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Shimano Ultegra R8170 Di2 Disc Groupset



Fast shifting and brilliant brakes, now on a level with Dura-Ace – but cheaper
Shift quality is amazing
Extra brake pad clearance really helps
App integration
Slight price increase
2,710g Recommends

This product has been selected to feature in recommends. That means it's not just scored well, but we think it stands out as special. Go to recommends

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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The new Shimano Ultegra R8170 Di2 Disc groupset really closes the gap to Dura-Ace. Unless you particularly want to spend more, or need to save that little bit of weight, there is no point in looking past Ultegra R8170. The shifting is smoother across the cassette than previously, and the brakes have improved too. It is just brilliant.

Over the years, Shimano's second-tier groupset has been providing the majority of the performance of the top-tier Dura-Ace groupset, but at a significantly reduced price. That's thanks to less expensive materials, at the cost of a few hundred grams extra weight.

But with the latest R8170 groupset, Shimano has closed the performance gap to the point of undetectability. There is no discernible difference between Ultegra and Dura-Ace. So, unless you particularly want to dip your hand deeper into your pocket, or you need to save a tiny bit of weight, there is absolutely no sensible reason to buy Dura-Ace – Ultegra R8170 is just as good.

The new groupset rides largely like the old one. If you buy it on a complete bike you won't notice the lack of wiring between the shifters and the seatpost-mounted battery, but if you're upgrading it will save a few seconds of wiring.

The lack of wires has absolutely no negative effect on ride feel, and that should be heartily applauded. Shimano has absolutely smashed it out of the park when it comes to shift quality. Where SRAM's eTap has always felt clunky – too clunky, in my opinion, for such a high-end groupset – Shimano's latest Di2 feels smoother and faster than before. And let's be honest, Shimano is improving on shifting quality that was already absolutely fantastic, so to feel an improvement is very impressive.

Shimano Ultegra R8120 Groupset-16


When it comes to braking I can again see improvements. Shimano has fixed the major issue with the R8000 brakes, so now, after you've thoroughly heated up the brakes with a long period of heavy braking, you can let them off and suffer no noise whatsoever. It is a blissful silence that I'm pleased to say has stuck around for the entire test period.

At this level it's worth making sure everything is right, though; prior to having the groupset installed, I had my brake mount surfaces faced, and I can't stress enough how crucial this is. While the front was fine on my frameset, the rear had one surface a whole 0.9mm lower than the other. That might sound tiny, but it is more than enough to cause headaches as you try to set up your brakes.

Shimano Ultegra R8120 Groupset-15

The new brakes also have the progressive feel you'll find on Shimano's GRX gravel groupset. The lever/pad relationship is not linear; you get lots of pad travel at first (to bring them in from a decent clearance) and then far less as you pull harder on the brakes (for easy, smooth modulation). The feel in the hands is lovely, with plenty of control for scrubbing speed into corners and loads of power if you need to stop quickly.

Shimano Ultegra R8120 Groupset-21

I really like the feel of the new levers, too, and the hood shape is very comfortable. The inward tilt of the shifter body feels very natural, and the smooth lines at the front of the levers are great for all-day comfort.

Design changes

Two things have happened here that have really improved performance. First, you'll find 10 per cent extra clearance at the pads. And second, the ServoWave design improves the progression of power through the lever stroke. These two measures have worked brilliantly, creating brakes that are powerful, easy to control and quiet.

Take the pads out and you find what appear to be different pistons. If they stick less over the longterm I'll be happy, but frustratingly Shimano has made them black, so it's hard to see brake dust when you're cleaning them.

Shimano Ultegra R8120 Groupset-14

For the once-per-year occasion when you need to bleed the brakes, the bleed port has been moved to the side of the calliper, allowing much easier access in tight rear triangles. You won't need a spanner any more either, as the port now uses a hex key. It is a much cleaner design, though I have already lost one of the bleed port covers.

And finally, rejoice! The only flathead screw (it held the pads in) has been changed to an Allen bolt. That should reduce the number that need to be drilled out, but you should still use an anti-seize compound just to be safe.


In terms of groupsets, there are few parts that leave an impression like shifters. This is where your hands are going to rest for the majority of a ride. You'll be in contact with them every time you change gear or brake, and if they feel bad it can be incredibly annoying.

Shimano's Ultegra R8170 shifters have (like Dura-Ace) become longer, taller and fatter. Shimano says it's due feedback from the pros, but I suspect that these needing a CR1632 coin cell battery in each shifter also played a role in the increase.

Shimano Ultegra R8120 Groupset-20

With my medium-sized hands I found the new shifters very comfortable, with a secure grip on bumpy roads. Shimano has increased the length of the shifter body to enable you to loop three fingers under the shifter easily.

The button profiles have been altered and are now very pronounced. I have to say I had very few issues with the old levers while wearing gloves anyway, but with the new levers the situation is even better. Up at the top of the shifters you find some extra buttons. I have mine set so the right side starts a new lap with a double press, and single presses change my Garmin screen. It's all very easy to use.

As with the old model, there is plenty of free-stroke and position adjustment so that you can physically tune the levers to your hands.

Rear derailleur

Where you used to have a choice between an SS (short) cage and a GS (medium) cage derailleur, you've now just got the GS option. Shimano has evidently seen that most people (even the pros) use wide-range road cassettes these days, and has sensibly reduced the number of parts it needs to produce.

Shimano Ultegra R8120 Groupset-24

But you probably don't care about Shimano's production lines, so let's talk about how smooth this new derailleur is. This, rather than the speed or power, is the noticeable thing with the R8170 rear derailleur. Shift under full power while you're cross-chaining in the big ring and trying to chase an attack on a climb, and it simply pops you into the gear you've asked for. It does this quickly and quietly.

Shimano Ultegra R8120 Groupset-23

The functionality of the old Junction A box has moved to within the rear derailleur too, and while this is great for integration, I have a few reservations about making the most exposed part of the groupset even more complicated – and therefore even more expensive to replace in the event of a heavy crash.

It also means that on-the-fly gear adjustments are out of the question. It's a minor thing, though, when the improved integration brings out-of-the-box connectivity to Shimano's eTube app.

The internals

Internally you'll find the same motors and hardware as the more expensive Dura-Ace, with the cost and weight differences coming from the less fancy materials for the outer casing.

The motors are now stronger, too, which goes a long way to providing the claimed shift speed increase. Finally, there is a new charging cable which clips easily onto the port.

Front derailleur

The story is similar when you move to the front derailleur. Shimano made noises about an increase in the speed of the shift but, quite honestly, I believe the differences I can feel are due to the derailleur becoming more powerful. It really shoves the chain between rings now, which – provided your indexing and limits are set correctly – results in lightning-quick shifts, even under load.

Shimano Ultegra R8120 Groupset-19

The limit screws have now entirely disappeared from the front derailleur. You're left with just a single support screw, with the method for indexing the gears now also being used to set the derailleur limits. It is a bit more of a faff to set the limits now because you have to keep entering and exiting adjustment mode, but at least there are no tiny limit screws to round off.


The cassette is 12-speed and only available in two options; 11-30t and 11-34t. Combining the former with 52/36t chainrings has given me a gear for pretty much every situation. Shifts are smooth across the whole cassette, and the new 12th sprocket occupies the 16t space. That's ideal for faster flat rides, and I've even found it useful for those faster climbs when you're in the little ring but quite a way down the block. It just evens out cadence changes, which is never a bad thing.

What I really like are the single-tooth jumps for the first seven sprockets of the 11-30t cassette, as the result is the feeling you have the perfect gear at all times on the flat.

> Which chainset is right for you? Should you choose a standard, a compact or something else?

And before we leave the cassette, it is time for everyone to say thank you to Shimano. Yes, this uses a new spline pattern, but it's backwards-compatible with 11-speed Shimano freehubs. You won't have to go out and buy a new wheelset to upgrade to R8170.

Incidentally, we also have the Ultegra C50 wheels on test, but they will be reviewed separately.


Another noticeable change comes at the chainset, which gets a much more symmetrical crank design. While it is a small change to the aesthetics (now much chunkier than before) the real benefit will be felt by third-party power meter brands such as 4iiii and Stages. The increased symmetry in the drive-side crank should make getting balanced and accurate data a bit easier.

Shimano Ultegra R8120 Groupset-22

We're yet to get our hands on the Ultegra R8100-P power meter, but will have an in-depth review when we do.

You might have seen a few reports of Shimano HollowTech II cranks failing, with the bond between the two parts of the drive-side crank usually being the issue. It seems that water was causing corrosion in the bond, possibly after entering via the hollow axle. It's something Shimano says it has addressed with the new cranks, placing a plastic plug inside the axle to keep water out.

> Get your gears shifting sweetly: How to tune a rear derailleur

While it will take several thousand miles to determine the success of these changes, what I can comment on is the shifting performance. The chain moves between the 36t and 52t chainrings incredibly efficiently, and with very little noise. Shimano's chainrings have offered excellent shifting for years, and they continue to do so.

Shimano Ultegra R8120 Groupset-19

One thing I'm sad to see go, though, is the racer's chainring combination of 53/39t. The 52/36t combo is now the largest available with Ultegra; if you want the 54/40t that has replaced the 53/39t, you'll have to step up to Dura-Ace.

You still get the option of 165mm, 170mm, 172.5mm or 175mm crank lengths.


Here Shimano has switched to its 12-speed mountain bike chains. This is the XT chain, which is claimed to be a bit quieter than before thanks to chamfered edges, though in my experience drivetrain noise mostly comes down to the chain lube you use anyway.

The app

As I've mentioned, you've now got Bluetooth connectivity built into the groupset, rather than having to buy the separate D-Fly unit for a silly amount of money.

The app is easy to use and connected me to my gears in minutes. From here you can associate the groupset with a specific bike – useful if you're going to be connecting several other bikes – and make all sorts of useful tweaks. You can switch between shift modes from classic manual to having the front derailleur handled for you, for instance, mess around with which shift button does what, or alter the shifting speed.


The price for the Ultegra R8170 groupset is a little tricky to pin down, but we believe the RRP is £2,399; up from £1,999 for the R8070. That isn't too horrific an increase, and given the improvements across the groupset, I'd be happy to spend my money on it.


I think Shimano has produced a fabulous Ultegra groupset that delivers perfect performance. Now, more than ever before, there really is no point in the vast majority of us paying more for Dura-Ace.


Fast shifting and brilliant brakes, now on a level with Dura-Ace – but cheaper test report

Make and model: Shimano Ultegra R8170 Di2 Disc Groupset

Size tested: 52/36 - 11-30 - 170mm

Tell us what the product is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

From Shimano:

"It's time - to find out what really matters.

The freedom of the open road, crisp mornings and fiery sunsets. Laughter filling the air and then trailing off.

Nature, unfolding as you roll. Breathtaking vistas that stop you in your tracks.

Coffee stops and camaraderie. Route prep and weather checks.

Rain breaks and sunny bursts. Mad dashes. Racing each other to the top. And then kicking back... It's about time – and it's about leaving time behind.

Tuning into tranquillity. And shifting into oneness."

I'm still trying to work out if this feels like shifting into oneness or not.

Tell us some more about the technical aspects of the product?


SHIMANO ULTEGRA Di2 Rear derailleur SHIMANO SHADOW RD 2x12-speed

SHIMANO ULTEGRA Di2 Front Derailleur 2x12-speed

SHIMANO ULTEGRA HOLLOWTECH II Crankset 2x12-speed - 52/36T

SHIMANO ULTEGRA 12-speed HYPERGLIDE+ Road Cassette Sprocket - 11-30T


SHIMANO ULTEGRA Hydraulic Disc Brake Caliper

SHIMANO Built-In Type Di2 Battery [SD300 Type]

Electric Wire SD300 for Internal Routing

Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:
Rate the product for weight (if applicable)
Rate the product for comfort (if applicable)
Rate the product for value:

Tell us how the product performed overall when used for its designed purpose

It's absolutely perfect. Slick, quiet shifting with loads of braking power that is easy to control.

Tell us what you particularly liked about the product

While most people will be singing the praises of the semi-wireless shift quality – quite rightly too – my particular highlight comes at the brakes. The feel of the lever is excellent, and they are quiet when you come off the power too.

Tell us what you particularly disliked about the product

Moving the brains of the system into the rear derailleur is clever, but if you wreck it in a crash, your day just got even more expensive.

How does the price compare to that of similar products in the market, including ones recently tested on

SRAM Force eTap AXS HRD is the main rival and it is cheaper, coming in at around £1,689, though it isn't usually sold as a full groupset.

Did you enjoy using the product? Yes

Would you consider buying the product? Yes

Would you recommend the product to a friend? Yes

Use this box to explain your overall score

The shifting and braking has improved, while Shimano has made the system semi-wireless and moved the Bluetooth and Junction A functions into the rear derailleur. It is absolutely identical in terms of performance to Dura-Ace and, in my opinion, easily beats SRAM's wireless groupsets.

Overall rating: 10/10

About the tester

Age: 27  Height: 177cm  Weight: 62kg

I usually ride: Specialized S-Works Tarmac SL7  My best bike is:

I've been riding for: Under 5 years  I ride: Most days  I would class myself as: Expert

I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, club rides, general fitness riding, I specialise in the Cafe Ride!

Add new comment


bobbypuk | 1 year ago
1 like

Has duar ace got a lot worse worse recently?

I've got a bike with DA 9070 di2 and the latest R8170. Old DA is silent in changing, levers are light touch and shifting is instant. In contrast on the R8170 it feels like an effort to move the shifter and then a big clunk as the chain shifts. With DA people riding beside me would not hear a gear change, no danger of that with the new groupset. I've always found long cage mechs to be slower, louder so maybe thats the reason.

Having said that I do like the little beep when you run out of gears...


Pedal those squares | 1 year ago

Personaly I have gone for a bit of a halfway house...I have Ultegra.  But as bits are worn out I buy Drua Ace....e.g. Chain, Cassette, Disc rota, pads ... minor "gains", but you avoid the main cost of Drua-Ace.

PRSboy | 1 year ago

Well I won't be a buyer when the time comes to replace my ageing 6800 because guess what, rim brakes.

Whilst I appreciate discs are the way forward and all that, it seems a bit short-sighted to exclude those of us who are otherwise perfectly happy with our old steeds but fancy an upgraded groupset.  Presumably tooling of new hoods renders it uneconomic.


Bye bye Shimano...

Secret_squirrel replied to PRSboy | 1 year ago
1 like

AXS isnt available in rim brake afaik - so its Campy all the way I guess.

Rich_cb replied to Secret_squirrel | 1 year ago
1 like

AXS is available in rim brake.

Rendel Harris replied to PRSboy | 1 year ago
1 like

Ultegra 8150 Di2 with rim brakes is still widely available and, if it follows the usual pattern, will still be obtainable from somewhere for a couple of years after it's officially discontinued. 

check12 | 1 year ago

£2000 to £2400 is a 20% increase, pretty big I'd say.

are you going to be returning the frame with the - "While the front was fine on my frameset, the rear had one surface a whole 0.9mm lower than the other." Or do you not mind it left the factory like that  3 

ktache | 1 year ago
1 like

Will never be buying, xc utility commuting mountain biker me, and gone down the rohloff route, but what stands out to me is the removal of the flathead bolt for pad retention!

Imagine a picture of a happy squirrel.

HiFi | 2 years ago
1 like

Isn't 2,710g groupset weight kinda heavy?

matthewn5 replied to HiFi | 2 years ago
HiFi wrote:

Isn't 2,710g groupset weight kinda heavy?

Compared to 2,040g for a 2014 Chorus groupset or 1,840g for a 2014 Super Record, yes, a bit porky perhaps?

AlsoSomniloquism replied to matthewn5 | 2 years ago
1 like

Although not direct comparisons are they? 2022 12 Speed, Disc, Electronic compared to 11 speed, rim and mechanical. The current Disc Super Record EPS is 2,500g. 

HiFi replied to AlsoSomniloquism | 1 year ago
1 like

If you could bring back a SR rider from 2014, and tell him/her they'd be expected to get excited about an ultegra groupset that does the same things but nearly 1Kg heavier (1kg !!!) they'd laugh. Wait, 2014 is only 8 years ago, I can remember 2014, maybe that's why I'm laughing..

IanEdward replied to HiFi | 1 year ago
1 like

Welcome to 2022, heavy is the new lightweight 😎

Saracen888 | 2 years ago

It's a great groupset and worthy of a positive review.

It'd be no suprise that the negative comments come from people who either haven't tried it or can't afford it.

Rendel Harris replied to Saracen888 | 2 years ago
Saracen888 wrote:

It'd be no suprise that the negative comments come from people who either haven't tried it or can't afford it.

I believe that's the same argument used by SUV drivers, people are only agin them because they can't afford them themselves. It's rather vulgar and nouveau riche to assume that anybody disagreeing with you is only doing so because they haven't got your wealth.

srchar | 2 years ago
Liam Cahill wrote:

SRAM's eTap has always felt clunky, too clunky, in my opinion...

Liam Cahill wrote:

...the reason that we have given the SRAM Force eTap AXS Wide groupset our Editor's Choice award is simple: it works brilliantly. The shifting is great... it's up there with the best drivetrains on the market.



ejocs replied to srchar | 2 years ago
Liam Cahill wrote:

The main thing I wanted to see from the new [Shimano] groupset was a set of brakes that worked perfectly. We haven't got that here and I think the rotors are at fault. Yes, the pad clearance has been increased by 10 per cent but that is 10 per cent of a tiny gap. It isn't enough to clear a rotor warped by heat...

This rotor warping results in that annoying ting-ting-ting sound when you come off the brakes after scrubbing off a lot of speed. You can also get a tiny bit of noise if you lean the bike over excessively when sprinting or out of the saddle on a climb.

Liam Cahill wrote:

Two things have happened here that have really improved performance. First, you'll find 10 per cent extra clearance at the pads. And second, the ServoWave design improves the progression of power through the lever stroke. These two measures have worked brilliantly, creating brakes that are powerful, easy to control and quiet... [A]fter you've thoroughly heated up the brakes with a long period of heavy braking, you can let them off and suffer no noise whatsoever. It is a blissful silence that I'm pleased to say has stuck around for the entire test period.

Yes, two different (though closely related) groupsets, and perhaps the Ultegra rotors are genuinely less prone to warping (which would be strange, however, as the pros wouldn't be too pleased with that), but quite contradictory claims nonetheless and no effort made to resolve or even acknowledge the contradiction.

(edit: I want to clarify that I'm not having a go at Liam; he's hardly the only cycling journalist producing questionable material. I want to know where the editors are. And when someone is going to acknowledge what an absolute shit show cycling reviews are and actually do something about it.)

chrisonabike replied to ejocs | 2 years ago

I think if you're a journo needing to be reminded of the opinions you formerly put down is a regular thing.  There may be some "conspiracy" in this (e.g. "you need to write about this new stuff by our sponsor which is really great, m'kay?").  However we all confidently opinionate on a dozen things a day, most which are tangential to our longer-term interests and beliefs.  Only journos (and now users of social media) get confronted with the contradictions however.

Heck - even Bob Dylan was apparently an enthusiastic user of "Complete Bob Dylan" songbooks.  You forget...

Sriracha replied to chrisonabike | 2 years ago

Given that so much of a review is either subjective feel or statistically insignificant, I doubt there would be much repeatability of results anyway, if the tests were to be done double-blind.

Liam Cahill replied to chrisonabike | 2 years ago

Hi chrisonatrike. All of our sponsored content is clearly marked and no review can ever be sponsored. No "conspiracy" here, I'm afraid.

chrisonabike replied to Liam Cahill | 2 years ago
1 like

Good to know.  I'll be watching out for any more of those L-shaped crank adverts though although I've not yet worked out who's paying you for those...

Liam Cahill replied to ejocs | 2 years ago

Hi ejocs. Apologies for not addressing the contradiction in the main body of the review. I'll clarify here by saying that, as with the previous generation of each groupset, the lower-end rotors seem to be better for avoiding warping than the Dura-Ace/XTR model.

I don't know why. It could be that DA is too focused on weight, but I've consistently had better running performance from lower-end rotors, or those that simply have more material, such as SwissStop's Catalyst rotor.

Liam Cahill replied to srchar | 2 years ago

Hi srchar. Top one is my opinion, the second one comes from an article that I wrote rounding up many of the component reviews at the end of 2020. The words, therefore, are not mine. 

lio | 2 years ago
1 like

I don't see any mention of it but has Ultegra lost its clutch mech option?

The long cage RX mech was great. 

Secret_squirrel replied to lio | 2 years ago

Think Shimano want you to buy the GRX mechs for CX now. 

wtjs | 2 years ago
1 like

I had my brake mount surfaces faced, and I can't stress enough how crucial this is. While the front was fine on my frameset, the rear had one surface a whole 0.9mm lower than the other. That might sound tiny, but it is more than enough to cause headaches as you try to set up your brakes

Seems like very important information. Looks like those of us with cable discs have it easy!

Secret_squirrel replied to wtjs | 2 years ago
1 like

Facing should always be done. Regardless of disc brake type. 

IanMSpencer replied to Secret_squirrel | 2 years ago

These days most bikes are bought pre-built so you would expect the manufacturer to do the facing, unlike the days of buying a frame.

So what is being highlighted is poor quality control and reworking by re-facing. A good bike shop might pick up the issue on the PDI.

As SS says, brake type is irrelevant, and there are other areas on the bike that might need facing, but with presshfit bearings and integrated headsets, the remaining opportunities to fix build problems is reduced.

Stuff like this is why cheap BSOs from Halfords are best avoided because often the frames don't line up and no amount of fettling can get stuff to work.

Joe Totale | 2 years ago

Or £1,300 more expensive than an Ultegra R8020 groupset because Shimano are forcing us towards Di2 if you want a high end groupset.

Prosper0 | 2 years ago

£2400 up from £2000 is a 20% price increase on the previous version. That's not a small thing, that's insane. 


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