Shimano Ultegra R8070 Di2 Disc Groupset Review

For 2018, Shimano has upped the ante with their latest Ultegra R8070 groupset by making it identical to Dura-Ace in form, function and design. You heard me, identical. What’s not identical is the material used (alloy instead of titanium and carbon). At the end fo the day, you’ll have to decide if Ultegra or Dura-Ace is your jam, but I’m here to say that my vote and my money would be for the latest Shimano Ultegra R8070 Di2.

Shimano Ultegra R8070 Di2 Disc Groupset Features:

• Updated top-to-bottom to be identical to latest Dura-Ace in form and function
• New hood design is smaller and more configurable
• 10mm lever reach adjustment
• Shift buttons only require 2mm movement
• Same ergonomics and shifting as Dura-Ace Di2
• Compatible with Shimano E-Tube apps for configuration
• FC-R8000 Hollowtech II crankset
• Compatible with up to 11-34t cassette
• MSRP: ~$1800 (depending on configuration)

Ultegra Di2 is all you really need

The latest electronic groupsets are getting better and better. While SRAM eTap continues to gain followers, there’s no question that the king of road groupsets is Shimano’s workhorse Ultegra kit. And, with the 2018 model year, Shimano updated Ultegra to have the exact same form-factor and function as Dura-Ace, but without all the expensive materials.

So, what that means is if you really do want the lightest Di2 groupset possible, then by all means, go Dura-Ace. But, if you want the exact same performance at a lower cost then Ultegra R8070 Di2 should be your choice.

Having ridden Di2 many times in past years, this was my first time doing a complete build from wheels-up. Built up aboard the Factor O2 Disc, the full-tilt R8070 disc groupset has been reliable, consistent and smooth overall with only a couple of small gotchas.

When building up a complete Di2 bike, be prepared to purchase a ton of parts. You see, there’s no full bike kit available as Shimano relies on you (or your mechanic) to know all the proper pieces you’ll need. That includes appropriate wire lengths, individual brake calipers, junction boxes and more. In all, it’s a daunting box of jumbled parts that can only be assembled by someone with solid skills. I trusted Adrian at The Bike Shed here in Sandy, Utah to build this one up. He took his time, but spent several hours to make it just right. That TLC paid off with one small hiccup (another cliffhanger).

Dramatic improvements to ergonomics

After having used prior-generation Shimano Di2 and mechanical disc groupsets, the R8070 was an absolute delight. The hood shape is much smaller and is more comfortable in-hand. You can comfortably wrap your hands around the hoods to sprint or just motor along. Rolling deep in the hoods for miles, everything just feels natural and the hood shape is diminutive compared to SRAM’s eTap. On top of that, there are configurable buttons atop the hoods that can be used for shifting or accessory controls.

Shifting function is standard Di2 fare with two buttons and fixed brake levers. That last point is worth mentioning as Shimano’s mechanical groupsets feature lever-based Dual Control, which is not one of my favorite things. I much prefer brake levers that do one thing — brake. Because of that the levers are more ergonomic and better-suited for braking, with a great in-hand feel in the drops or hoods. These are definitely Shimano’s best levers yet and they feature reach adjustments for an even more personalized fit.

The shape of the shift buttons are improved over the previous-generation, but they are still not as good as eTap when wearing full-finger gloves. Again, Shimano asserts that the buttons are optimized for racing and performance, which rarely happens in weather requiring full-finger gloves. To help during winter months, the buttons on top of the hoods should be programmed to shift the rear derailleur.

Many framesets feature integrated Di2 junction boxes and battery mounts inside the downtube (like he Pinarello Dogma F10), but the Factor O2 Disc used for testing does not. As such, I hung a standard junction box underneath the Black Inc Barstem for an functional, but less-sexy look. For bikes without Di2 integration, the preferred method should be the new handlebar end plug junction box, but not all bars are compatible. If you go that route, just make sure your bars are Di2-compatible (like the PRO Vibe Carbon).

Reliable, smooth shifting

Many people swear that Di2 is the smoothest shifting available. I will confirm that it is indeed smooth and responsive when shifting both front and rear derailleur. The chain moves with precision both up and down the cassette and gear dumps (hold down the button) are rapid as well. Click, shift… click, shift — every time. As an aside, all that superb shifting delivers added torque on the derailleur and drivetrain, so be sure to properly torque your derailleur and re-check regularly.  My rear derailleur worked itself loose and caused poor shifting for a ride until I noticed that the bolt had worked itself loose. A quick fix and shifting perfection returned.

Again, all ramp angles and shifting on Ultegra R8070 is identical to those of Dura-Ace R9070. As such, the cassette always obliged with every touch of the shifter under load or not.

To protect cross chain, Di2 prevents you from using the two smallest gears with your small chainring — effectively turning it into a 20-speed drivetrain. Granted, you should never ride in that gearing and Di2 just ensures it.

One of the most impressive features of Ultegra R8070 is the auto-trimming front derailleur. To make front shifting as quick and precise as possible, there’s little clearance between the cage and chain. When shifting chainrings, some gear combinations result in chain rasp. All it takes is about 10 pedal strokes and zzzzzzp, it trims itself out — pretty neat.

Consistent, powerful braking

Disc brakes offer superb braking in all conditions — even luddites can’t refute that. Are they necessary for dry conditions or all riders? No, they aren’t. But, it’s where the industry is heading and riders using them will rarely wish to go back to rim brakes.

I’ve stuck with 160mm rotors front and rear on all my road bikes, which is what the industry recommends. However, professionals and cyclocross riders are making do with 140mm rotors. Even though they may seem large on svelte road bikes, I’m sticking with 160mm for increased power and improved cooling.

In that regard, I’ve experienced excellent brake feel and modulation with the R8070 disc brakes. However, the rear brake has been a bit finicky to bleed properly. During the course of testing, I had to re-bleed the system twice. After that second time, I’ve had no problems and the contact point remained consistent.

Tweaking Di2 has its challenges

Another renowned feature of Di2 is its configurability. All configuration must be performed using Shimano’s Windows-based E-Tube app, unless you install the Di2 Inline Wireless Unit (which I did). Installing and using the Windows app isn’t for the faint-of-heart. I’m pretty technical, but the Japanese-translated interfaces are lacking in modern usability in a big way. And, it is Windows only.

But what about the E-Tube mobile app? Well, that had catastrophic results for me. I was able to connect to the system on my iPhone and it immediately began a firmware update (sans approval) and, within a few seconds, failed. That half-completed firmware updated completely bricked the system. #%@!%? Yeah, I had a useless drivetrain until I could source a Windows laptop from a neighbor and revive the system by re-installing the firmware from ground zero. Sadly, after that experience, I’ve been hesitant to use the mobile app and haven’t retried. Can you blame me?

I have, however, ridden Shimano Dura-Ace R9000 with both Sprint Shifters and hood buttons configured to shift eTap-style with the left button going up the cassette and right button going down. With Sprint Shifters, you can get the best of both worlds and shift with ease in the drops.

Because I didn’t have the guts to re-use the E-Tube mobile app, I wasn’t able to test Synchronized Shift where the drivetrain automatically shifts the front derailleur for you. I’ll post updates if I can get it to work. But, your LBS may be your best bet to get the most out of your new Di2 setup.

The Good

• Responsive shifting under all conditions
• Same performance as Dura-Ace at a fraction of the price
• Can integrate with head units and other systems
• Bikes with integrated junction boxes are sleek and beautiful (bar end plug is next best)
• Wonderful ergonomics for shifting, braking and sprinting
• Adding Sprint Shifters makes things even better in the drops
• Configurable system can be tweaked to your liking
• Powerful braking delivers excellent stopping power always (wet/dry)

The Bad

• Windows-only configuration
• Poor experience with E-Tube mobile app (e.g. bricked the system)
• Rear brake required multiple bleeds to get right (likely cable routing issue and has been remedied, finally)
• Traditional under-stem junction box is unsightly

The Bottom Line: Shimano Ultegra R8070 Di2 Disc

The updated Shimano R8070 Di2 groupset is truly a fantastic drivetrain — once you work through or around a few quirks. With an updated, smaller hood design, long days in the hoods are super-comfortable and shifting/braking is second-nature. Going with disc brakes yields powerful, modulated braking in all conditions. Even though Di2 requires running wires everywhere, Ultegra R8070 is the best-priced electronic group that’s equally at home on a custom build (like the Factor O2 Disc) or off-the-shelf at your local bike shop. Shifting is fantastic and overall performance is as good as Dura-Ace and other top-end groupsets.

Buy Now: Available at CompetitiveCyclist.com

 

In Summary

9.0 Affordable Perfection

After almost a year of use, Shimano's latest Ultegra R8070 Di2 continues to deliver quality shifting and overall performance. It's also the most affordable electronic groupset on the market, so you can spend that extra coin on a nicer cockpit, wheels or frame. If you live in a Windows world, you'll relish the adjustability, but Mac users will be left wanting.

• Shift Quality 10
• Braking 9
• Ergonomics 9
• Setup and Adjustability 7
• Overall Value 10