First Ride Review: Cannondale Scalpel-Si Carbon 3

Cannondale have been brave with the new Scalpel-Si. While many manufacturers remain committed to the traditional cross-country / marathon bike formula, Cannondale have clearly taken a page from the progressive geometry book, packaging it into a serious race bike. We can only hope that this translates to fewer queues and more smiles on the single track at our local marathon events.

The Frame

Cannondale have applied what they call System Integration (Si) to the Scalpel range to create a complete package that works seamlessly. They have tailored the set up across the size curve including 650b wheels on the XS and S, and women’s sizes.

While still plainly a Scalpel, the Scalpel-Si has brought the design up-to-date with straighter lines and a refined look. Most obvious is the new suspension design which tucks part of the rear shock into the top tube, resulting in an elegant lining-up of the seatstay, shock and toptube. There is also now space for two bottle cages in the front triangle.

It’s not just all looks either, Cannondale claim that the new Scalpel-Si carbon frame is one of the lightest dual suspension mountain bike frames in the world with a frame weight of just 2,118g including the shock, hardware, and axle on the Hi-MOD version. Which, according to Cannondale’s numbers, make it 240g lighter than the 2016 Specialized S-Works Epic frame.

The new internal cable routing system plays its part in keeping the Scalpel-Si looking neat. The ports on the redesigned head tube provide an easy path for the cable to enter the frame while also holding the cable neatly in position with a “lockable system”. Should you desire to run a Shimano Di2 drivetrain, Cannondale have designed a system for mounting the battery inside the top tube just above the shock mount. There is also provision for an internally routed dropper post which, thanks to the routing system, can be done while running a Di2 drivetrain.

While the bike may still look much like the Scalpel of old, the geometry has seen a complete overhaul with a number of changes resembling what we’ve seen happening on trail bikes. The previous Scalpel was a take-no-prisoners race bike geared at covering distance and conquering climbs. While the Scalpel-Si still claims to do the same, it acknowledges the technical challenges of modern cross-country courses with a number of dramatic geometry changes to help riders negotiate the tough stuff.

To improve handling and traction, Cannondale shortened the chainstay length by just under a centimeter to 43.5 cm (on the 29er models) in part thanks to the new, straight seat tube. In order to squash the wheel in a small space (and without having to implement Boost 148), Cannondale shifted the chainrings and front derailleur 6 mm outboard to create more space. At the same time, they adjusted the rear triangle to match, allowing for a more evenly dished rear wheel – resulting in more strength and stiffness. Cannondale call this Asymmetric Integration Offset Drivetrain (Ai).

To complement the handling improvements of shorter stays, the head angle has been slackened to 69.5 degrees from around 71 degrees (depending on frame size) on the previous Scalpel. A slacker head angle generally puts the front wheel further in front of the bike which allows the fork to soak up more of the trail and helps to stop the rider pitching over the handlebars. To counter the sluggish handling a slacker angle might cause at slow speeds, Cannondale have custom designed the Lefty with a 55 mm fork rake through the use of an off-set front axle. Cannondale are calling this combination their OutFront steering geometry. The seat tube angle remains 73.5 degrees, keeping the weight over the pedals for power and traction. The Scalpel-Si also sees a slightly lengthened reach which allows Cannondale to fit a shorter stem for more accurate control.

Cannondale have given up on their proprietary steerer standard in favour of a slightly more common 1.5” steerer, which should improve the aftermarket stem options for the Scalpel-Si. The new steerer sizing means that older Lefty forks are not compatible with the Scalpel-Si. The changes in the Lefty’s rake also means that the new Lefty hub has seen some sizing changes and, as a result, is not backward compatible, although the older hubs can be used on the Scalpel-Si with an adaptor.

The rear suspension on the Scalpel-Si has also gone under the knife. The previous Scalpel had an awkward bolted together collection of parts fixing the seat stay to the rocker. The new LockR system uses an expanding thru-axle connecting both sides as a single piece without the need for special tools. To improve the performance of the flexible seat stays, flat brake mounts are moved from the seat stays to the inside of the chain stay to allow for better flex. When suspension damping isn’t what you want, Cannondale worked with RockShox to make an integrated single-push lockout control for the Lefty and shock. The rear lockout travels internally down the top tube which contains the top of the shock.

Components

Fork

The Scalpel-Si Carbon 3 comes fitted with the Lefty 2.0 boasting XLR Isolated Damper Technology with XC+ tune and XLoc Full Sprint remote. The XLoc Full Sprint does an excellent job of locking the fork out, as it will go from plush to just about rigid with the push of the button. The general stiffness of the Lefty 2.0 puts Rockshox’s and Fox’s latest XC offerings to shame which is not what one would expect from a fork that is not really a fork. The Lefty’s small bump performance is good without diving through its travel at the first sight of uneven terrain. Sure, there is still only 100mm, but it handles what it has on offer very well.

On my first ride, there was a slight knocking noise sitting inside the fork’s first 20 mm of travel. This turned out to be the lower guard and I was able to remedy a fix trail-side.

Drivetrain

A mix of Shimano XTR and XT is powered by a Cannondale Si crank with a 32T Ai SpideRing. As mentioned in my review of the Silverback Sesta, I find the 11-42 Shimano cassette ratio too narrow for a 1x drivetrain on an XC bike. With the 32T chainring, I was spinning out at around 35km/h leaving me to coast it out. Fortunately, the Scalpel now comes specced with Shimano’s 11-46 which will help a great deal as. This range will allow most riders to up the chainring to a 34T and for the fitter amongst us to bump that to 36T.

Brakes

Shimano XT M8000 brakes are paired to 160mm front and rear rotors. Stopping power was good and the rotors did well at slowing the bike down. Fitting beefier tyres (and resulting higher speeds) did show that I would probably go to a 180 mm rotor in front sooner rather than later if only to be on the safe side.

Tyres

The only specification choice on this bike that I can fault are the tyres. Schwalbe’s LiteSkin tyres are simply too flimsy and thin for South African conditions. Their paper-thin sidewalls caused the tyres to roll on their carcass. The only partial solution is to increase tyre pressure which leads to a loss of grip and traction, and an unnecessarily hard ride. With the overall weight of the bike already very competitive, I see no need to compromise with these tyres – especially as they only offer a 90 gram saving per tyre over the Snakeskin model.

Wheels

The rims are Stan’s new Crest MK3 with an inner diameter of 23 mm which, according to Stan’s Notubes WideRight philosophy, are good for tyre widths up to 2.25. Weighing in at just 364 grams per rim, the rims play their part in the bike’s overall speed, but they do carry an 86 kg rider weight limit. They are laced to CZero straight pull hubs using Grand Forza double butted spokes with Cannondale’s unique Ai offset dish. With the LiteSkin tyres fitted one cannot be sure whether any “movement” is coming only from the tyres or the wheelset. The swap to beefier tyres did however prove that the wheels and frame are suitably stiff and no cause for concern.

Cockpit

To round off the package, the Scalpel-Si comes with a 760mm carbon handlebar and 90mm stem. It was great to see this combination on a cross-country race bike. It suits the bike perfectly and offers great control and composure to a segment that is known for twitchy or nervous bikes. The Cannondale branded grips are comfortable and stayed secure through the roughest sections, thanks to inner lock rings.

Saddle

Prologo’s Zero II STN has been surprisingly comfortable, after some recent abuse by other saddles following acclimatization to Specialized’s Power saddle. Although the basic shape is similar to other cross-country saddles, the Prologo Zero seems to have got the mix just right.

On the Trail

I tested the Scalpel-Si on the following trails:

• Bottelary Hills (Green and Red Loop starting from Zevenwacht)
• Meerendal
• Bloemendal

The main pivot located just above the chainring, along with what feels like a relatively stiff compression tune on the shock, gives decent pedaling characteristics when the trail points up. Under load the rear feels stiff, not giving away any hard-earned watts. There is no denying that the Scalpel-Si is a great climber. Whether grinding away or putting the hammer down, every pedal stroke translates into forward motion, making light work of long ascents. The bike’s excellent pedaling manners meant that I could leave the suspension fully open and active at all times. This helped with extra grip and traction and no need to remember to flick a switch or push a remote when the party starts.

Any concerns about the slacker head angle turning the front wheel into a wanderer can be dismissed. It stayed planted and on track over the steepest climbs and showed no signs of ill-manner over technical, uphill sections. I’m sure the 55 mm offset fork and 73.5° seat tube angle play a big part in this. What all of this means to you is the ability to focus on choosing the best line and getting to the top in the fastest possible time.

While it’s still very much a race bike, this new generation Scalpel-Si is fun and capable enough to ride all the time and a great choice for today’s gnarly XCO courses. Drop into single track and you will soon notice that the Scalpel-Si feels more solid and planted than you would expect from a cross-country race bike. When the trail gets steep and fast, the bike has no problem building speed. The 69.5 degree head angle, when paired with the 55 mm fork offset, long-ish front end, shorter stem, and wide handlebar, adds to high-speed stability and low-speed control in a way that has previously been reserved for trail bikes. The bike’s overall handling feels neither nervous nor lazy and that goes for uphill, carving single track or navigating a section steep enough to tyre buzz your baggies. Bigger jumps, rock gardens, and drops were handled with poise.

Where the Scalpel-Si did run falter was when I pushed it hard around berms or corners. This was down to the LiteSkin Schwalbe Racing Ralph tyres. Fortunately, this is an easy fix (but an annoying cost). The chances are you will be converting to tubeless anyway. After a ride or two of fighting a slow puncture and optimum tyre pressures to counter the tyres carcass roll, I moved a set of Onza Ibex tyres over from another bike. Whoa Nelly! Although they would not be my first choice for a 100 mm race bike, they certainly did prove just how capable the new Scalpel-Si is. In terms of feel and handling, I can say it easily feels closer to some 120mm trail bikes on fast flowy trails and descents. The difference is that you will feel much fresher when you get to the top, thanks to its climbing prowess. Make no mistake, this is no short travel hooligan bike, but the confidence that it has inherent in its design means it will happily tackle bigger terrain with control.

Verdict

We only had the bike for 10 days and in no way are we trying to sell this as a full blown review. We have however put enough dirt on the tyres in that time to get a good feel for the bike and to know that this is not the same cross-country bike of old. The specification selection (apart from the tyres) along with the tweaked suspension and progressive geometry, make the new Scalpel-Si a versatile short-travel weapon. It is one of the few 100 mm race bikes out there that will be happy to run with most 120 mm trail bikes through the twisties (along with the Pyga Stage we recently reviewed). Fit a dropper seat post and some grippier tyres and the Scalpel-Si Carbon 3 will have you reach for baggies come Saturday morning.

That it is fast is undisputed, but more importantly is the ease with which it handles its new-found speed.

Cannondale Scalpel-Si Carbon 3 Full Specification:

• FrameScalpel-Si, 100mm, BallisTec Carbon, Zero Pivot seatstay, PF30, 1.5 Si head tube, Ai Offset
• ForkLefty 2.0, 100mm, XLR Isolated Damper Technology with XC+ tune and XLoc Full Sprint remote, 55mm offset
• ShockRockShox Monarch XX, 100mm, Full Sprint remote
• RimsStan’s Notubes ZTR CREST, 32 hole, tubeless ready, 23mm ID
• HubsCZero Straight Pull, Lefty 60 front, 39-point engagement rear, 142×12, 28h (Ai Offset dish – Rear)
• SpokesGrand Forza Double Butted (Ai Offset dish – Rear)
• TyresSchwalbe Racing Ralph EVO Snakeskin, 29×2.25″, folding, tubeless ready [Also tested with Onza Ibex]
• CrankCannondale HollowGram Si, hollow forged, BB30, 32t Ai SpideRing
• Bottom BracketCannondale Alloy PressFit30
• ChainShimano CN-HG601, 11-speed
• CassetteShimano XT, 11-42, 11-speed
• Rear DerailleurShimano XTR Shadow Plus, 11-speed
• ShiftersShimano XT, 11-speed
• HandlebarCannondale CZero flat, Carbon, 760mm
• GripsCannondale X1 Single Lock Grips
• StemCannondale C1, 6061 Alloy, 1.5″, 31.8, -5 deg.
• HeadsetCannondale HeadShok Si
• BrakesShimano XT, 160/160mm
• SaddlePrologo Zero II STN
• SeatpostCannondale C2 Carbon, Micro Adjust, 31.6x350mm (S,M) 400mm (L,X) [Tested with a Fox Transfer]
• SizesXS, S (27.5″) M,L,XL (29″)
• ColourJet Black w/ Nearly Black and Charcoal Gray, Matte or Berzerker Green w/ Jet Black and Charcoal Gray, Gloss
• Retail PriceR 74,999