Shimano Di2 Review- long term group test report

Discuss light weight issues concerning road bikes & parts.

Moderator: robbosmans

Post Reply
User avatar
Posts: 2947
Joined: Wed Aug 23, 2006 9:11 pm
Location: People's Republic of Boulder

by coloclimber

Shimano Di2 Review- long term group test report

I’ve used Shimano Di2 for almost 6 months now and its time for a full blown review on its function as a groupset.

Short version- It works. Recommendation: Sell everything you own to make it happen. (I sold framesets, a Super Record 11sp grouppo, a Chorus 11 mini grouppo, multiple Campagnolo wheels and cassettes to make it happen on 2 bikes for me. That’s saying something for a lifelong Campaphile.)

Long version-
Here is what I did with the group-
The group was trained on, raced on (using that term liberally) in the mud, sand, grass, snow, paved roads and dirt-


The drivetrain was subjected to the elements and thoroughly abused-

The group was moved between multiple bikes-

Wiring was internalized-

Wiring was externalized a couple of times-zip ties, wire covers...

The group was tuned-

The group was hacked for my rides-

Another group was hacked for a friend’s ride-

The worst thing that happened- The Di2 rear derailleur broke when the RD hanger snapped in peanut butter mud. I wasnt shifting at the time and I don't actually know if it was a chain, derailleur, wheel, alloy hanger problem or what. It happened to me earlier in the year on a different bike with Chorus 11 so no RD is immune. I dont' blame DI2 but the cost of replacement had me scared when it happened. I ended up fixing the RD MacGyver style so it still worked but Shimano ended up warranting it. Replacement was not a given since I don't know if it was a manufacturer defect (for me it depended on who called the warranty in) but in my experience, Shimano seems to want to support the high end groups.

Not so bad things happened- the wire covers lost their stickiness and the wires hung loose. The zip ties cut into my frame paint. The front junction wires can look messy.

I used different chains (KMC, Shimano), chainrings (FSA, Shimano, Stronglight and SRAM), chainring sizes (36,38,39,42,46,50,53), cranksets (7900, SRAM), cassettes (7900, 7800, SRAM), and chain lube (thin and thick).

I regularly sprayed the group, battery, junctions, derailleurs, wires etc down with a garden hose and brush. I even used a power washer once after a particularly muddy CX ride. I did not experience any issues with water intrusion.

This review is not- a fluffy feel good report based on a one time ride around the block in dry sunny Nevada. I rode the group without regard to its cost and tried to get it to fail- I don’t keep the top shelf stuff for only good nights. There were no sponsorship $s involved, no animals harmed and Shimano didnt give me any free sh!t for this review. I paid for it all so if I don’t like something- I'm free to say so. Its also not a review of the aesthetics of the group or a head to head comparison with other groups. Its a straight up opinion on the durability and performance of Di2 after half a year.

Here is a breakdown of what I did NOT like-
The lever shape. SRAM has this one nailed for me and Campagnolo 11 is pure organic goodness in your palm. The Di2 levers ergonomics, if you can call it that, are too long and rigidly cut for my liking.

Levers- WTF was Shimano thinking- do humans have block shaped palms?

With the right bars, the pistol grip works and there are a few other good positions. I like the narrow width of the levers especially compared to 6700 and 7900 STIs. Its just the non-anatomical shape and length that are bothersome for my hands.

Drop a stem size? Hell no, I switched to shorter reach bars. The lever length is not a deal breaker.

The shift lever positions were an issue for CX racing. I had a few accidental shifts on the front derailleur (left lever) when dismounting, shouldering and running during CX races. The cause- My knuckles hitting the shift levers during dismounts/runs/remounts. In reality, its not an issue for road riding and for CX- it didn’t matter since I jumped back on and powered whatever ring the FD had shifted to.

Crankset weight- Even the pimp daddy Dura Ace carbon crank is a lead weight relative to the WW competition. 7900 cranks are worse. The phenomenal shifting with the 7900 chainrings, full group aesthetics and overall stiffness make it worth it to me to keep the 7900 crank on a non-WW bike. However, on a bike where every gram counts, I am using some decent chainrings, getting a stiffer crank and saving almost 200 grams for not a lot more dough.

Crankarms get scraped up easily-
With dual finishes- its prone to look like crap very fast.

External wires are ghetto- Dirt, zip ties, crowded cables at the handlebars… its harder to clean than traditional cables and is more unsightly. How far will one go to get rid of the wires?- see the Time link in my signature.

Battery-The external battery location under the cage doesn’t bother me at all. Having played around with it in adverse conditions, its completely retarded of manufacturers to mount the battery under the chain stay or BB where it will catch more road grime. The real problem is the total weight of the battery and housing and keeping that system out of the elements. Both of these are solved by putting the batteries inside the frame. That's the future of Di2 and what I did to my ride- internalized the batteries. Don't be surprised if PRO starts making a seatpost with internal Di2 batteries. Look for more system integration here.

The cost- I genuinely feared the replacement cost when the RD broke. Even at a discount, it would be very expensive to replace a RD. The cranks and brakes are very expensive and are components where you could save a lot of weight and/or dough if you went WW after market. The costs here is relative though compared to other groups and compared to a frameset or wheels. For me it was very expensive but I sold what I had to to make it happen.

What I loved-

The shifting of course.
Its like the hand of God reaches out to grab your chain and place it on the chainrings/cogs. I could rave here but will spare you and just say without a doubt its the best shifting groupset ever made. I've had every top group out there and Di2 crushes them all in pure performance. No, I don’t miss the natural clunks or multiple shifts with Campagnolo. Nor do I miss the tin feeling taps of SRAM. Di2 is quiet and works every time. I missed maybe 2 or 3 shifts over the course of this review- both were in muddy races where I was cross eyed and couldn’t click a mouse to save my life. My fault or Di2’s fault?- who know and who cares. It was remedied in an instant. Multiple shifts- how fast can you click your mouse? What I found is that Di2 excels when ridden hard. Standing front chainring shifts under full power- no problem. A sandy mess- don’t sweat it, stay seated and push through it while your fellow racers are running. Di2 is a monumental benefit for the rigors of CX and lets you think about whats important on the road. I didnt spend any mental energy worrying about cross shifting or trimming the RD. It doesn't go out of alignment, doesn't need to be re-tuned, trimmed or lubed. With the ever tightening clearances and different cable thicknesses these days, its a refreshing relief not to maintain and worry about that kind of crap.

The chain-
Its hard to get excited by a chain but this asymmetrical, lightweight wonder is an easily overlooked, integral part of the system. Its quiet and works. After a pounding and not as many regular cleaning as I woudl have liked, its time for a replacement. Cost of the chain isnt so bad so bi-annual is something I can live with.

7900 brakes-
The Clash would be proud since these babies ROCK. I wont go back to WW brakes. If you are a buck 20, live in Kansas and don’t get over 30 mph on any ride- by all means try Zero G’s, but for real modulation and stopping power- you cant go wrong with the 7900 calipers. I used Shimano for carbon pads, Bontrager cork pads and standard Shimano pads and came away in awe of the calipers each time. Easy to swap pads too. The barrel cable adjusters are really big and easy to find while riding. The quick release is pretty small but still easy to operate at cruising speeds. Weight is the only downer on the brakes but again, something I can live with for the performance trade off.

7900 calipers are perfect for fast, twisty, wet, sandy, off camber descents- common place where I ride.

7900 Cassette-
Its lighter than 7800, its quiet, comes in a lot of sizes and works. For training, winter riding, or CX racing- I am going to use an Ultegra cassette for more durability.

Other thoughts-
Assembly- I am a DIY kind of guy and Di2 set up is not difficult. Shimano's web tutorial and power point presentation is awesome for first timers. Even Park Tool has detailed instructions on their site. I have installed Di2 a few times now and its not tricky. It its important to follow the instructions though and take your time the first set up. By all means- use the cable puller tool and dont just yank on the wires to remove them from junctions or derailleurs.

Break in period- There isnt the traditional cable stretch and readjustment period. Once its set- its set. Changing wheels may require a tweek at the junction to find the best shifting but maybe I was just playing around with the adjustment buttons since the shifting was actually good.

Tips and tricks- I found it best to stay in the Shimano family for drivetrain parts- chain, cassette and rings. Thinner lube and more frequent chain cleanings keep it smooth and quiet. Its not worth tuning the rear derailleur, the real weight savings is in the battery and holder. Its not rocket science to cut and splice the wires either for that clean look. The Shimano sticky wire liners don’t last long and zip ties look ghetto- internal is the way to go with the wires and battery. If you do stay external with the wires- spend some the time it takes to make it look and stay clean. Adjust the RD so that the derailleur can move farther out (towards the dropout) than your smallest sprocket to allow for different wheel and cassette sizes.

Common misconceptions- The battery just hit 50% after 5 months of use in through winter months. Its way over designed. Bi-annual charging is way less maintenance than lubing a chain weekly or pumping up the tires before each ride.
A wireless system wouldn't necessarily be an improvement- just make the wires disappear by routing them internally. Its great to see more frame manufacturers offering this option.
Its easy to find the shift buttons in the winter with full fingered gloves- just know where to shift.

Bottom Line
Di2 works so well as a system that I converted to Shimanoism. I have learned to overcome or just fix the issues I don't like. Di2 didnt make me a better rider or wont win me any races but its fun to use, reliable, durable and it just plain works without fuss. The group is a winner in my book. :thumbup:

I would like to give a huge thank you to Madcow at Fairwheelbikes for his help, tips, tricks, insights, labors of love and general attitude when it came to my seemingly endless array of questions. You are the man. :beerchug:
-Deacon Doctor Colorado Slim

User avatar
Posts: 1075
Joined: Sat Mar 27, 2004 11:00 pm

by Dr.Dos

Simply an awesome review.

Head and shoulders better than anything I read here and mostly any forum I might add.

by Weenie

Visit Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

Posts: 140
Joined: Fri Jan 15, 2010 11:57 pm

by McJohnson

:thumbup: Thumbs up coloclimber! You are doing some quite nice things... :thumbup:

Posts: 84
Joined: Sun Jan 03, 2010 6:27 pm

by gwilliams

Great test, reassuring feedback on di2 :thumbup:

User avatar
Posts: 1063
Joined: Tue Feb 02, 2010 4:22 pm
Location: Brooklyn

by CBJ

Very good review - I am really impressed with Di2 and it will be interesting to see the next versions/groups too.

User avatar
Posts: 879
Joined: Thu Apr 08, 2004 3:31 pm
Location: Hollywood

by ElDuderino

tip of the hat, coloclimber! Really enjoyed the photos, and I'm now even more stoked for the future of the electric stuff!

User avatar
Posts: 2832
Joined: Sat Apr 16, 2005 6:08 pm
Location: Boulder, Colorado

by lancejohnson

Dude, tidy up that freakin bar tape and then you can complain about aesthetics - not before.

it's a running joke, never mind.

I like it, I love it. Now I just need to built that bike with the internal routing and you can help me wire it up...

"Organization is for the simple-minded, the Genius controls the chaos." - Jens

User avatar
Posts: 4484
Joined: Wed May 18, 2005 6:24 pm
Location: BELGIUM

by strobbekoen

Nathan my friend, you are one thorough and detailed person :thumbup:
Interesting about the batteries. Wonder why it's over designed ?

Doctor Who
Posts: 74
Joined: Sat Feb 02, 2008 5:57 pm

by Doctor Who

Man, now I wanna sell all my stuff and go Di2.

Thanks for the great review.

User avatar
Posts: 5682
Joined: Thu May 04, 2006 4:43 pm
Location: Wherever there's a mountain beckoning to be climbed

by HammerTime2

coloclimber wrote:The battery just hit 50% after 5 months of use in through winter months. Its way over designed. Bi-annual charging is way less maintenance than lubing a chain weekly or pumping up the tires before each ride.
How many miles did you put in over those 5 months? Any idea how many front shifts and how many rear shifts? It would be kind of cool if it kept track of the number of shifts - perhaps you can hack it, or are you more a HW than a SW guy?

Also, don't assume that the percent remaining figure is correct. On my cell phone, 50% remaining is really somewhere around 25 to 30% remaining, even accounting for auto shutdown when the level gets very low.

Why did Shimano overdesign the battery? Because they didn't want a lot of people "breaking down" and getting stuck on the road with dead batteries, and incurring the bad reputation which would go along with it. Plus, does Shimano really know how much people shift? I suppose they have studies of that, but who knows how accurate that is, and having electronic shifting might increase the amount of shifting, but by how much? So better safe than sorry for the first iteration. Maybe Shimano will redesignate the original battery as the touring or training battery, and come out with a smaller, lighter "racing" battery, for which they can charge more.

Posts: 1484
Joined: Sat Oct 10, 2009 7:13 am
Location: Glendale Gary

by tonytourist

Great review, very thorough too :beerchug:
I'll have to save my pennies :lol:

Posts: 956
Joined: Tue Dec 16, 2003 4:24 am

by limba

Nice job. Thanks for the detailed review.

User avatar
Posts: 1958
Joined: Sun Apr 15, 2007 5:10 am
Location: South Florida

by dgasmd

Nicely done. :thumbup:

User avatar
Posts: 1736
Joined: Thu Jul 06, 2006 5:53 pm
Location: The Surrey Hills

by corky

Real world testing.... fantastic.

Electronics it's the future.

Posts: 111
Joined: Sat Dec 05, 2009 6:48 am

by dandancast

Thanks for posting it. Love the reading. :thumbup:

by Weenie

Visit Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

Post Reply