12-speed Dura-Ace vs Ultegra vs 105 Di2 and GRX - what are the differences?
There are four 12-speed Di2 groupsets: Dura-Ace R9200, Ultegra R8100, 105 R7150, and GRX RX825. They’re all 2x12 groups, so what are the differences, really?
Shimano groupset ranking
First, since you may or may not be familiar with Shimano groupset names, I’ll quickly explain the Dura-Ace, Ultegra, and 105 names.
Shimano’s Dura-Ace groupset is the top tier Shimano groupset. It is the best and lightest that money can buy. This is what professional cyclists ride.
Ultegra sits one level below Dura-Ace. It’s less expensive and weighs more. On the other hand, performance is pretty much identical to Dura-Ace.
105 has always been the groupset of the people. Its performance is very close to that of Ultegra. This is the cheapest 12-speed Di2 road groupset you can buy.
The remaining groupset, GRX, is Shimano's Gravel groupset. 12-speed GRX is based on 105 Di2, but with subtle tweaks that improve the gravel experience.
GRX shifters are shaped slightly different, the rear derailleur has a clutch to maintain chain tension, and the front derailleur allows for more tyre clearance.
Dura-Ace vs Ultegra vs 105 weight and price comparison
Wondering what the weight difference is? Here are all of the component weights, according to Shimano’s own pages.
Note that the total weights do not take into account wires and junctions. Rim brake groupsets generally require 4-5 wires and a junction, while disc brake systems use just two wires.
The total weight for a rim brake Dura-Ace R9200 groupset is 1859g, while the more common disc brake groupset weighs 2058g.
Individual component parts are as follows:
- Rear derailleur RD-R9250: 215g
- Front derailleur FD-R9250: 96g
- Cassette (11-34T): 253g
- Crankset 50-34T 170mm: 685g
- Disc brake shifter ST-R9270: 350g (pair)
- Disc brake caliper BR-R9270: 194g (pair)
- Disc rotor: 212g (pair)
- Rim brake shifter ST-R9250: 230g (pair)
- Rim brake caliper BR-R9200: 327g (pair)
- Battery BT-DN300: 53g
- EW-SD300 wire: 12.5g (per wire)
- EW-JC304 4-port junction: 5g
Ultegra
Ultegra R8200 disc brake total weight is 2349. The rim brake version weighs 2133g.
- Rear derailleur RD-R8150: 262g
- Front derailleur FD-R8150: 116g
- Cassette (11-34T): 345g
- Crankset 50-34T 170mm: 700g
- Disc brake shifter ST-R8170: 391g (pair)
- Disc brake caliper BR-R8170: 246g (pair)
- Disc rotor: 236g (pair)
- Rim brake shifter ST-R8150: 295g (pair)
- Rim brake caliper BR-R8100: 362g (pair)
- Battery BT-DN300: 53g
- EW-SD300 wire: 12.5g (per wire)
- EW-JC304 4-port junction: 5g
105
The 105 disc brake only R7150 groupset weighs 2562g, including wires.
- Rear derailleur RD-R7150: 302g
- Front derailleur FD-R7150: 142g
- Cassette (11-34T): 361g
- Crankset 50-34T 170mm: 754g
- Disc brake shifter ST-R7170: 423g (pair)
- Disc brake caliper BR-R7170: 246g (pair)
- Disc rotor: 256g (pair)
- Battery BT-DN300: 53g
- EW-SD300 wires: 25g (pair)
GRX
12-speed GRX is disc brake only, and weighs about 2470g.
- Rear derailleur RD-RX825: 310g
- Front derailleur FD-RX825: 142g
- Cassette: use any of the road cassettes
- Crankset 48-31T 170mm: 710g
- Disc brake shifter ST-RX825: 415g (pair)
- Disc brake caliper BR-RX820: 261g (pair)
- Disc rotor RT-CL800: 97g (140 mm), 114g (160 mm)
- Battery BT-DN300: 53g
- EW-SD300 wires: 25g (pair)
Components on Amazon
Here are my (affiliate link) pages listing all components for these groupsets, with current prices and availability:
Groupset prices
An entire 105 R7150 group costs about $1900, compared to $2400 for R8170 Ultegra/GRX and $3900 for R9270 Dura-Ace. Rim brake versions of Ultegra and Dura-Ace are slightly cheaper: $3600 and $2100, but don’t feature wireless shifting.
Features
Weighs and prices aside, let’s take a look at the real differences between these groups. Generally speaking, the only difference between Dura-Ace and Ultegra is the materials used.
There are simply more lightweight Carbon Fiber Reinforced Plastic (CFRP) parts in Dura-Ace components. The servo motors and circuit boards used in the derailleurs and shifters are exactly the same for Dura-Ace and Ultegra.
105 Di2 parts are a bit less sophisticated, and - in some cases - are essentially older components repackaged.
12-speed GRX is very close to 105 Di2 in terms of performance and aesthetics.
Wireless vs wired - or Disc vs Rim
All four groupsets feature wireless shifting, with the derailleurs connected to the battery via wire. However, it’s only the hydraulic disc brake levers that support wireless shifting. If you’re on rim brakes, your only choice is wired shifting.
GRX ST-RX825, Ultegra ST-R8170 and Dura-Ace ST-R9270 hydraulic disc shift levers can be wired to the battery, increasing the main battery life (time between charges) by about 50%. Wiring up the shift levers also eliminates the "wake up" shift that occurs on all wireless Di2 systems.
105 Di2 only supports wireless shifting, and disc brakes only. You can not wire 105 Di2 systems to the rest of the system (unless for firmware updates), and there are no 105 Di2 rim brake shifters.
Regardless of whether or not you’re using wireless shifting, all 12-speed Di2 road groupsets feature wireless BluetoothLE/ANT communications through the rear derailleur.
Shift levers
Apart from the weight and looks, the Dura-Ace and Ultegra shift levers are the same. They both have two shift buttons, and a hidden hood button. Also, they have one (disc brake levers) or two (rim brake levers) SD300 E-Tube ports and one satellite shifter port.
On the other hand, 105 Di2 shifters do not have hood buttons, and the SD300 port they have can only be used to run diagnostics and update firmware. You cannot connect TT shifters to 105 Di2 shift levers, and satellite shifters won’t work either.
The wireless Dura-Ace and Ultegra disc brake shifters operate on one CR1632 battery, which should be good for 1-2 years of use. 105 Di2 shifters have two CR1632 batteries, and they’ll last about 3-4 years.
All 12-speed hydraulic disc levers let you tweak the free stroke and reach, and Ultegra and Dura-Ace levers also feature servo wave (105 does not).
Rear derailleurs
Each 12-speed Di2 road rear derailleur is also the system’s main junction. Twelve-speed road derailleurs have a charge port, a button, a LED, and two 11-tooth pulleys. The differences are in the materials used (weight), supported cassettes, and gearing.
The 105 RD-R7150 supports cassettes up to 36T, while the Dura-Ace RD-R9250 and Ultegra RD-R8150 max sprocket size is 34T. The total capacity is similar too: 37T for Dura-Ace RD-R9250, 39T for the Ultegra RD-R8150, and 41T for 105 RD-R7150.
Front derailleurs
I’m repeating myself here, but that’s just the way it is: the Dura-Ace (FD-R9250) and Ultegra (FD-R8150) are functionally identical. The only difference here is in the price, weight, and looks. According to the specs, the Dura-Ace front derailleur goes up to 54T chain rings while the Ultegra one accepts up to 52T. I’d wager that you can use 54T with Ultegra just fine though - it’s just that Shimano don’t make 12-speed 54T Ultegra chain rings.
Unlike its more expensive siblings, the 105 FD-R7150 is essentially last generation’s 11-speed front derailleur with new firmware and a 105 logo slapped onto it. This derailleur is very similar to the 11-speed Ultegra FD-R8050 and the 11-speed GRX FD-RX815 - it even sounds the same.
It's not sleek and aerodynamic like the other 12-speed front derailleurs, but whether or not that really matters is up to you. This front derailleur design has worked fine for many years now, and I don't see that changing any time soon. The 105 front derailleur is marginally slower than the Ultegra and Dura-Ace front derailleurs.
Despite running R8100 Ultegra myself, I also bought the 105 FD-R7150. You see, one more difference between this and all other Di2 front derailleurs is that it has one limits bolt and one electronic limit.
It is unique in a sense and has its very own adjustment guide on the site.
Cranksets
The only difference in cranksets is that Shimano only makes 54T-40T chain rings and 167.5mm and 177.5mm length cranks for Dura-Ace systems. Other than that, all 12-speed road cranksets come in either 52T-36T or 50T-34T, and several crank arm lengths: 160mm, 165mm, 170mm, 172.5mm, 175mm.
You can use Dura-Ace chain rings with 105 cranksets, or 105 chain rings with Ultegra/Dura-Ace cranksets, so there's no problem there. The color and materials will be different, but they’ll work just fine.
One thing that won't work, however, is using 12-speed chain rings on 11-speed cranks. They simply won't fit. For more information on upgrading 11-speed to 12-speed and what does and does not work, see my page on building a 12-speed Di2 bike.
Cassettes
Dura-Ace and Ultegra cassettes come in two versions: 11-30T and 11-34T. There are also two 105-level cassettes: the 11-34T CS-R7101-12, and the non-series 11-36T CS-HG710-12.
You can use the 105-level cassettes with Dura-Ace and Ultegra derailleurs too, shifting might be slightly less smooth than you’re used to. the 105-level cassettes do not have the HyperGlide+ shift ramps
Note that while officially the Ultegra and Dura-Ace derailleurs do not support 36T cassettes, you can probably use a 36T cassette without issue. Shimano limits have always been rather conservative (safe) in the past.
Brakes
There are no 105-level rim brakes, this groupset only supports disc brakes. Dura-Ace and Ultegra come in both disc and rim brake versions.
The 12-speed rim brake calipers are the same as the 11-speed rim brake calipers, even the weights are the same. Shimano has updated the colors to match the rest of the 12-speed groups, but that's it.
Most of the development time went into making disc brakes better, and all 12-speed disc groupsets' calipers feature 10% extra clearance between the disc brake pads and rotors. That should help eliminate rotor rub.
Ultegra and Dura-Ace systems also have Servo-Wave, while 105 does not - the ST-R7170 shifters do not support servo wave.
Synchronized Shift, connectivity, and more
Software-wise, the four 12-speed Di2 groupsets are almost identical. They all feature wireless connectivity over BluetoothLE / ANT, they all support synchronized shift, and you can set up and tweak each of the groupsets using Shimano’s E-Tube Ride app.
The only place they differ is the feature called Gear Position Control. This feature locks out the smallest two sprockets when in the smallest chain ring, and it only exists for Dura-Ace R9200.
Ultegra R8100 and 105 R7100 do not allow you to lock out the smallest two cassette sprockets.
Which should you choose?
In the end, it's up to you. Well, unless you want a rim-brake bike. Or want to use clip-on tt/tri bars. Or want to install satellite shifters. 105 Di2 shift levers do not support any of this.
Fortunately, all 12-speed road di2 groupsets are cross-compatible. You can use any 12-speed road di2 part with any other 12-speed road di2 part, as long as you can plug it in.
Do you want the hidden hood buttons? Or use satellite shifters? Swap those 105 shifters out for the Ultegra ones and you're good to go. The 105 rear derailleur will work with Ultegra or Dura-Ace shifter just fine!
For a quick review of R8100 and whether or not it's really worth it, check out the Shimano Ultegra R8100 review at CyclistsHub.com.
Questions? Comments?
That's it for now - those are all the points worth comparing that I can think of at this time. Of course, please post a comment below or send me a message if you feel something is missing! I'm only human, after all, and love feedback and suggestions. Thanks!
