Cannondale Slice Ultegra 6800 – just in

Cannondale's lighter, faster, more practical TT bike arrives for long-term testing

When the new Cannondale Slice was launched in Hawaii last year, the American brand promised a lighter bike, more comfortable, practical and aerodynamic than its predecessor.


From the outset, Cannondale made it clear that the team designing the new Slice didn’t want to follow the recent trend of ‘tunnel vision’. Cannondale product manager, David Devine, described this as becoming “obsessed with achieving theoretical wind tunnel aero advantages at the very real expense of everything else”.

That’s not to say aerodynamics doesn’t matter to Cannondale. Indeed, the bike is claimed to be faster than the old Slice, a machine that has four Ironman World Championships to its name.

The Slice has plenty to recommend for time triallists as well as triathletes, especially those who ride longer distances or compete regularly.

Comfort and fit

First, the bike’s been designed for comfort – something that should be welcome to anyone who races against the clock on less than perfect roads, which is to say almost everyone.

Cannondale says the Slice offers more vertical deflection, and thus comfort, than most endurance road bikes. This is achieved by solid, pencil-thin seatstays, narrow chainstays and an offset dropout on the Aero Save fork. The solid seatstays make the bike illegal for UCI sanctioned events. But, in the UK at least, the bike is completely legal any non-UCI events (which most are), including CTT national championships.

The reverse of the seat tube is designed to reduce pressure drag:

The reverse of the seat tube is designed to reduce pressure drag

The rider makes up the majority of drag in a time trial, so Cannondale’s worked with fit partner Guru on the frame’s geometry and adjustment range. This could prove instrumental in enabling time triallists to find a position that best balances power output and aerodynamics. The thin carbon seatpost has two mounting points for increased fore-aft adjustability.


The Slice’s practical elements could also be speed boosters. The frame’s slack head tube angle, low BB drop and steep seat angle should aid handling – something that’s notoriously twitchy on most time trial bikes. Stable handling should also be bolstered by the Truncated Aero Profile (TAP) tubing. These tubes have blunt trailing edges, meaning less surface area to get caught in crosswinds.

The front-facing direct mount Shimano brake might not be as aero as hidden options seen on superbikes, but it’ll actually stop with decent power. There’s a matching Shimano model under the chainstays too. More powerful braking plus better handling equals faster cornering, or so the theory goes.

The direct-mount brake is designed to actually slow the bike when used:

The direct-mount brake is designed to actually slow the bike when used

Another benefit of proper brakes is their adjustability. If you’ve ever tried to adjust proprietary systems, it’s likely that you probably lost a piece of your soul in the process (and ditched another when they went out of alignment after the next ride).

Gear selection is also practical with Cannondale offering an 11-28 cassette across the range and 52/36 chainrings on all but the top two models. It’s nice to have these from the get-go rather than having to swap in easier gearing.

Cannondale’s gone for a normal stem setup, which is what you’ll get with almost all TT bikes outside the superbike category. It makes it simple to strip down for travel as well as having an easy to adjust stack with regular spacers on the fork.

Weight and spec

Then there’s the weight. The top-end Hi-Mod frame weighs in at only 1,020g for the frame, 390g for the fork. This is extraordinarily light for a TT bike and puts it in a class of its own.

An ultra-aero but heavy bike might be OK for those able to push hard enough to maintain an aero benefit uphill without their heart exploding, but weight matters to the rest of us.

The model featured here is the Slice Ultegra 6800. The bike sits just above the entry-level Shimano 105 model in the Slice range and features mechanical Ultegra gearing and Mavic Aksium wheels.

The frame weighs 1,250g, the fork 420g. The all-up weight is 8.12kg, which is still very impressive, especially compared with the weights you’ll find on other £2,500 (US$3,790 / AU$TBC) TT bikes.

The cannondale hollow si crankset runs through an oversized bb30a bottom bracket:

The Cannondale Hollow Si crankset runs through an oversized BB30A bottom bracket

The bike is specced with Cannondale’s Hollowgram SI crankset and the company’s BB30A bottom bracket. This relatively new bottom bracket standard surfaced on the 2014 Synapse and is 73mm wide and asymmetric, removing spacers on the non-drive side.

Shimano Dura-Ace tip shifters take care of gear changes via Ultegra front and rear derailleurs. The aforementioned direct mount brakes are from the same 6800 range. The brake levers are from Tektro and feature wider, comfier looking carbon levers than the Shimano alternatives.

The aerobars use a Cannondale C3 base bar topped with FSA Tri Max Team clip-on extensions. The latter appear to be the only practicality hiccup in the bike’s design, because there’s no length adjustment short of cutting the extensions down.

Fizik’s snub-nosed Tritone saddle finishes off the spec list. Despite its extreme-looking design, the Tritone is one of the comfiest TT perches out there. The rear mount also allows bottle cage attachment without additional accessories.

Fizik’s tritone saddle looks painful, but feels great:

Fizik’s Tritone saddle looks painful, but feels great

Going long-term

The small clip-on snafu aside, all the above means the Cannondale Slice could be exactly the light, comfy and practical time trial bike that this tinkering-weary cyclist has been looking for.

To that end it’ll be putting me through my paces over the next few months, both in time trial and triathlon competition, to get an idea if it lives up to its promise. As a middling, 66kg rider not pushing mega watts, the light weight certainly appeals.

Shimano’s direct mount brakes remain the best stoppers outside of Magura’s hydraulic rim brakes, which is also a key concern. The lack of faffing with them is also of the utmost importance.

As for aerodynamics, I’m never going to know how it truly compares to other bikes outside of the wind tunnel. So as long as it isn’t too far from the mark on regular test routes, I’ll happily give up some straight-line speed for comfort and cornering.


I’ll update as I go: getting a bike fit, swapping components and seeing what it’s like to live with. Next up will be first ride impressions.