UKC

I'm thinking of upgrading from an old Ultegra 10 speed to 11 speed.  Is Di2 worth it?  Do the benefits outweigh the nagging doubt of a flat battery with a big hill between me and home?  How often to daty need re-charging?

Depends what you're doing with it, but for the average rider I'd argue it's not worth the outlay, you'd be way better off taking a week off work and having a training camp abroad (same for basically any bike upgrade once you've a decent enough bike).

If you're crit racing where you need rapid - and 'secret' - gear changes regularly then Di2 makes more difference. A lot of pro's still ride manual over electronic gears unless they are crit racing, and all my strong mates ride without Di2 as it's cheaper to replace if/when you crash.

I think so. It’s certainly brilliant for racing. I wouldn’t go back to mechanical. It only needs charging about once every 3 months. 

Oh yes, worth it big time, I was a naysayer, the new bike has Di2 and discs, it’s bloody good.

What Mr Fuller said, with the exception that I'd spend the difference on upgrading the wheels.

For the average amateur rider, I don't see that Di2 makes enough difference to justify the cost and the components are very expensive to replace compared to the mechanical equivalents.

The only "casual" rider I've ever met that seemed to justify the cost was an old boy with such bad arthritis in his wrists that he could no longer operate a mechanical groupset.

However, it's your bike and your money, so if you want it, fill yer boots

And don't leave the battery sat charging at home when you drive to your first sportive on it...!

I'm a "casual" rider and love my di2 bike. I can't see me ever going back to a mechanical group set.

Is it worth it? Perhaps not but it is to me.

It has changed the way I shift gear, changing much more often than I used to. I like the way you can set it up so the cassette changes automatically when you change the front chainring. Changes well uphill at full power out of the saddle.

As a bonus an injured hand for the last few weeks meant I would have struggled to change gear on a mechanical group set but was fine pushing a di2 button.

Does it make a difference? No

Is it a fantastic luxury? Absolutely.

Got it on a bike last summer because it fell within my price range. Do not regret it - shifting always bang on (no adjustment when the cables stretch) and I haven't had it go flat on me yet - charge it once every three months or so. 

I love it compared to 105 groupset, much easier on a  long ride. I wouldn’t worry about battery life- I’ve done 600 miles since last charge and still showing 50% battery. 

They don't really go flat flat, well they do, but they go into self protection at a point so limit shifting, kind of like a limp mode, info here:

https://tempocyclist.com/2016/02/02/di2-battery-life/

Mechanical Dura-ace is a lighter shift than either ultegra or 105, so if you are upgrading consider that a useful upgrade in itself. Can't say I wouldn't di2 if I had the money to spare though.

last year when I’d just accidentally cut the cable in the housing while fitting my da group set (hello shop could I have another really expensive bit of wire please).  Then I pulled that through only to catch it and fuzz the coating off (hello shop could I have yet another really expensive bit of wire please) my friend messaged to say, di2, just saying.  He thinks he’s sooo funny.

Anyway, no I would’nt buy it.... I want etap.  Two brake cables and no other wires and you could carry a spare battery in your pocket not that this ever seems to be an issue for any of the elec groupsets.

Happy shopping.

toby

Trashed my 105 rear derailleur last week (jammed gravel, mashed jockey wheel, bent cage) miles from anywhere. Managed to take it apart and bodge a repair to get me home (with most gears working, albeit noisily). Replacement cost £30. Now if I'd had Di2, could I have repaired it in the field? Don't know. It would certainly have cost a lot more to replace (£170?). OK, rare event, but last week I was glad to be mechanical.

To your original question - is it worth it? Only you can judge, it's a very personal thing. Marginal performance improvement (over Ultegra mech groupset ) vs. more expensive/complex.

Thanks everybody

Some interesting and useful observations

The major benefit for me will be upgrading from a much older version of ultegra to the latest version and 11 speed - smoother shifting and closer ratios on an 11-28 cassette.  I can reuse my more recent 10 speed chainset so this would be a relatively low cost upgrade.  Di2 in comparison seems a much smaller improvement for much more cash so I'll stay mechanical

I think it's also worth asking "Ultegra Di2 or mechanical Dura-ace?"  The brakes are storming and shifting is light.  Dura-ace is more expensive for a reason (e.g. bearings in the brakes rather than bushes)

I have no real experience of Di2, but I have a bike with DA9000 and a newer bike with 105, the difference between the shifting on these two machines is massive. Not all mechanical groupsets are equal, obviously the DA kit costs three times as much as the 105.

Good choice.
As you know I've been running cycling tours in Provence for almost 15 years now. The only times in the last few years where someone's day has been ruined by a mechanical problem is when their electronics decide to pack in. (I'm also refering to SRAM eTAP here too)
We can fix 99% of problems at the side of the road but when the electronics don't want to play they don't want to play.
Had a guy over from Texas last month with SRAM eTAP on a beautiful Giant Propel. His eTap packed in on the 2nd day and because we were nowhere near a dealer that was it. We tried everything to no avail. He was gutted - the expense of shipping his bike over then having to rent one to use for the rest of the week
Another guy the other week had to do about 75km of a ride in the small ring at the front. Not funny when we're going through and off at 40kmh

I have DURA-ACE R9100 on my new bike and it's the sweetest thing I've ever used. Always said, the day I have to plug my bike into a laptop is the day I stop cycling

Enty

Why not go the whole hog and buy an e--bike? Genuine question. 

If you're happy to use electricity to help you ride your bike then why not use more electricity to help you ride your bike?

That's the nub of it for me. There's a transition with Di2 that takes away from the beauty of a purely mechanical system. I say that as an electronic engineer!

What appeals to me is the idea of a single gear bike with electric transmission using a pedal generator and a motor on the wheel.  No storage in the system, so you still feel demand on the pedals, but vastly reduced moving parts and mechanical noise, and never again trying to repair a chain in the middle of nowhere using a screwdriver and two rocks.... 

or even better a direct drive?  it was called the Penny Farthing

I guess the point is that you *can* fix a mechanical drivetrain with a screwdriver and two rocks (as I did last week). Good luck fixing an electronic system (probably littered with lots of features/complications that some designer though was a 'cool' idea) in the field.

I think I have the same stance - for me a bike should be purely mechanical and, as part of the aesthetics, all the workings are on display.

I'm happy to draw a line at the electronic detachables like watch, gps, lights because they aren't actually part of the physical act of riding the bike.

Plus electronic shifting is too expensive for me

I see the spectrum as “Electric Drive > Gears > Penny Farthing” - done right, electric drive would allow you to feel a direct connection to the power demands but with a continuously variable transmission that has none of the suck factors associated with geared systems.  Gears are an imperfect attempt to give a responsive infinitely variable ratio between rider and wheel.

I never used to mind gears in a car or a motorbike but now I’ve got an EV my perceptions have changed dramatically.  Full power and instant torque with no perceptible lag, no clunking noises and no discrete gearing with pauses to change gear - subjectively everything sings along to a much better tune.

I don’t know that an electric transmission zero storage bike would ever catch on for good reasons covered in replies to me.  Still, it’s something I really want to try.

In reply to Marek:

For sure.  Done well a permenant magnet alternator, power converter and permenant magnet motor should be pretty bomb proof - very few moving parts and reliable power electronics.  Much harder to fix but also much more reliable than most gear system.   

Vastly reduced efficiency as well say 10% each for motor/generator? Chain more like 2 - 5%.

Honestly, i was always the same, then i had the chance of a good deal on a new bike with Di2, there is no way i would go back now, sure if i was still racing then it would be mechanical all the way but Di2 is a pleasure to use, it changes so much better and under full power on a climb its so much easier to get a change, the auto trim of the front based on chain line is also a massive improvement over having to manually trim it when you go from low to high in the small ring, doesn't sound like a lot but all the small things add up to a much better experience, i also find the lever/hood shape better too, marginal gains and all that

Typical motor/alternator efficiencies are ~50-60% (each), so the overall efficiency is ~30% (compared to >90% for a standard drivetrain). You'd need to generate gut-busting 300W to keep up with someone doing a gentle100W on an ordinary bike.

I think that's the point you were trying to make? 

I suspect my 'full power' on a climb is a lot lower than yours, and in any case I'll be in the bottom gear and looking to change

thats NOT looking to change ...doh

If going from 10 to 11 speed you’d need to change the free hub body. this would work but there’d be a slight dishing ofset but shouldn’t be a problem 

11 speed cassette won’t fit on 10 speed free hub  but once you’ve changed the free hub to 11 speed the old 10 speed will fit on the 11 speed free hub with a spacer (that you get with the new free hub)

Long term its prob best to have the wheel rebuilt or the dish corrected at lease. That’s before you get into Di2. Me? old school- 8 speed claris on winter bike and 11 speed 105  on roadie.

I think racing is where the main benefits are. It’s just so accurate and reliable, much more so than mechanical, and it changes perfectly under heavy load. 

Thanks but my wheels are 11 speed compatible, they came with a spacer for my existing 10 speed set up

I'll bow to your greater knowledge on the numbers, and I rather conflated loss with efficiency - but yes that is the point I am making.