The clue is in the name — this one is all about the mass. The SL is Fuji's pure climber, and even in its second-tier 2-series incarnation, it claims a frame weight of 900g or less. A spec with modest and functional in-house finishing kit and matching wheels is completed by Shimano's Ultegra Di2 groupset. It's visually more restrained than some of its rivals, but does that translate into a boring ride?
When Fuji launched the SL line at the 2015 Vuelta a España, the claimed 695g weight of the 1-series frame put it in a very select group of ultra-light machines. The secret behind this impressive figure is what Fuji calls "high compaction moulding" (with both internal and external moulds) which produces a frame that's just about as finished on the inside as it is on the outside. That means there's no superfluous material adding weight, and the process helps ensure the even distribution of resin within the carbon matrix, producing the strongest possible frame. (NB: in the video version of this review we incorrectly state that all SLs benefit from this technology. In fact, it is only the 1-series that uses this particular manufacturing technique.)
Further significant savings come from a reduction in the number of sub-assemblies that make up the frame. The SL's predecessor, the Altimira, had eight bonded joints where one tube meets another. The new bike has just four thanks to improved manufacturing techniques that allow the seatstays and chainstays to be made as two one-piece assemblies, rather than four separate parts.
Unfortunately, the 1-series is far from cheap, which is where the working-man's 2-series comes in. The SL 2.1 gets a frame that's a tiny bit heavier (it weighs between 850g and 900g with paint, apparently) than the top-tier machine, but which shares the same geometry and outward appearance.
Fuji naturally claims all sorts of improvements in stiffness over its predecessor too, the most significant of which is in the fork, which uses a "re-inforced I-beam" (essentially a central rib running down the inside of each hollow leg) to resist flex.
Like many manufacturers, Fuji varies its carbon layups across the sizes to account for the stiffness needs of different sized riders. More unusually, they also vary tube diameters, and the geometry hasn't been neglected either, with the three smallest sizes getting a larger fork offset to keep trail figures (which impact handling) more or less consistent across the range.
Despite all this cutting-edge stuff, the SL's frame is actually quite understated, with appealingly clean and simple lines and a tasteful paintjob that sparkles delightfully on close inspection.
The tubing is big in the usual places (bottom bracket, downtube, headtube) but it's nowhere near as gargantuan as some of its rivals. Out back, the flattened seatstays promise compliance, and in side profile they are exceptionally slender even compared to those we'd conventionally describe as 'pencil-thin'. The SL's cabling is all internal and it's rendered particularly neat thanks to some nice injection-moulded cable stops.
Along with Shimano's ever-reliable (and shiny) Ultegra Di2, Fuji's in-house Oval finishing kit and wheels tie together a package that's notable for its quiet competence. With the possible exception of a rather soft saddle, it's all well chosen, and we particularly appreciated the slight sweep on the tops of the handlebars.
The 733 clinchers aren't particularly flashy, but they earn points for being a little bit wider than bog-standard rims, offering a small but welcome boost to tyre volume, and they offer the option of tubeless conversion.
Out in the world, the SL is a pure climbing machine of the old school, with a character not unlike that of the wonderful Ridley Helium SL, or that other perennial favourite the Scott Addict.
It doesn't box you about the ears with its stiffness, but the combination of solidity under hard pedalling and what we can only describe as poise make for a bike that feels lively and willing on the ups. Although the bike isn't Earth-shatteringly light, it feels as though it is, with the daintiness of the tubing being reflected by the daintiness of its handling.
Downhill that feathery persona can occasionally lend a slight skittishness, but never enough to warrant complaint. It's also pretty darned comfy for a race bike as long as you can hack the position — the SL's geometry puts it very much in the realm of competition. The reach on our medium test bike isn't exceptionally long at 385mm, but a 135mm headtube offers just 540mm of stack — this is no upright sportive machine, and most riders won't be slamming that stem.
If the fit works for you however, it's a peach of a bike. Even in its fractionally de-tuned 2-series incarnation, it joins the ranks of some outstanding lightweights. If you like your roads with gradient warning signs, give the SL a go.
Fuji SL 2.1 spec
- Weight: 7.3kg (54cm)
- Frame: SL C10 carbon
- Fork: SL FC-440 full carbon
- Gears: Shimano Ultegra Di2 52/36, 11-28
- Brakes: Shimano Ultegra
- Wheels: Oval Concepts 773 clincher
- Finishing kit: Oval Concepts 310 bar, 313 stem, 905 carbon-wrapped seatpost, R500 saddle, Vittoria Zaffiro Pro Slick 25mm tyres