Cannondale Slice UItegra Di2 – Review

The challenge with reviewing a product that seeks to buck a trend is that all of our standard comparisons fall flat. Of course it’s not that we can’t make a comparison. The issue is that the comparison itself may be unfair. For example, how can we compare a product against previous benchmarks if the product was actually designed to go against them? This was the challenge when we took our first look at the 2015 Cannondale Slice.


The first thing that Cannondale told us about the new Slice was that this was a bike built for balance—ensuring that you could get to T2 as fast as possible without compromising your ability in the run. The key take away being that Cannondale wasn’t going to build a bike that risked your performance on the run. And if that meant they weren’t going to win any wind tunnel shootouts, they were perfectly fine with that. What did that mean to us? Well, for starters, that meant our standard data comparisons were somewhat useless. If a company flat out tells you that aero is not the TOP priority, then you cannot base your opinion on the aero data alone or the lack of aero elements. What you need is actual time with the bike in addition to a long, hard look at the data to see what the term “balance” really means.


We’ve had the Slice for a little over a month now and feel confident that we have a good idea of what Cannondale meant by “balance,” as well as what that really means for you as the rider. But before we jump to our thoughts, let’s take a moment to explore what Cannondale has built.

The 2015 Cannondale Slice

The 2015 Slice was built to balance seven major characteristics that define a triathlon bike – aerodynamics, ease-of-use, handling, fit, comfort, stiffness, and weight. All together, these characteristics have a huge impact not just on our bike splits, but on our run as well. Think of it like this… If you spend 112 miles in an uncomfortable fit to achieve into the ultimate aero position – your body simply isn’t going to be ready to run another 26 miles. Although if you are as comfortable and rested as can be but take more than 8 hours to reach T2, that definitely won’t work either. Cannondale believes that there has to be a happy medium – and built a bike to find it.


The first thing you notice when you walk up to the Slice is just how thin it looks. None of the tube shapes are extraordinarily deep. The Slice was built on the premise that thin is both light and aero. In fact, Cannondale took this school of thought so far that the thinness of the seat stays has compromised the bike’s UCI legality. The result was a bike that undercut its competitors by 300g (computed on a size 54 or equivalent).

Weight graph

Speaking of competitors, it’s important to discuss what this bike is and isn’t. The Slice is not a superbike and, for the most part, it doesn’t pretend to be (the $10,830 Slice Black Inc. non-withstanding). This is a bike designed to compete against bikes in the $2,000-$5,200 market. This makes the P2, P3, Shiv, and B2 some of its main competitors.


In the tunnel, the Slice is going to give up something to its competitors. However, this is something Cannondale is ok with. While they admit that when all things are equal the most aero bike wins out, the only place on Earth where all things are truly equal is in the tunnel. The real world is always going to throw you a curve ball—or three. And of course we have to remember that Heather Jackson has been pretty successful on the original Slice frame, and if you look at the charts below, the new Slice has the old Slice beat.

Slice Drag

Cannondale built the Slice to be easy for the home mechanic to wrench and build. This is an especially welcome feature for those among us who travel with their bike. It’s nice to know that you aren’t going to have to track down a bike shop to rebuild the bike when you reach your destination. The Slice comes with a standard steerer tube and stem (nothing complex there). The front brake is a Shimano direct mount located in front of the fork. Again, this not a super bike. So there’s no surprise there with the lack of integrated fork or brake. The rear brake is also a Shimano direct mount located below the chain stays. At the rear, Cannondale has gone with vertical dropouts. While you lose a bit of fine tuning and adjustability, the upside is faster wheel changes—a “nice-to-have” feature while in the comfort of your garage and major time-saver on course where every extra second counts.


Guru Fit Systems (owned by the same parent company as Cannondale) was a heavy influencer in the design of this bike. The Slice features a 79° seat angle (with an effective range of 77° to 81°). Cannondale moved the fork and wheel forward to allow an athlete to maintain in that angle, while creating a more stable bike. Going with the current trend of shorter cranks, 44-54cm Slices receive 165mm cranks, and the 57-60mm get 170mm.

Riding the Slice

Let’s get the big question that’s probably on all of your minds out of the way now: is the Slice slow? Our answer to that is going to be based partly on our own subjective opinions and partly on the objective data of our Strava segments. And in both of those cases, the answer is flat out no. In fact, we actually set a few Strava PRs over these past weeks with the Slice. Throughout our time with the bike we never felt that the Slice frame was causing us undo slowness as compared to other frames in its class (although more than once we did wish we had a deeper set of wheels than the Vision T30s that ship with the Slice Di2). Don’t get us wrong, we are in no way saying that this is the fastest frame on the market, or even in this price point. And the aero data overwhelmingly supports that fact. We’re saying that we never felt this frame was holding us back. We rode the Slice quite often with another editor on our Shiv test bike (with Reynolds Aero wheels), and the Slice more than held its own. Are there faster bikes out there? Of course. And Cannondale would even agree with that statement. But would we call the Slice slow? Absolutely not.


The frame makes for an extremely comfortable cruiser. We did quite a few half-century rides with the Slice and found ourselves hopping off the bike feeling relaxed and refreshed. What makes this bike non-UCI legal are the ultra-thin NaeroTec seat stays. The seatstays have an extremely thin profile that Cannondale claims to be both extremely aero and ultra-compliant. These, along with the AeroPlane chainstays that are laterally stiff but vertically compliant, make up what Cannondale calls the AERO SAVE micro-suspension and states that the Slice is “more compliant than most endurance road frames.” The end result is a bike that can soak up the miles.

Comfort Graph

One of our concerns was if this amount of claimed comfort would compromise the ability for the Slice to transfer power. Would we be able to sprint when the time called for it? The answer to that question was a definite yes. Thanks to the bike’s light weight, we never had an issue getting it up to speed. In fact, one of our last rides with the Slice was a perfect test of this. We completed a half-century charity ride back in February where the peloton yo-yoed around the turns, forcing us to sprint to get back up front. Never once did we wish for a proper road bike. Instead, we got a little chuckle as we saw roadies clinging on to our wheel to pull them back on.


Speaking of riding in a peloton, the Slice is easily one of the most agile tri bikes we have ever ridden.  Based on Cannondale’s philosophy of balance, this is something we had expected to find, and find we did. This bike found itself comfortably at home in a large peloton or when taking a hard turn. The only negative regarding handling was that the Slice sometimes felt a touch twitchy. The front moves with an amazing adeptness, but when on the aerobars we sometimes found ourselves wishing for something that didn’t want to move around so much. However, to be fair, we think this was partly due to the fact that we were trying to fit ourselves to a demo bike. The lack of an exact fit forced us a little farther out over the aerobars than we’d prefer. Therefore it’s possible that a shorter stem and adjustment to the aerobars could have rectified the issue.


Braking performance on the Slice was excellent. The Ultegra direct mount brakes front and back are excellent, and combined with the alloy Vision T30 wheels, we were able to stop on a dime no matter what the conditions. And of course the fact that this bike is a featherweight probably didn’t hurt braking power either.


The Vision T30 wheels themselves were more than adequate. While not nearly as aero as other options out there, they were a great set of training wheels. They soaked up the road and handled well. These wheels contributed much to the strong handling and braking characteristics of the Slice and feel as though they were intentionally paired with the frame, not just as a pricing decision.


One thing we found missing time and again on the Slice are any sort of additional locations for nutrition or storage besides the standard two water bottle mounts on the frame. We wouldn’t expect the kind of integrated storage found on today’s super bikes, but the lack of even top tube bosses was a real surprise for us. Today we consider these types of features to be standard, not add-ons. Cannondale told us that they wanted to leave all nutrition and storage decisions up to the athlete, but the lack of the top tube bosses really struck us. The good news is that these kind of features are easy to add to future model years, so fingers crossed for 2016.

Slice Ultegra Di2

The Slice is available in five specs – 105, Ultegra, Ultegra Di2, Dura Ace Di2, and Black Inc.—with prices running from $2,710 for the 105 build to $10,830 for the Black Inc. We’ve spent our time with the middle of the lineup, Ultegra Di2 ($5,200), which is available in both a men’s and women’s version (we had the men’s). The Ultegra Di2 version features a full Shimano group set (derailleurs, chain, and cassette) with a Cannondale HollowGram Si crank. The saddle is a Fi’z:ik Arione TriTone, and the Di2 rolls on the aforementioned Vision T30 wheels.


While we appreciate that Cannondale ships with a complete groupset including the consumables (chain and cassette), we did have one major issue with the component selection. The Di2 version ships with a set of alloy brake levers instead of Shimano’s superb Di2 brake levers. To us one of the major selling points of Di2 is the ability to shift from multiple positions. Yet the Slice Ultegra Di2 neglects this part. But the good news is that this is an easy add-on purchase for anyone considering the Slice Ultegra Di2.


The cockpit itself is a Cannondale C3 basebar with Vision TriMax Team carbon clip-on aerobars. A major point to note with the aerobars is the pads lack fore and back adjustability. If you want to bring them in you’ll need to cut the bars. Luckily, if you want to resell, aerobars are cheap. And wiring Di2 pods through an aerobar is a fairly straight forward affair.


The Slice 105

We expect the Slice 105 to be the volume seller of the Slice range. For $2,710 you get Shimano 105 5800 derailleurs, 105 brakes, a FSA Gossamer Pro crank, and microshift bar-end shifters (carbon). Up top you will find a Cannondale Ergo Tri saddle and you’ll be rolling on Shimano RS11 wheels. From a total package perspective, the 105 falls right in line with todays ‘entry-level’ triathlon bikes. Comparably, the Cervelo P2 with Shimano 105 5800 sells for $2,800 and is very similarly spec’d.


Similar to the Ultegra Di2 model, we do have one issue with how Cannondale spec’d the 105. The Slice 105 ships with the same carbon aerobars that are found on the Ultegra Di2 model. While we find these bars to be fine on a $5,200 bike where we assume the rider is fairly stable with their fit and position, an ‘entry-level’ model may need to accommodate a rider who changes their fit multiple times as they grow accustomed to a triathlon position. In that case, we would like to see something much more adjustable. After all, you cannot just glue on the bits of bar you may have cut off previously. We would much rather see a more adjustable aerobar option on a bike at this price point.

Wrapping Up

So how does a bike that doesn’t try to fit the conventional trends fair? Honestly, it impressed us. Here was a successor to the Kona-winning Slice that instead of valuing aero above all else went with a more balanced approach. We really didn’t know what to expect when the Slice showed up, and thus kept our expectations in check. Yet the Slice so far exceeded those expectations that we were shocked. It seemed that almost every time we finished our rides with the Slice there was a look of surprise on our faces. The Slice regularly out-performed what we thought it could do. It is clearly a bike worth taking a look at in this price range. Cannondale calls their balanced approach “Real Tri Technology for Real Triathletes,” saying “it’s a better way to tri.” And after spending time with the Slice, we have to admit that it seems hard to disagree.

[Edit 3/29/2015 – Updated the price range where the Slice best competes]

17 responses to “Cannondale Slice UItegra Di2 – Review

  1. Interesting reading… glad to see that the wheels aren’t completely rubbish either as seems to be the trend at this price point. It Makes the Felt B2 look very good value though… but that’s the wrong colour!

  2. A swing & a miss on Cannondale’s part…
    The old Slice never cracked my top 25 bikes to own…this one fails to crack the top 20…This bike is an improvement, but tremendously underwhelming….Luckily, for those who desire it, it will be found discounted everywhere by mid season. (& plenty of shops will have multiple sets of those Vision bars at giveaway prices, leftover from the 92% of customer who won’t want them)

    • Hi Mick obviously you have not ridden this beast and cant understand the concept behind this bike i bet you are one of those muppets on the specialized band wagon.

  3. I’m guessing the “old Slice” isn’t the Slice RS. I wonder how the aerodynamics of the Slice RS compares to this version of the Slice.

  4. I guess the big question is, which one would you buy at that price point, the Slice or the P2? Is the Slice that much more comfortable than the P2 that you’d choose it for something like Ironman even though it’s not as aerodynamic?

    • Doug our decision would come down first to fit and feel. We would want to spend time on each at our local bike shop and see on which one we think we can stay aero for 5-6 hours. While the P2 may be faster sans rider, if we were to need to stay out of the bars 20% of the time it would quickly lose it’s benefits. If we can get comfortable on both it will come down to price and needs.

      • Thanks guys. On paper they would both be a good fit (based on current TT bike geometry) but don’t think the LBS would get both in for me to try out. In terms of needs, I’m wondering if they are much different in terms of frame comfort over Ironman distance, ie does the Slice do what it says in terms of comfort relative to the P2?

        • The Slice is built for comfort and after doing a number of half centuries and metric centuries we can attest to the work they did to make it a comfortable bike. The P2 isnt uncomfortable by any means – just the Slice was built with that a higher design consideration while the P2 was designed with an aero first philosophy.

  5. Thanks for the great and informative review.
    I plan on purchasing the Slice this week, however, I have a question regarding size.

    I am 182cm(5’11) w/ inseam: 86cm (2’9). Which size would you go for?

    • Hi Sebastian – unfortunately as a rule we do not comment on sizing questions. As we are not able to see your specifics and how you set up on a fit bike we choose to leave that to the members of your local bike shop.

  6. So I both the 105 and put force 1x and cut the stem down like chrabot. And the thing is a masterpiece compared to the 8000 dollar tri bike I was riding. Miles come by smoother, seems for 2 grand it is really stiff.

  7. Thank you very much for the review. I got the last of the mohicans (2017 phase out model) and I really love it! Yes, it is very comfortable for long rides. I’ll be racing it this August in my first Ironman. Thanks!

  8. Picked this bike up over a year ago, partly due to your review. Wow, it is definitely comfortable and fast. Set PR at IM distance this year, averaging over 20 mph. Can be aero all day and comfortable.

  9. Still enjoy riding 2017 Sice 105, upgraded to: Profile Design cockpit, Cannondale SISL crank set from CAAD, HED Jet 6+ wheels, Garmin Vector power meter pedals, Fizik Mistica and it flies. Very comfortable and forgiving frame, surprisingly good in climbing hills. Long list of top pros (Heather Jackson, Andy Potts to name a few) were riding the same frame until Cannondale has practically left the tri business.

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