We've seen race-ready 12kg (26lb) XC full sussers for half the price of the Spark 10, but trimming weight and adding speed significantly bumps up costs. The top of the range £4,499 Spark Ltd weighs under10kg (22lb); for £700 less, the Spark 10 tips the scales at 10.5kg (23lb); the cheapest in the range is the 11.4kg (25lb) Spark 30, at £2,399.
So how have Scott built this bike? To start with, the unique mainframe and rear triangle uses carbon more extensively than any full susser we've ridden. Scott say the HMF carbon, produced just for them, increases stiffness by 20 per cent in areas where extra rigidity is needed. The result is low weight without a flexy ride. An 'integrated moulding process' (IMP) allows Scott to make a onepiece head/top/down tube frame section with reinforced areas built-in where required. Extra grams are shaved via the Naked (no cosmetic weave) finish, and the DT Swiss-produced Nude shock weighs a scant 240g. Looking at the detail of the frame, it's hard to imagine where frame manufacturers can go next.
The carbon swingarm (seatstay pivot) is very effective in the way it uses the sealed bearing rocker linkages to drive the shock, but it's the shock that'll attract most attention. A bar-mounted thumbshifter lets you shift between 110mm (4.3in) All Travel and 70mm (2.8in) Traction Control modes, and a Lockout mode still allows the shock to budge if you hit something.
The componentry is all top dollar. A 100mm (4in) Fox 32 fork with lockout sits up front; the gears are SRAM X.O with a Shimano XTR front mech. Our bike had XTR cranks too but a Truvativ Noir carbon crankset should be on final production bikes. Avid Juicy Ultimate carbon levered disc brakes perform stopping duties and a super light DT Swiss 240 wheelset is shod with Scott's own grippy but fast rolling 2.2in Ozone treads. The oversized carbon bar and seatpost are Ritchey WCS and the perch is a Selle Italia.
The Spark is one of those rare bikes that appears to make steady trail riding almost effortless. That's due partly to its low weight, partly to its incredibly forgiving ride character. It's not just a thoroughbred race bike: the plush suspension, big tyres, riser bar and comfy ride posture mean it instantly flatters the abilities of intermediate riders. With the shock in Lockout mode, it's as precise and lively as a hardtail. When the going gets rough, shifts between All Travel and Traction Control suspension modes become almost as intuitive as gear shifts after the first few rides.
The 13in bottom bracket height means you need to take care pedalling through corners in the All Travel setting, but you can really let loose across rocks and roots. In Traction Control mode, it develops the distinctive nimblesse of an XC race bike. It shimmers its way through trail debris, taming dodgy lines without a glimmer of speed lag and exhibiting taut and snappy handling.
For such a light carbon full susser, it's surprisingly stiff. Over and above that, it's incredibly fast. £3,799 fast? That's up to you.