So I'm going to build a new bike and I can get either dura ace mechanical or Ultegra Di for the same price. What do you think?

If I weren't me, , I would go Di2.

2018 Roubaix Expert ordered and went with mechanical. Will forego the "ease, smoothness, self adjust" of Di2 in favor of no worry regarding battery, servo issues and servicing by me.

There are issues with both groups;

Di2:
-total power failure (broken/damaged cable).
-crash damage can damage the servo motor in the rear derailleur.
-you have to charge the bike infrequently (the horror!)

Cable-operated:
-total failure (cable can snap at the right radius bend in the shifter--a common issues with recent generations of STI shifters).
-crash damage can render the rear derailleur inoperative.
-you have to change the cables/housing infrequently (the horror!)

And so on... The point being that the differences are best left to personal taste, rather than reliability:

-some riders don't like the indistinct feel of shifting Di2--"clicking a mouse".
-cost to replace components, if they break (Di2 being more expensive, all else equal).
-satellite shifting options (Di2 only), or ease of changing handlebar configuration (shifters on aero bar extensions...).

You'll notice that I didn't include batteries dying on a ride...because you really need to ignore the system for it to happen. The junction box will flash a number of shifts before the front derailleur (the power hog of the system) is shut off, allowing you time to shift to an appropriate chainring to get home; the rear derailleur is still powered for a time afterwards, allowing you time to plug in when you make it home.

Completely personal choice. Mechanical Dura Ace, if properly adjusted, is every bit as crisp and precise as any di2 group. Charging the battery really is very infrequent. I think di2 is a good choice for beginners whom don't have a good feel for mechanical shifters. Seasoned vets can go either way and be happy.

Di2. No question.

Mechanical no question. Robotic derailleurs are overkill.

Will the Di2 parts all still work in 5/10/15/20 years time ? Most of the mechanical bits will, only the internal STI shifters are likely to develop in issue. The brakes and deraillers if they are not destroyed in a crash will last a looong time. And if you need cheap spares in a hurry, 105 and ultegra bits are compatible.

Who knows if Di2 spare parts will be available in 5/10/15/20 years ? My prediction is Shimano will eventualy, in the coming years, adopt wireless and leave the wired Di2 groups in the dust along with the customers. Just like they did with the first version of Di2 7970.

Agree.

Once you try Di2 you'll never go back.

The only people who don't recommend Di2 are those who have not tried it.



-Tim-

Except me who has owned 9000, 6870 and 9070 and i went back to 9000.

Di2 is grossly overated and overpriced IMO. The only stand out feature is the FD autotrim. Precise shifts in the rear is not a performance or game changer.

OP, have you heard of XShifter ?

It uses servo motors connected to cables to convert mechanical derailleurs to electronic to take advantage of the same features of Di2. Worth a look. It doesn't have the crazy price tag of Di2 but will do 95% the same thing. And it gives you the option to convert back to mechanical.

And it's wireless

It's still in development phase but should be available soon.

https://www.kickstarter.com/projects...less-smart-shi

Bike Gear Shifter for Wireless Shifting | Derailleur Gears

Timothy, I have tried it and loved it but out of the two choices the OP presented I would pick the Dura Ace. I would rather have the top end of a group rather than middle tier. If I had Ultegra, I would always want Dura Ace. Now if it was a choice between the two Dura Ace groups, mechanical or Di2, I would chose the Di2 but those weren't the choices offered.

I would go with DI2 for sure. I have tried 6800, 5800, 4600, 4500 .... they all shift well. I cannot imagine Dura-Ace would be exponentially different. A little smoother, a little easier, maybe ... but no night-and-day difference.

I'd like to try DI2 just to see ... from what I hear it offers versatility and functionality a little bit beyond mechanical.

That's an inaccurate supposition. I have Super Record EPS and it's not "game changing" by any stretch. It's nice, but my other Super Record mechanical bike is just as crisp, accurate, and efficient.

Having worked in a bike shop a bit after all this came out, I got to ride with it a bit. Aside from the issues which you would expect from new release stuff (then) it was super trick.

I personally chose to go with mechanical. One less battery to charge, much less to deal with issue wise.

Having been on group rides several times and witnessed either a rear derailleur failure or a battery issue where that person was stuck riding one gear 40mi home... i personally can't be bothered with that and would go mechanical Dura Ace and enjoy the weight savings.

Bling-Rich? Campag has an electronic pro race group too..

I can't go by that ... that is user error. if one time out of every hundred rides people couldn't shift, i think we'd see a product recall ...

I haven't tried it myself, only because I can't justify the expense right now, but if I buy anything new it's gonna have electronic shifting.

I haven't tried Di2, but I do know this: Chris Froome has his bike tuned up every single day by a professional bike mechanic. If that's not good enough, he has a van following him around with an identical back up bike all ready to go with it's front wheel already installed and tires pumped up and ready to go. During the Tour De France one topic of discussion was whether the peloton was right in holding up while he changed bikes because his Di2 shot craps. I wonder how many additional times that happened to riders who didn't happen to be the race leader and consequently attract a lot of attention.

I'm thinking that it's probably really, really nice when it's working right but I've lost patience with unreliable electronic gizmos. If that makes me a retro grouch, I'm OK with that. Given the choice between reliability and features, I'll pick reliability every single time.

I guess you are one of the types that peruse product reviews for the scientific analysis?

Jealous because DI2 doesn't fit on trikes.

(Kidding, but too good a straight line ...)

I'm thinking that it's probably been done.

Recumbent riders tend to be early adopters, tinkerers and not afraid to spend their money.

Sorry, I ride Campagnolo. Can't recommend either. Suit yourself, neither is the wrong choice

I have one of the original Dura Ace Di2 which is very nice and never let me down; however, I am getting a new bike and have selected the mechanical Ultegra group set. I own another bike with older Ultegra and it also shifts like a dream so I decided to save myself some money and go with the Ultegra group. If you want the Di2 go for it as you don't really have to worry about the battery unless you just ignore it. You may want to ride both, if you haven't already. I'm sure you will enjoy either.

This is true. Di2 no question. I've been riding mine about 10 weeks now and a quick battery check still shows solid green (50-100%). I don't think this thing is ever going to run down.