Di2 Failure mode

[quixoticgeek]

His view has admirable logical integrity and it might make for more exciting racing, especially if it resulted in the abolition of race radios. Incidentally, I was at a talk recently where William Fotheringham was asked for his suggestions to make racing more exciting and one of them was the abolition of roadside assistance (though not on "human muscular effort" grounds). But it is an opinion on competition and doesn't apply to any other form of cycling.

Except for cyclo-cross where they have the pits with a spare bike that gets power washed between laps...

Or ultra racing, where you can avail yourself of any bike shop you pass that's open...

Interestingly, gcn have a video asking what rules the pros of the Giro would like abolished. And one said the feed one, saying it's an incredibly dangerous place to be. I found it interesting.

J

[Cudzoziemiec]

I presume you're referring to Fotheringham's idea of getting rid of roadside assistance? He was talking in the context of one-day and stage racing, at a screening of A Sunday in Hell (and promo of his book). Ultra-racing is somewhat outside all that, don't know what he'd say about cyclocross.

[Brucey]

re the abolition of roadside assistance; nice idea (and it would focus more  attention on practical, reliable bike designs perhaps).  But it would be subject to the law of unintended consequences.  For example it would lead to more instances of a team member being selected because they are the same build as the team leader (thus are able to supply their bike as a spare) which would favour the richest teams. 

It would also lend weight to the antics of any would-be saboteurs. There have been numerous incidents of folk not involved in the race strewing tacks etc on the road, throwing stuff at riders and who know what else.   There are also documented incidents in which one rider or team's bikes have been the subject of sabotage by other teams. Without roadside assistance those acts would be more likely to be more effective.

cheers

[Hot Flatus]

Bla bla bla

I've just done 340 miles on a bike with di2 and discs.

It was great.

[simonp]

I accelerated hard through the gears today to keep up with a car that dawdled and then accelerated briskly to catch up with the cars ahead as the lights went green. The synchro shift handled it beautifully I didn’t have to back off at all.

[DuncanM]

On topic - it seems that the Di2 "crash mode" caused major problems for George Bennet yesterday at the foot of the Zoncolan. NB he didn't crash, but it cost him a lot of time as riding the Zoncolan in the 11 tooth sprocket is just not possible.

No more trouble than a broken cable would have done, just needed a bike change...

Bike changes weren't allowed on the Zoncolan.

Then why were there motobikes with passengers carrying extra bikes on the back, following the riders up said hill? As well as the Neutral service moto ?

J

True, he just needed a bike change. But when you are in the lead group and you have to stop to wait for your team car/moto with a bike on it at the bottom of a climb, you'll lose at least a minute, and you aren't going to make up a minute on the Zoncolan. I don't know what the frequency of cable failures was in the pro ranks before they went to Di2 (or how frequent "crash mode" is), but this is an extra failure mode (the Di2 cable can still break).

[De Sisti]

I meant to type: "Team cars weren't allowed on the Zoncolan for bike changes".

[Brucey]

cable breakages on pro race bikes are almost unheard of; they are changed on a regular basis anyway and inspected for any problems (along with the rest of the bike) on a daily basis. Doing this is no more difficult than other daily checks such as inspecting the surface of the tyre for cuts etc

 Since they almost invariably  fray before they actually break or cause any shifting/braking problems, the chances of a remotely competent mechanic letting a bike go with a cable that will break the following day is virtually nil.

By contrast if your Di2 system is just about to develop an intermittent fault the following day, you have no chance of doing any inspection  that will tell you this, any more than (say) you would know if you are going to run over something that will give you a puncture.

As I mentioned upthread, I got bored of noting the number of pro racers that couldn't continue because their crappy electrically operated gears had stopped working properly; it literally happens every single day in most stage races, (and has done since they started using systems of this type) but you only tend to see it on TV if it live coverage and it affects one of the main protagonists.

I don't recall as many riders having to stop in the past because their mechanically operated gears had gone wonky; there may be other things that have changed (such as the move to 11s) which may have caused problems to be more frequent but my finger of suspicion is pointed firmly at the Di2 systems as being the most likely culprit.

cheers

[DuncanM]

I think that's another case where the pro rider has different requirements/opportunities to me.
I consider myself a semi competent home mechanic, but I've never checked my gear cables for fraying. Likewise, I have (had) bikes with decent rim brakes, but find the hydro discs need less attention and work better (than cantis, V brakes and dual pivots). Also a super low front end actually causes me pain, so I need a longer head tube that someone who has the strength and flexibility of a pro.
I'm heartened that the industry is making bikes that fit humans rather than race machines, and require less maintenance and checking. Sadly I can't afford Di2 - if it ever makes it down to 105 I will probably get it.

[mzjo]

Bla bla bla

I've just done 340 miles on a bike with di2 and discs.

It was great.

I am sure that that should read
 " I've just done 340 miles on a bike and it was great.
The bike with Di2 and discs worked like a charm and was a real pleasure to ride  "

Otherwise I might read that you had ridden 340 miles sensually stroking your gearchange buttons and pumping your discs with orgiastic pleasure while searching for flints to  subjugate (or words like that) with your tubeless tyres - and I am sure you are far too nice and intelligent a bloke for that to be the case.

I too had a lovely ride, as reported elsewhere, on my 40 yr old contraption without the sophistication - it was great for me too (and I didn't need to use my drum brake!). I think that having had a great ride is perhaps more important than what you ride -although taking pleasure from the level of modernity or sophistication of your machine is part of the experience, no matter how you look at it (the best bike in the world is the bike on which you have the best ride in the world - could be an old heap of junk if the circumstances work that way).

[grams]

I don't recall as many riders having to stop in the past because their mechanically operated gears had gone wonky; there may be other things that have changed (such as the move to 11s) which may have caused problems to be more frequent but my finger of suspicion is pointed firmly at the Di2 systems as being the most likely culprit.

Am I right in understanding that every time a rider has a bike problem, you're blaming it on Di2, whether or not it was a Di2 problem, and whether or not the rider was even using Di2, and then using this as evidence against using Di2?

[mattc]

On topic - it seems that the Di2 "crash mode" caused major problems for George Bennet yesterday at the foot of the Zoncolan. NB he didn't crash, but it cost him a lot of time as riding the Zoncolan in the 11 tooth sprocket is just not possible.

I'm not meaning to stoke the flames here - Di2 clearly has a place for certain riders - but the interview by the Telegraph Cycling Podcast with Bennett is quite something. He was VERY miserable! He was having a great Giro, high up on GC.

[Brucey]

Am I right in understanding that every time a rider has a bike problem, you're blaming it on Di2, whether or not it was a Di2 problem, and whether or not the rider was even using Di2, and then using this as evidence against using Di2?

that would be too easy.  Little clues like the rider being stuck in the wrong gear entirely, on a bike with no gear cables tend to give the game away....

one of the many incidents I recall was a few years ago when the ToB went through Keswick. There were two riders in a chasing group and one of them went for another gear at the back. P-twang went his electric RD, right into the spokes. This was a race-altering event and I saw it on live TV, but it didn't make the highlights show despite being pivotal to the events of the day's racing.

cheers

[Ben T]

Am I right in understanding that every time a rider has a bike problem, you're blaming it on Di2, whether or not it was a Di2 problem, and whether or not the rider was even using Di2, and then using this as evidence against using Di2?

that would be too easy.  Little clues like the rider being stuck in the wrong gear entirely, on a bike with no gear cables tend to give the game away....

one of the many incidents I recall was a few years ago when the ToB went through Keswick. There were two riders in a chasing group and one of them went for another gear at the back. P-twang went his electric RD, right into the spokes. This was a race-altering event and I saw it on live TV, but it didn't make the highlights show despite being pivotal to the events of the day's racing.

cheers

My personal opinion is that the idea of relying on a spring to pull a cable back through its housing is fundamentally flawed for any sort of bike that's used by a non-pro - i.e. used in all weathers and not necessarily serviced literally after every ride. It may work well for lots of people but I don't consider it reliable enough.
I've personally written off the idea of a cable actuated derailleur for any bike on which I do any sort of serious event due to empirical observation, from two incidents.
One being PBP in which the shifter cable became frayed. Luckily the mechanic at Brest was able to change it but if I hadn't had that luck it could have been ride ending - he said it probably had another 100km until the few remaining strands snapped through.
Second was on a commute when a gunged up cable was too much friction for the shifter, and the shifter itself (SRAM) snapped.
I am happy to trust the rohloff shifter which is a sealed system, both cables are hand actuated and the same thickness as a normal bike's brake cable (in fact the inner is brake cable). I'd also be happy to trust Di2. But I personally think the idea of relying on a spring to pull the cable back through is fundamentally flawed. The knock on effects of the spring not being strong enough are that you have to make the cable thin and reduce the amount of outer to reduce friction as much as you can, which leads to problems with ingress.
I only use a cable derailleur on the utility bike but it seems to work well on that I think largely because it has only got 6 sprockets, I rarely ride it in the wet, and failure isn't as much of an annoyance as it would be on an audax.

[Brucey]

the failures you think are unacceptable fall firmly into the 'easily preventable, lack of basic maintenance' category.  Anyone with that kind of failure ought to get less than the level of sympathy that (say) a puncture would engender, if they were riding around on knackered tyres that were of the wrong type.

As I mentioned upthread, there are many failure modes in a Di2 system. Professional mechanics don't seem to be able to make it work reliably; in fairness maybe they don't yet have the right skill set, but I don't think that is the full story; I think the technology is just not well suited to the application.

cheers

[zigzag]

one rider have had his rear mech cable snap on a 300k audax i did last saturday. after a few swear words he finished the remaining 240k on two gears without any drama, averaging 32kph with the front group. people tend to over-react when the gears stop working when in reality the bike is still very much rideable.

[Brucey]

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

[grams]

one of the many incidents I recall was a few years ago when the ToB went through Keswick. There were two riders in a chasing group and one of them went for another gear at the back. P-twang went his electric RD, right into the spokes. This was a race-altering event and I saw it on live TV, but it didn't make the highlights show despite being pivotal to the events of the day's racing.

And how on earth could that possibly be caused by Di2?

[Hot Flatus]

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.

[mzjo]

We have been at this a little while now and as far as I have been able to learn the Di2 failure modes seem to be entirely related to either cabling or batteries (sorry, accumulators) and reprogrammable electronics. All of that should be fixable by sensible installation, access to components and regular use. Which means that all the regular users, who find this equipment very reliable, have already mastered the steps necessary to keep it running reliably. (After that one can argue about incompatibility between versions but that applies already to mechanical systems and is more a matter of commercial strategy than technical necessity).

There is a small point when I read about the need to update firmware, connect to the contraption by Bluetooth, program the Garmin or whatever. All that may be clear and obvious to the technocrats but it is completely incomprehensible to those of us for whom a Canbus is a large red thing advertising australian lager. I am convinced that at the first need to correct the beast I would be able to so completely break it that no LBS could ever repair it (although a television repairman might  )

That leaves the two bikes out of three that J tells us will linger in the back of sheds. These bikes (and the 5 out of 10 that go out only a couple of times a month) will come out with the batteries flat, the firmware out of date, the hydraulic brakes seized and the sealant in the tubeless tyres dried up solid. That makes them unusable for the average gorilla who by applying WD40 and immeasurable brute force and ignorance to a mechanical system in the same state will at least end up with something capable of going to the pub or fetching the bread when absolutely necessary. That's my thought on hi-tec bikes for everyday use.

[Samuel D]

On topic - it seems that the Di2 "crash mode" caused major problems for George Bennet yesterday at the foot of the Zoncolan. NB he didn't crash, but it cost him a lot of time as riding the Zoncolan in the 11 tooth sprocket is just not possible.

I'm not meaning to stoke the flames here - Di2 clearly has a place for certain riders - but the interview by the Telegraph Cycling Podcast with Bennett is quite something. He was VERY miserable! He was having a great Giro, high up on GC.

For those interested, that brief interview starts at about 22:55 in this podcast. He’s not as miserable as I would be if my pay for next year had just dropped by the price of a nice house because a sponsor’s gadget glitched.

[Brucey]

one of the many incidents I recall was a few years ago when the ToB went through Keswick. There were two riders in a chasing group and one of them went for another gear at the back. P-twang went his electric RD, right into the spokes. This was a race-altering event and I saw it on live TV, but it didn't make the highlights show despite being pivotal to the events of the day's racing.

And how on earth could that possibly be caused by Di2?

the bloke riding the bike just pushed a button, the mech pushed itself into the spokes (quickly, and with maximum possible force, just like it was designed to do).  How was that not the fault of the system? It would have been checked for sure before the race and yet mysteriously managed to do something different at exactly the wrong time. Faults with mechanical gears are not unknown but are sufficiently rare that they draw comment; who can forget Andy Schleck's FD debacle in the 2010 TdeF?

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.....

Bikes with mechanical shifting do not usually have the gear cables routed through the stem and normally look quite different from ones with electronic shifting. You can normally tell quite easily in a head on shot of the lead riders in the peloton  if there are Bowden cables for the gears or not.

When a bike is broken at the side of the road you generally get a rear view of it. Mechanical shifting invariably has a stiff loop of gear cable housing by the rear mech which is of course a different shape too. It is not difficult to see the difference. Di2 bikes have a floppy loop of skinnier wire near the rear mech (one of the faults is that this loop needs to be there else the mech can't swing back to let the wheel out, but is vulnerable to getting snagged and damaged).

When Di2 was first introduced a lot of bikes had external battery packs which were a dead giveaway even in a long shot. These days the batteries are more likely to be hidden but even so it isn't difficult to see the difference in the event of a breakdown.

Maybe you need to buy a better TV or something...

cheers

[grams]

the bloke riding the bike just pushed a button, the mech pushed itself into the spokes (quickly, and with maximum possible force, just like it was designed to do).  How was that not the fault of the system? It would have been checked for sure before the race and yet mysteriously managed to do something different at exactly the wrong time.

Di2 mechs have physical limit screws, exactly the same as mechanical ones. There is no way for the electronic part of the system to shift beyond the limit screws into the spokes.

Unless of course the hanger is bent or some other physical damage to the mech. How would a mechanical one have done better in the same situation?

[Ben T]

the failures you think are unacceptable fall firmly into the 'easily preventable, lack of basic maintenance' category.  Anyone with that kind of failure ought to get less than the level of sympathy that (say) a puncture would engender, if they were riding around on knackered tyres that were of the wrong type.

As I mentioned upthread, there are many failure modes in a Di2 system. Professional mechanics don't seem to be able to make it work reliably; in fairness maybe they don't yet have the right skill set, but I don't think that is the full story; I think the technology is just not well suited to the application.

cheers

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.

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.
In contrast to a derailleur where you would be forced to be in the hardest gear.

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

[Hot Flatus]

the bloke riding the bike just pushed a button, the mech pushed itself into the spokes (quickly, and with maximum possible force, just like it was designed to do).  How was that not the fault of the system? It would have been checked for sure before the race and yet mysteriously managed to do something different at exactly the wrong time.

Di2 mechs have physical limit screws, exactly the same as mechanical ones. There is no way for the electronic part of the system to shift beyond the limit screws into the spokes.

Unless of course the hanger is bent or some other physical damage to the mech. How would a mechanical one have done better in the same situation?

Quite.

Of course anybody with any actual knowledge of Di2 knows that