Shimano Ultegra 6870 Di2 11 speed install and early riding impressions….

I’ve been fascinated by the idea of Di2 from the start and have watched it with interest. However other than a short go on a Shimano Dura Ace 9070 bike on a turbo trainer, I’ve never ridden it.

When I built up my new NeilPryde Nazare/Alize test bike recently, it seemed like the perfect moment to make the leap to Di2. After some conversations with a few people including the good folks at Madison, I had bought myself a Di2 groupset.

Excited to be making the leap to Di2!

Excited to be making the leap to Di2!

I thought it might be interesting for people to see a little about how Di2 is installed and setup, so I took my camera for the build and took some notes to share with you. I’m no mechanic so my observations are pretty general rather than an instructional guide.

Internal Junction box and wiring

Internal Junction box and wiring

The first thing done was to run the connecting cables for the gear shifting through the downtube from the stem to the bottom bracket where on my frameset the internal junction box runs. Then the wires from the junction box to the front and rear mechs were installed as was the one for my external battery under the non drive side chainstay. In fact choosing the cables to connect the mechs and battery are really the only “tricky” part of deciding what you need to order. You need a cable from the each shifter to the junction box under the stem. You then need a cable to run from the top junction box to the bottom bracket junction box. Then cables from the bottom bracket junction to the battery and the mechs. Shimano sell the cables in a range of lengths, so it’s a matter of getting your tape measure out and working out what lengths you need to connect everything together.

Front mech install...

Front mech install…

Installing a lot of the components is exactly the same as a mechanical build – the brakes and brake cables, the cranks and bottom bracket (I went for a Praxis Works conversion bottom bracket to run my Ultegra crank in a PF30 frame).

Praxis Works Conversion Bottom Bracket

Praxis Works Conversion Bottom Bracket

Also the chain and cassette and even the rear mech mounts the same way as a mechanical one. The front mech is slightly different as there is also a bracing plate and bolt to stop the mech twisting under the significant torque the motor generates shifting between the front rings.

External battery mount being attached and connected

External battery mount being attached and connected

Once everything is installed on the bike, it was connected to a laptop to ensure that all of the electronic components each had the latest firmware. It is possible that if they don’t due to different timings of manufacture that they won’t work right away – checking and updating the firmware makes sure they’re all using the same software version. The laptop interface also gives you the opportunity to adjust how the levers work in terms of speed of shift or which buttons shift which gears. I left everything as standard except increased the speed of the shifts. Once the software was all up to date, Jack from Madison then set up the gear shifting.

Firmware checks as part of the build process

Firmware checks as part of the build process

Setting up the front mech was done with both front and rear on the inside cogs (so small ring at the front and biggest cog at the back). A Di2 mech over shifts and then trims back when it goes up onto the big ring, so setting the limits correctly is key. Once this has been done properly – it should just shift perfectly on an ongoing basis and does on my bike.

Close up of the correctly mounted front mech

Close up of the correctly mounted front mech

With the rear mech, again setting the limit screws is the first thing to do and once this is good, the shifting itself is adjusted. To do this you move rear cassette into the 6th of 11 gears (i.e. the middle gear) and enter the adjustment mode using the junction box at the stem. This is then your digital barrel adjuster that has 12 micro adjustment points in each direction from the middle – so 25 points of adjustment.

Chain going on....

Chain going on….

Pressing the gear shifters adjusts the gear shift position either up or down a fraction allowing you to really fine tune the shifting. Once that bits sorted – it’s done. It’s a simple but clever design and I think 25 points of adjust for the digital barrel adjuster seems amazingly precise.

Di2 Rear mech prior to indexing adjustments

Di2 Rear mech prior to indexing adjustments

Obviously one of the great things about Di2 is no cable stretch – so the gear shifting should stay bang on. I’ve done around 350km now and it’s still perfect.  Fast, easy, silent and with a fantastic trimming noise from the front mech as you move across the cassette.

NeilPryde Alize/Nazare with Deda Zero100 stem and Di2 junction box

NeilPryde Alize/Nazare with Deda Zero100 stem and Di2 junction box

One piece of advice/warning I was given was that because of the power of the motors front and rear – NEVER press the gear shift button when you’re not riding as the motors are strong enough to bend the rear mech hanger or bend the front mech. So good practice is to remove the battery whenever you’re not riding it – if someone either accidentally or pushes a shift button or purpose it can do damage to your bike. The same goes for if you’re travelling somewhere in the car – if you go over a bump and your shift lever clicks on a gear – that can be a problem – so disconnect the battery. It’ll save you anguish, potentially cost and keep your gear shifting perfect.

During the setup of the gear shifting speed....

During the setup of the gear shifting speed….

Of course you have to then remember  where you put your battery! I haven’t lost mine yet (nearly but not quite).

NeilPryde Alize (Nazare) Di2 6870 front mech & cranks

NeilPryde Alize (Nazare) Di2 6870 front mech & cranks

Charging the battery took about an hour the first time. Charges should last up to 600km. I took my battery out after about 250km to charge it just in case and it took less than 30minutes to charge. It’s really not something to worry too much about. Obviously the more you change gear, the faster the battery will run down – bot you’ve got hundreds if not thousands of gear shifts per battery charge.

New Ultegra 6870 Di2 rear mech

New Ultegra 6870 Di2 rear mech

Di2 Riding impressions:

In action at the Wiggle UKCE Bournemouth Sportive

In action at the Wiggle UKCE Bournemouth Sportive

Out on the road so far it’s been a joy to use. It’s not pefect – nothing is but it’s very nice indeed. Your are literally just pressing a button to shift. There is some feedback through the button but that’s the bit that’s not quite perfect for me – unless you press the button just enough it doesn’t always shift and I’ve missed a few shifts as a result. If you’re resting your finger on the shift lever hitting a bump can mean you accidentally change gear – but in fairness that’s a problem I have with my Campagnolo Chorus shifters too. Maybe my lever’s are a touch off but if you click more firmly it works perfectly every time.  In the fast shift mode I’m using – the shifts are very quick – and perfect performed. The system trims itself as you move across the cassette meaning all 22 gears are perfectly usable – it also makes a cool noise as it trims which you and your riding companions will audibly hear! The front shift is impressive too and is fine under load – although I always try to lift off a bit shifting up on any bike I ride.

Having the gear shifting working so well also helps my bike run very quietly. Often riding with others when you get to a climb and people start lots of gear shifting to get to the right gear it can be quite noisy as chains clatter across cassettes but there’s none of that with Di2 – no clatter just smooth fast shifting. If you like a quiet bike – Di2 is the best thing I’ve found other than riding a steel bike for a quietness.

So apart from a few tiny niggles around the operation of the shift levers, I’m very, very impressed with Di2. Yes it’s not particularly cheap at roughly the same street price of Dura Ace 9000 mechanical but I suspect it’ll be both cheap to run (due to shifting better and looking after the chain cassette accordingly) and very reliable. This is the 4th generation of Shimano Di2 now, so it should be as reliable as any other high quality Japanese engineering!

It feels like a bit of an extravagance compared to say mechanical Ultegra 6800 which is really good too – but sometimes it’s nice to be able to have a treat and this one certainly is very cool as well as working beautifully. There are more bikes out there now with Di2, so it’s not perhaps the novelty it was say 12 months ago – but Di2 bikes still aren’t exactly everywhere.

Ultegra 6870 Di2 completed install

Ultegra 6870 Di2 completed install

My plan is for this to be a long term test, so I’ll keep riding it though the year and report in on any further findings.  If you have any questions, please let me know. Thanks for reading.

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  • aradilon

    “NEVER press the gear shift button when you’re not riding as the motors are strong enough to bend the rear mech hanger or bend the front mech.” I don’t get why it would bend? And couldn’t u just plug out the cables out of the junction box? Just some questions because i’ve ordered a bike with DI2.

    • girodilento

      Hi Aradilon, thanks for the question. On a mechanical gruppo when you press the shift lever, nothing moves till you pedal. With Di2, pressing the shifter moves the motor instantly, so if you’re not pedalling it will just bend your mech or you gear hanger. It’s instant. So my advice is only press the buttons when your pedalling. Your are right – unplugging the middle lead of the junction box is a good idea for putting you bike in the car. It disconnects the levers, so the buttons can’t be used. It’s what I do. Enjoy your new bike – I love Di2 – it’s fantastic!