Di2 - A technology too far?

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mattheus
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Re: Di2 - A technology too far?

Postby mattheus » 30 May 2019, 12:27pm

thelawnet wrote:
Cugel wrote:Here's a starter:
(a) Replaceable bearings, gear parts, brake parts; et al, so the whole thing doesn't have to be binned when worn.


There are quite a few bikes with disposable parts. Some very pricey ones at that. For the manufacturer and retailer repairability isn't necessarily a good thing, if you can design something that breaks expensively and can persuade the customer to replace it. Arguments about waste and so on aren't likely as credible as they seem given the vast amounts of waste produced by the typical human, an extra brake here or cassette there isn't a significant extra burden.

We've been here before, quite recently! [see some tedious thread about "hypocritical" campaigners ]

Why can't we at least TRY to reduce waste - if not on a Cycling forum, then where? Does someone else throwing a load of plastic away stop YOU from being a responsible recycler?

have you heard the saying that starts "look after the pennies ..." ? try using a similar idea wrt waste :)

Ellieb
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Re: Di2 - A technology too far?

Postby Ellieb » 31 May 2019, 9:58pm

I seem to recall we have been here before. Ultimately almost every technological ‘upgrade’ will have disadvantages as well as advantages. The particular demographic on here seems to only ever see the problems involving new tech. I can’t help feel that if the internet had existed when pneumatic tyres were introduced there would be bleating on here about ‘punctures’.

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Lance Dopestrong
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Re: Di2 - A technology too far?

Postby Lance Dopestrong » 31 May 2019, 10:11pm

I'm of that demographic and I don't see a problem with it. I admire it as the technological marvel it is. It's simply not for me.
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Brucey
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Re: Di2 - A technology too far?

Postby Brucey » 31 May 2019, 10:13pm

Ellieb wrote:I seem to recall we have been here before. Ultimately almost every technological ‘upgrade’ will have disadvantages as well as advantages. The particular demographic on here seems to only ever see the problems involving new tech. I can’t help feel that if the internet had existed when pneumatic tyres were introduced there would be bleating on here about ‘punctures’.


see my post upthread about displacive technologies; these are (arguably) real progress.

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horizon
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Re: Di2 - A technology too far?

Postby horizon » 31 May 2019, 10:28pm

Ellieb wrote:I seem to recall we have been here before. Ultimately almost every technological ‘upgrade’ will have disadvantages as well as advantages. The particular demographic on here seems to only ever see the problems involving new tech.


To be fair to this particular demographic, Di2 crosses a threshold in that electronics are used in the operation of the bike itself. Whether you think that's a good thing or not is what's being discussed here. The discussion most probably reflects, as you say, the demographic. BTW I think Di2 is different from GPS, LED lights, smart phones, power monitors etc.
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iandriver
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Re: Di2 - A technology too far?

Postby iandriver » 1 Jun 2019, 12:03am

Technologies often take time to come properly good. I stated upthread I want to like it. When it works, I'm sure it's great to use. The one I want to work the most is the 11 speed Alfine version, the one you never hear about. Typical.

I'm a serial abuser. My kit isn't bought as future collectables. I expect it to do a hard job of work. None of these scream Di2. Not yet.
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Brucey
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Re: Di2 - A technology too far?

Postby Brucey » 1 Jun 2019, 9:05am

FWIW the 8/11s Alfine Di2 (and the so-called 'cybernexus' 8s) uses a potentiometer to 'resolve' the position of the gearchange mechanism. This sort of thing is very commonly used in all kinds of servo controlled mechanisms. The advantage is that if the mechanism requires variable force to be overcome, the servo motor doesn't care; so long as the resolving element is indicating the correct position, the motor will always see a driving force towards the correct position.

The motor, resolving potentiometer and various gears etc are enclosed in a housing that is attached to the rear hub in place of the cassette joint. AFAICT this whole approach is both very clever and fundamentally flawed;

a) the housing isn't entirely sealed (and probably can't ever be)
b) the housing contains mostly fresh air (so will have to 'breathe' with temperature/pressure changes)
c) the housing doesn't have drain hole at the bottom
d) the most sensitive gubbins in the housing is placed in the upper half

in the test lab and/or in dry weather I can see this whole arrangement working OK. In real UK (commuting) conditions I think it is liable to be terminally unreliable. There is no way on this earth that water won't get into the housing and/or condensation won't form within it. Once water gets into the housing it won't drain out; more condensation will form in the top half of the housing (where the most sensitive gubbins is to be found) and it doesn't take a genius to see that this will ruin it. It also doesn't take a genius to spot that if the bike is turned upside down when there is water in the housing, the gubbins will get water sloshing around all over it. Once the resolver goes intermittent or fails, the shift servo could do anything. If the motor fails it will do nothing. Ever had a radio with a crackly volume control? That is a failing potentiometer; if the same thing happens in you shift servo it won't work properly.

All this lot is attached to hubs that are themselves not 100% reliable in UK conditions unless they get special treatment. At least the hubs have a fighting chance; they are lubricated with grease that has some corrosion resistance (rather than none). The insides of the shift servo are not treated with anything.

The 11s hub is very clever and is probably stronger than you might expect given the problems that were originally encountered. But a Rohloff it ain't; it isn't as efficient as it could be, and (if you are a remotely strong rider) you will probably notice that it feels distinctly 'spongy' in many of the lower gears. The Di2 system doesn't address any of these things; whilst it is working, it will probably select gears more accurately/quickly than a mechanical shifter. But when it screws up, it will be worse than useless. If you are a strong rider and/or you want to ride in all (UK) weathers using a shimano IGH, I'd suggest the Alfine 8 but with careful attention to the shift cable and improved lubrication inside the hub.

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Gattonero
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Re: Di2 - A technology too far?

Postby Gattonero » 1 Jun 2019, 10:35am

Ellieb wrote:I seem to recall we have been here before. Ultimately almost every technological ‘upgrade’ will have disadvantages as well as advantages. The particular demographic on here seems to only ever see the problems involving new tech. I can’t help feel that if the internet had existed when pneumatic tyres were introduced there would be bleating on here about ‘punctures’.


Too right!
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since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

iandriver
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Re: Di2 - A technology too far?

Postby iandriver » 1 Jun 2019, 10:47am

Gattonero wrote:
Ellieb wrote:I seem to recall we have been here before. Ultimately almost every technological ‘upgrade’ will have disadvantages as well as advantages. The particular demographic on here seems to only ever see the problems involving new tech. I can’t help feel that if the internet had existed when pneumatic tyres were introduced there would be bleating on here about ‘punctures’.


Too right!


And possibly quite rightly in the very early days. I doubt the earliest incarnations were anything like what we know today. Most of us have gone away from leather brake blocks and rod brakes. The benefits need to be clear for me though, and just yet, it isn't IMHO.
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Gattonero
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Re: Di2 - A technology too far?

Postby Gattonero » 1 Jun 2019, 10:51am

Benefits for a given technology are all in the hands of the user: if you're riding 1/4 mile flat to the supermarket, any single-gear old clunker will do, no need for electronic gears.
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

reohn2
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Re: Di2 - A technology too far?

Postby reohn2 » 1 Jun 2019, 11:03am

For me the cost far outweighs it usefulness and as Iandriver says it's early days yet for reliability and durability.I suspect there'll be a few steps before it can get close to cable systems.
I suspect in outer Mongolia there'd be tears before bedtime,but then I suspect any self respecting tourist wouldn't risk it,sportive types employing the 'new golf' approach to their cycling may go the whole hog.
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Gattonero
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Re: Di2 - A technology too far?

Postby Gattonero » 1 Jun 2019, 11:16am

reohn2 wrote:For me the cost far outweighs it usefulness

For you, and so is for me, but for some others may be useful. As long as it's an option and not something that is force to, I don't have a problem with it.

reohn2 wrote:and as Iandriver says it's early days yet for reliability and durability.

You both have data on hand, i.e. followed racers and groups and seen several dozens, or just speculating?
Truth is, the only problem you really have is when installing a new component, that often requires to update the firmware(s) and that's not practical when on the field (ask me how do I know)

reohn2 wrote:I suspect in outer Mongolia there'd be tears before bedtime,but then I suspect any self respecting tourist wouldn't risk it,sportive types employing the 'new golf' approach to their cycling may go the whole hog.

You suspect a lot, maybe should just relax a bit more? Self-respected long distance riders are doing the London to Istanbul with electronic gears, and I havent't heard of people crying because of it (maybe other factors), and so are using some people riding those crazy long unsupported races across America.
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

iandriver
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Re: Di2 - A technology too far?

Postby iandriver » 1 Jun 2019, 12:28pm

Gattonero wrote:
You both have data on hand, i.e. followed racers and groups and seen several dozens, or just speculating?
Truth is, the only problem you really have is when installing a new component, that often requires to update the firmware(s) and that's not practical when on the field (ask me how do I know)

Repeat of the blog post from a well respected race blog.
Even the feeling in those circles is the gains are minimal and the downsides severe. http://inrng.com/2019/04/the-moment-par ... x-was-won/

Got the data to prove its reliable, or just speculating?
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Brucey
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Re: Di2 - A technology too far?

Postby Brucey » 1 Jun 2019, 12:57pm

most of the professional field are now using Di2 type gears (or similar). In the Giro this year there have been multiple problems with gears every single day including on yesterday's stage where it cost the chap that came second any chance of the stage win. I don't know exactly how many problems there have been or if they can all be laid at the door of Di2 but a reasonable estimate might be one a day. In a field of ~100 riders that suggests that the mean time between failures is ~100 days competition riding, even with (one would hope) the highest levels of maintenance.


Perhaps a computer expert would consider that 'miraculous reliability' but from where I'm sitting it is rubbish. Part of the trouble is that if you have a conventional gearing system there are things you can do, both in the way the controls are worked exactly, various barrel adjusters etc and right up until the cable actually breaks you are likely to have some control rather than none over the derailleurs. If you are just pushing buttons there are fewer options.

The bloke yesterday unshipped the chain from the front; IME you can work around this (sometimes without dismounting) and carry on, with most other gear systems. But with Di2 maybe not.

I'd love someone to be compiling good statistics about this; in other sports (eg Golf) you can have every statistic going. In cycling this hasn't happened yet.

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kwackers
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Re: Di2 - A technology too far?

Postby kwackers » 1 Jun 2019, 1:31pm

Brucey wrote:Perhaps a computer expert would consider that 'miraculous reliability' but from where I'm sitting it is rubbish.

Computers in general are stunningly reliable. Every car, motorbike has several. Aircraft have many tens of them and most folks houses probably have dozens to hundreds, the vast majority are completely trouble free far outlasting the devices they're fitted to.

DI2 is a consumer product, no idea what the actual system the pros use but I bet it's trimmed weight wise down to nothing.
The failures are almost certainly likely to be failure of the mechanical bits rather than the electronics and probably related to the weight saving.
Look at how often F1 cars fail compared to the consumer car fleet.

Of course bicycles are inherently simple, we accept their mechanical limitations because they're "easy to fix" and we'd continue along that path even if the MTBF of computer controlled gears was longer than the life of the bike - because "well if it fails I can't fix it".

I've built a new commuting e-bike based on my ideas of why my old tourer was a bit crap.
With close to 1000 miles a month and little time to properly service it (other than squirt oil at it) I went the hub gear route so I can get the chain tracking right, use 1/8th chain, fit proper chain guards - and I also fitted DI2.
Now I'll admit it's an experiment, but transmission issues for that sort of mileage particularly in the winter with little servicing are often enough - even if it's just a clobbered chain, worn derailleur or knackered cables.

Certainly the DI2 makes for positive gear changes and my hope is that the positive engagement and guaranteed aligned gears will counter the combined energy of both me and the motor and reduce wear on the hub.

As I said, it's an experiment but if it works as I hope then it'll be a step towards a (e)bicycle which makes a decent long distance commuter.
IME that's the biggest problem with bicycles, over middle distances they're just not that reliable and require far too much servicing.