carries more weight than those that do.

Ditto hydro discs.

Re: Di2 Failure mode
« Reply #205 on: 22 May, 2018, 06:11:03 pm »


the failures you think are unacceptable fall firmly into the 'easily preventable, lack of basic maintenance' category. 

They may fall into the lack of basic maintenance category but the fall into the lack of maintenance that isn't obvious it needs doing until it's too late category.
Same with seat posts in steel frames. Welds in - oh, you should have regularly greased it.
BITD you were not allowed a race start in even the most lowly road race unless your bike was checked to make sure it was safe. When non-aero brake levers were the norm, cable failures were quite common inside the brake levers. 
What is needed on many machines is something called 'proactive maintenance'.  Apologies if this is b-obvious but if you blithely carry on riding your bike until even the stupidest most unobservant person would notice a problem, you have gone way past the point at which you should have maintained it.  How do you know your brakes, chain and tyres etc are not worn out? You look at them, of course. Same goes for everything else. Nothing on a decent bike lasts for ever, if it did it would be built too heavy.

 'Obviousness' is all relative; to my mind it is perfectly obvious that stuff wears out, breaks, and goes rusty, and if you want not to be caught out you need to check stuff instead of blithely assuming that it'll be alright today because it was OK yesterday.... ::-)

Quote
BTW the gear cable that goes into the hub gubbins (wrapped twice or more around a small brass pulley) on a rohloff is less than 1.0mm in diameter. It can and does fray and break. When it is frayed even a little bit it is possible for the indexing in the hub not to work which can leave you between gears.

Seasoned riders take a spare cable of this sort on tour with them.  IIRC it is rather fiddly to fit a new one and Rohloff now sell an 'easy fit' version which has the cable installed already on a spare pulley. The 'easy fit' cable kit costs about four times as much as the basic cable kit.

cheers

If the cable failed you would just take the mech off and the gear can be changed with a small spanner.
I've never heard of a frayed cable causing the indexing to fail so would be curious to know where you've got that information from. I could not really envisage how that could possibly happen - the gear change nut doesn't care what the cable is doing, but if it did happen you would just take the mech off and manually put it in whatever gear you choose to be appopriate for single speed.

 I've seen it happen several times and folk who ride their Rohloff much know to take the cable along  as spare part.  On all hubs made before  a certain date (and quite a few afterwards) there is no external mech, the gubbins is built into the end of the hub; the wheel needs to come out and there is some disassembly required to get at the pulley or to manually set the gear. In any case the indexing works via some spring loaded detents; if the cable becomes draggy there is no reason for the shift mechanism to stop moving in one of the usual places, which leaves you between gears sometimes. A common cause of binding is that the frayed strands jam against the sides of the concertina tubes. I have even seen strands poking through the sides of the tubes.

In an emergency (no cable of the correct type available) I have taken a standard gear cable inner, and removed two or three strands from it. With luck this makes it slim enough to fit in the grooves of the rohloff pulley.

Arguably it is bad design, in that it should have been possible to engineer something that didn't use a special (from memory 0.95 to 1.05mm dia) cable. Standard gear inners are ~1.2mm, just too big to go in the grooves.  IIRC a genuine (old) SA 3s gear cable inner is thin enough for this job, but that is about the only standard cable that is.

Quote
It is quite fiddly to replace. I feel I have got the knack at doing it when I've done it, but it needs doing so rarely that by the time the next time comes I've forgot again... I think I've done it once in 7 years :)

yup it is fiddly alright. FWIW the cable is guaranteed to fail by fatigue; in common with a lot of cycle parts the way it is designed is very far from that which would give it an infinite fatigue life. As it happens the stresses in the cable are not wildly different from that seen in some models of shimano STI (e.g. the cable dia to pulley dia ratio) and one of my chums (who changes gear a lot) proved that it was unlikely that any inner he could buy would last more than ~150000 shifts in such an STI. These days he changes the gear inner at a mileage which corresponds with ~130000 shifts and this means he never has to deal with a knackered cable; replacing an unbroken cable is so much easier!

cheers

Ben T

Re: Di2 Failure mode
« Reply #206 on: 22 May, 2018, 06:29:27 pm »
BITD you were not allowed a race start in even the most lowly road race unless your bike was checked to make sure it was safe. When non-aero brake levers were the norm, cable failures were quite common inside the brake levers. 
What is needed on many machines is something called 'proactive maintenance'.  Apologies if this is b-obvious but if you blithely carry on riding your bike until even the stupidest most unobservant person would notice a problem, you have gone way past the point at which you should have maintained it.  How do you know your brakes, chain and tyres etc are not worn out? You look at them, of course. Same goes for everything else. Nothing on a decent bike lasts for ever, if it did it would be built too heavy.
Exactly - you look at them, because they're visible. It's fine for things you can see. But you can't see fraying of the inner because it's hidden inside the outer, just like
the seatpost is hidden inside the frame.


 'Obviousness' is all relative; to my mind it is perfectly obvious that stuff wears out, breaks, and goes rusty, and if you want not to be caught out you need to check stuff instead of blithely assuming that it'll be alright today because it was OK yesterday.... ::-)

I've seen it happen several times and folk who ride their Rohloff much know to take the cable along  as spare part.  On all hubs made before  a certain date (and quite a few afterwards) there is no external mech, the gubbins is built into the end of the hub; the wheel needs to come out and there is some disassembly required to get at the pulley or to manually set the gear. In any case the indexing works via some spring loaded detents; if the cable becomes draggy there is no reason for the shift mechanism to stop moving in one of the usual places, which leaves you between gears sometimes. A common cause of binding is that the frayed strands jam against the sides of the concertina tubes. I have even seen strands poking through the sides of the tubes.

In an emergency (no cable of the correct type available) I have taken a standard gear cable inner, and removed two or three strands from it. With luck this makes it slim enough to fit in the grooves of the rohloff pulley.

Arguably it is bad design, in that it should have been possible to engineer something that didn't use a special (from memory 0.95 to 1.05mm dia) cable. Standard gear inners are ~1.2mm, just too big to go in the grooves.  IIRC a genuine (old) SA 3s gear cable inner is thin enough for this job, but that is about the only standard cable that is.
I have done - don't know exactly, but between 20k and 50k miles - and only changed the cable once or twice - and never had any problems, so I am going to venture forward the theory that it only frays or breaks if it has been installed badly/incorrectly*. There are specific instructions such as ensure the routing is smooth and doesn't have kinks, do not lube it, etc.
Obviously it's possible to very slightly fray the end when inserting it into the barrel...and have most of it contained but one or two strands poking free - I know, I've done it - and it's tempting to think oh it'll be ok. But the solution is not to continue with it, even though it would probably work - but replace the cable, which is rustrating, as you might have to wait a couple of days for it to arrive. Maybe this is where the people you've spoke to went wrong?

* a theory which I think also applies to Di2 as when I had a Di2 bike I never had any problems with it in 5 years.

Quote
yup it is fiddly alright. FWIW the cable is guaranteed to fail by fatigue; in common with a lot of cycle parts the way it is designed is very far from that which would give it an infinite fatigue life. As it happens the stresses in the cable are not wildly different from that seen in some models of shimano STI (e.g. the cable dia to pulley dia ratio) and one of my chums (who changes gear a lot) proved that it was unlikely that any inner he could buy would last more than ~150000 shifts in such an STI. These days he changes the gear inner at a mileage which corresponds with ~130000 shifts and this means he never has to deal with a knackered cable; replacing an unbroken cable is so much easier!

cheers

Yes it would fail due to fatigue... I can't find it now but I vaguely remember reading somewhere that it should be replaced every 20k miles. I wonder how many miles 130,000 shifts is on average?

I guess this is one  'regular' (ish) maintenance thing I can't really get away from. But, to me, a schedule that's well into 5 figures of miles is the right side of the line of how often I want to have to do something. Something that's affected by ingress is the wrong side of the line. Personally.

Ben T

Re: Di2 Failure mode
« Reply #207 on: 22 May, 2018, 06:35:31 pm »
Arguably it is bad design, in that it should have been possible to engineer something that didn't use a special (from memory 0.95 to 1.05mm dia) cable. Standard gear inners are ~1.2mm, just too big to go in the grooves.  IIRC a genuine (old) SA 3s gear cable inner is thin enough for this job, but that is about the only standard cable that is.
er... I don't know whether you are referring to old ones, but mine uses cables that are thicker than standard gear inners. They are the same thickness as brake cables. i.e. thicker!

Re: Di2 Failure mode
« Reply #208 on: 22 May, 2018, 10:54:39 pm »
]
I have done - don't know exactly, but between 20k and 50k miles - and only changed the cable once or twice - and never had any problems, so I am going to venture forward the theory that it only frays or breaks if it has been installed badly/incorrectly*.
Quote
yup it is fiddly alright. FWIW the cable is guaranteed to fail by fatigue; in common with a lot of cycle parts the way it is designed is very far from that which would give it an infinite fatigue life. As it happens the stresses in the cable are not wildly different from that seen in some models of shimano STI (e.g. the cable dia to pulley dia ratio) and one of my chums (who changes gear a lot) proved that it was unlikely that any inner he could buy would last more than ~150000 shifts in such an STI. These days he changes the gear inner at a mileage which corresponds with ~130000 shifts and this means he never has to deal with a knackered cable; replacing an unbroken cable is so much easier!

cheers

Yes it would fail due to fatigue... I can't find it now but I vaguely remember reading somewhere that it should be replaced every 20k miles. I wonder how many miles 130,000 shifts is on average?

the number of shifts varies from rider to rider and also with terrain and gearing system, load on the cables and so forth.  If the gear cables on a rohloff get draggy, that increases the load in the pulley cable and shortens their life.  For example, for my chum 130000 shifts is only about 4000 miles but for me (on the same route with a  different bike with wider spaced gears) it might be nearer 40000 miles, and the loading on the cables is less on some of the bikes I might use. I'd guess for an average rider/terrain it might be around 10-15 thousand miles.

But fatigue is the inevitable death for these cables; a look at the design rules for wire ropes so as to give them a virtually infinite fatigue life will tell you that. BTW one of the elements in getting a long-lived wire rope is to make sure the cable is lubricated internally; the wire strands rub against one another otherwise. For this reason I recommend that you lubricate rohloff cables, even if rohloff don't.

cheers

Re: Di2 Failure mode
« Reply #209 on: 22 May, 2018, 11:29:30 pm »
BTW it was asked upthread why a Di2 system might be more likely to go into the wheel than a mechanical one, especially given that both have mechanical stop screws.

Well in a mechanical system when you go into bottom gear it isn't unusual for the mech position to be mainly determined by the stop screws rather than the indexing; the elasticity in the cable pulls the mech against the stop screw. Not sure if the same protocol applies to Di2 or not.

What anyone who has worked on many bikes may have noticed is that (as well as bent/badly adjusted mechs  going into the wheel instantly) in some cases the rider habitually really hammers the mech into the stop screws and this causes premature wear; the stop screw just digs itself a hole in the part it bears against.

I'd suppose that the same thing might happen with a Di2 system. There is a current sensor that backs the power off if the stall current is reached but until that kicks in the load in the mech is at least as much (actually a lot more) than even the most ham-fisted rider might generate in a mechanical system.

In most of the gears the Di2 system works like any other servo; the system powers until a resolving element of some kind tells the system it is in the right place and the motor quits.  Thus a failure of the resolver (or the programming or the adjustment) might allow the system to power into the end stop for bottom gear and appear to work 'normally' but is actually wearing the stop screw at high speed.

Most systems of this type have a feedback arrangement, i.e. they provide a bigger signal to the motor when there is a greater error in position than is normal; thus if the shift is delayed for whatever reason, the motor will exert more torque than normal and may even overshoot the intended position before settling in on it. This could easily damage the stop screw.

With a mechanical system a rider might notice a noise from the mech tickling the wheel during the overshift (i.e. while they are still pushing on the lever) e.g. because the stop screw is wearing, and realise that the system is getting out of adjustment. They certainly won't be likely to keep hammering on the shift lever after the shift has gone in.  I'm not sure that the same thing will happen with a Di2 system; if the stop  screw limits mech position then it will just wind into the wheel ever more with every shift. If the stop screw is worn or out of adjustment the resolver may position the mech correctly most of the time but if a tiny fault develops in the resolver (or the system doesn't shift soon enough, under load, and then overshoots when the shift happens) then the mech might easily end up in the wheel even if the system worked OK on the workstand.

Remember I said that complex systems have multiple failure modes? Well you might suffer the same kind of fault many times over before being sure what actually caused it; investigating the mangled remains of the mech might not tell you that much.... ::-)

I guess there are two main things so far as users are concerned;

1) you either do (K) or do not (I) understand how the technology works  and
2) you either do (B) or do not (U) believe that the technology is implemented in such a way as it is less likely to go wrong/be unfixable vs alternative systems.

I guess if anything I'm a 'KU'; there are a lot of folk who are IB and some who are KB.

cheers

Kim

  • Timelord
    • Fediverse
Re: Di2 Failure mode
« Reply #210 on: 23 May, 2018, 12:09:24 am »
I'd suppose that the same thing might happen with a Di2 system. There is a current sensor that backs the power off if the stall current is reached but until that kicks in the load in the mech is at least as much (actually a lot more) than even the most ham-fisted rider might generate in a mechanical system.

I can't be the only one thinking of the Commodore 1541 disk drive.

simonp

Re: Di2 Failure mode
« Reply #211 on: 23 May, 2018, 12:26:54 am »
I'd suppose that the same thing might happen with a Di2 system. There is a current sensor that backs the power off if the stall current is reached but until that kicks in the load in the mech is at least as much (actually a lot more) than even the most ham-fisted rider might generate in a mechanical system.

I can't be the only one thinking of the Commodore 1541 disk drive.

oh I think you can

quixoticgeek

  • Mostly Harmless
Re: Di2 Failure mode
« Reply #212 on: 23 May, 2018, 01:13:24 am »

Thinking more about the proposal to ban roadside assistance. Surely a progression of this is that a rider should use the same bike for all stages? Currently most pros will have 3 different bikes at a grand tour, a climber, an aero bike, and a tt bike. If you're not allowing road side assistance, doesn't all the same reasoning say one bike, one tour?

Would certainly mix things up, and could help the poorer teams. A bit like the idea of "one bike cross" in amateur cyclo cross...

if you did go that route, would you allow swapping cassette for the mountain stages? Would you allow adding clip on aero bars on the tt stage?

Maybe we should go back to the original plan where riders rode between the parcours of the stages... and did everything self reliant and oh wait that's the tcr... as you were...

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: Di2 Failure mode
« Reply #213 on: 23 May, 2018, 08:14:06 am »

Thinking more about the proposal to ban roadside assistance. Surely a progression of this is that a rider should use the same bike for all stages? Currently most pros will have 3 different bikes at a grand tour, a climber, an aero bike, and a tt bike. If you're not allowing road side assistance, doesn't all the same reasoning say one bike, one tour?

Would certainly mix things up, and could help the poorer teams. A bit like the idea of "one bike cross" in amateur cyclo cross...

if you did go that route, would you allow swapping cassette for the mountain stages? Would you allow adding clip on aero bars on the tt stage?

Maybe we should go back to the original plan where riders rode between the parcours of the stages... and did everything self reliant and oh wait that's the tcr... as you were...

J

One bike rules are already a thing, either in being far flung races or lower form the hierarchy, for precisely the reasons of stopping riders having to own/transport multiple bikes.

Re: Di2 Failure mode
« Reply #214 on: 23 May, 2018, 09:18:13 am »

Page 9 of this thread. I'm impressed. I've really enjoyed the discussion. Keep the comments coming.

Currently I'm leaning very much towards going for Ultegra Di2, with Mechanical disks. Sub compact chainset (46/30 from FSA), with IQ² power meters, On an S&S coupled Steel frame. With a nice SON dyno hub with Edelux II lighting...

Now I just need to finalise the design of the frame, and find the money for it all...

Keep the discussion going, I'm enjoying it.

J
I assume the mechanical disks are because you want to be able to take it apart with the S&S couplers? If not, seriously consider hydro. They probably fall (even further than mechanical disks!) foul of Brucey's ideals, but they work very well indeed, and need less faffing about with than mechanical disks...

Cudzoziemiec

  • Ride adventurously and stop for a brew.
Re: Di2 Failure mode
« Reply #215 on: 23 May, 2018, 09:41:48 am »

Thinking more about the proposal to ban roadside assistance. Surely a progression of this is that a rider should use the same bike for all stages? Currently most pros will have 3 different bikes at a grand tour, a climber, an aero bike, and a tt bike. If you're not allowing road side assistance, doesn't all the same reasoning say one bike, one tour?

Would certainly mix things up, and could help the poorer teams. A bit like the idea of "one bike cross" in amateur cyclo cross...

if you did go that route, would you allow swapping cassette for the mountain stages? Would you allow adding clip on aero bars on the tt stage?

Maybe we should go back to the original plan where riders rode between the parcours of the stages... and did everything self reliant and oh wait that's the tcr... as you were...

J
Calling it a proposal is probably giving it too much importance. It was just Fotheringham's answer when asked what he thought could be done to make road racing more exciting. His logic was nothing to do with one bike for the whole race, it was that introducing the element of luck would create more drama. Get a puncture on a breakaway or your Di2 sends the mech into the spokes  ;) just before the final sprint and the rider would be frustrated but the crowds would feel the tension, seems to be the idea.
Riding a concrete path through the nebulous and chaotic future.

quixoticgeek

  • Mostly Harmless
Re: Di2 Failure mode
« Reply #216 on: 23 May, 2018, 12:04:26 pm »
I assume the mechanical disks are because you want to be able to take it apart with the S&S couplers? If not, seriously consider hydro. They probably fall (even further than mechanical disks!) foul of Brucey's ideals, but they work very well indeed, and need less faffing about with than mechanical disks...

Not really, it's more that on a the side of a mountain in Scandinavia, I can bodge working brakes with a spare cable, where as with Hydrolics, whilst they look to have a very high MTBF, I am concerned that the failure would be somewhat terminal.

I've been using cable disc brakes for 10 years, I understand them, and know their quirks. I know that Hydrolics are better in every measurable way, but if I lose the liquid due to collission, accident etc... I'm screwed. I can carry a spare brake cable.

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Re: Di2 Failure mode
« Reply #217 on: 23 May, 2018, 05:14:23 pm »
I assume the mechanical disks are because you want to be able to take it apart with the S&S couplers? If not, seriously consider hydro. They probably fall (even further than mechanical disks!) foul of Brucey's ideals, but they work very well indeed, and need less faffing about with than mechanical disks...

Not really, it's more that on a the side of a mountain in Scandinavia, I can bodge working brakes with a spare cable, where as with Hydrolics, whilst they look to have a very high MTBF, I am concerned that the failure would be somewhat terminal.

I've been using cable disc brakes for 10 years, I understand them, and know their quirks. I know that Hydrolics are better in every measurable way, but if I lose the liquid due to collission, accident etc... I'm screwed. I can carry a spare brake cable.

J
Surely the same argument (with the possible exception of the better in every way bit ;) ) applied to Di2?

LittleWheelsandBig

  • Whimsy Rider
Re: Di2 Failure mode
« Reply #218 on: 23 May, 2018, 05:38:46 pm »
Hydraulic brakes with S&S couplers are a painful combination. You have to remove the rear caliper and hose from the frame to allow easy packing of drop handlebars and the two frame pieces. You can split a bare length of brake cable, leaving the rear caliper on the bike.

I've had a S&S Frezoni since 1999. Depending on the exact arrangement (large frames are harder to pack), you sometimes have to unbolt the front rim brake caliper from S&S bikes to get enough cable slack to pack the drop bar. Hydraulic brakes with a hose inside a fork blade or frame would be a no go.
Wheel meet again, don't know where, don't know when...

quixoticgeek

  • Mostly Harmless
Re: Di2 Failure mode
« Reply #219 on: 23 May, 2018, 05:55:49 pm »
Surely the same argument (with the possible exception of the better in every way bit ;) ) applied to Di2?

I can carry a spare Di2 cable, I can fix that at the side of the road. I can always get it into a single gear, maybe even run it as a 2 speed bike (front only).

Di2 and S&S couplers also has the advantage that I don't have to worry about gears going out of alignment everytime I reassemble the bike...

Should I be starting a new thread for Hydraulic brake failure modes?

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Cudzoziemiec

  • Ride adventurously and stop for a brew.
Re: Di2 Failure mode
« Reply #220 on: 23 May, 2018, 06:10:40 pm »
Wouldn't the ideal shifting system for a bike with S&S couplings be Sram Etap, because it's wireless?
Riding a concrete path through the nebulous and chaotic future.

quixoticgeek

  • Mostly Harmless
Re: Di2 Failure mode
« Reply #221 on: 23 May, 2018, 06:12:42 pm »
Wouldn't the ideal shifting system for a bike with S&S couplings be Sram Etap, because it's wireless?

Yes, and no. It means 3 batteries to charge. And as someone who has done wireless stuff both terrestrial and in orbit, wireless stuff is basically black magic and harder to debug. I'll take an electrical cable I can plug/unplug over wireless any day.

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Cudzoziemiec

  • Ride adventurously and stop for a brew.
Re: Di2 Failure mode
« Reply #222 on: 23 May, 2018, 06:26:14 pm »
I've done a lot of stuff in orbit too. Orbit of the sun.  ;D
Riding a concrete path through the nebulous and chaotic future.

Re: Di2 Failure mode
« Reply #223 on: 23 May, 2018, 09:03:49 pm »
there are such things as 'dry break' hydraulic connectors. They are fiercely expensive but they may provide a solution to Hydro brakes and S&S couplings.

BTW hydro brakes will of course (sooner or later) fail to a leak. There is no maintenance regime (other than routine replacement of seal parts, and even then it isn't guaranteed) that helps to stave off this outcome.

 They also have the side effect of making the very lazy (who like to buy these things because they are 'low maintenance', ha!) end up riding dangerous bikes.  With 'open' type hydro brakes the pads can wear down to the backing and there is no clue that this has happened until it is too late.

With other brakes you need to manually adjust them which means you are more likely to keep an eye on the condition of the brake blocks/pads.

cheers

thing1

  • aka Joth
    • TandemThings
Re: Di2 Failure mode
« Reply #224 on: 23 May, 2018, 10:48:09 pm »
Di2 and S&S couplers also has the advantage that I don't have to worry about gears going out of alignment everytime I reassemble the bike...

Absolutely. Not just with S&S coupler reassembly, which is a breeze, but we've had the rear triangle of our tandem rebuilt twice in recent years and both times the RD was just bolted right back on and continued to shift flawlessly without any tuning needed. (FD is a completely different kettle of fish - but that's not the fault of di2 but the stupid clamp on FD mount that you can never get in the same place twice, not to mention chainrings that slowly change shape over time.)

Couplers is not enough to make me go wireless - the time it takes to reconnect the di2 plugs is a minuscule portion of the flying with bike experience.
In fact, a NON-coupled bike is where I'd consider wireless, as internal wiring is contra-indicated.  On a coupled bike internal wiring replacement / maintenance is far more accessible.