Rocky Mountain Instinct Carbon 90 BC Edition first ride review£5,500.00

Leggy and efficient big-terrain all-dayer

Rocky Mountain has added longer-stroke Fox suspension, altered the linkage and upsized the ground and rider-contact components of its 140mm-travel Instinct to give the BC Edition big-terrain beef.

It’s still an efficient all-rounder and technical scrambler rather than an outright bomber, though.

Rocky Mountain Instinct Carbon 90 BC Edition spec overview

  • Frame: ‘Smoothwall’ carbon fibre, 155mm (6.1in) travel
  • Fork: Fox 36 Float EVOL FIT4 Performance Elite, 160mm (6.3in) travel
  • Shock: Fox Float DPX2 Performance Elite
  • Drivetrain: SRAM GX Eagle with SRAM Stylo 7K cranks (1x12)
  • Wheelset: Stan’s NoTubes Flow MK3 rims on Rocky Mountain (f) and DT Swiss 370 (r) Boost hubs
  • Tyres: Maxxis Minion DHF 3C Maxx Terra EXO WT 29x2.5in (f) and Minion DHR II 3C Maxx Terra EXO 29x2.4in (r)
  • Brakes: SRAM Code R, 180/160mm rotors
  • Bar: Race Face Turbine R, 780mm
  • Stem: Rocky Mountain 35 CNC DH, 45mm
  • Seatpost: Fox Transfer Performance Elite dropper
  • Saddle: WTB Silverado Race
  • Weight: 13.62kg (30.03lb), large size without pedals

Rocky Mountain Instinct Carbon 90 BC Edition frame

The new Instinct frame is single-ring specific, with a fresh fibre lay-up and big boxy tubes, which Rocky Mountain claims increases lateral stiffness by almost 50 percent.

Claimed weight for the medium size is 2,810g, including the shock, tooled rear axle and all the other trimmings. Single-sided pivot axles give neat looks (but be careful not to strip them), and there’s room for a bottle under the piggyback reservoir of the metric-length Fox shock.

SRAM GX Eagle takes care of shifting duties, with its massive 500 percent gear rage
SRAM GX Eagle takes care of shifting duties, with its massive 500 percent gear rage

Cables are all internal and the frame is compatible with Shimano Di2 batteries and Fox’s Live Valve smart suspension system. A chain retainer is bolted onto the driveside stay.

Braceless stays give all-weather room for a 29x2.6in or 27.5x2.8in rear tyre despite the relatively short 435mm chainstays. Thankfully, reach has been stretched by 45mm compared to the old Instinct and the head angle slackened to 66 degrees. The BC Edition gets a different linkage with a fixed-position shock mount rather than the concentric ‘RIDE-9’ chip of the standard bike, plus a longer-stroke shock to extend rear travel by 15mm to 155mm.

Rocky Mountain Instinct Carbon 90 BC Edition kit

Up front, the BC upgrades from a 140mm Fox 34 fork to a 160mm Fox 36 to match the piggyback DPX2 shock.

Stan’s Flow MK3s are proving to be good trail rims and the Maxxis tyres are top-spec 3C versions.

The special edition bike also gets a wider 780mm Race Face carbon bar in a 45mm stem and seriously stoppy SRAM Code R brakes. The ubiquitous SRAM GX Eagle provides propulsion.

Rocky Mountain Instinct Carbon 90 BC Edition ride impressions

While the BC is the burlier of the Instinct models, in relation to other long-travel 29ers it’s still an all-dayer rather than an all-slayer.

Although the shock is fixed in what would be the lowest and slackest position on the standard bike, the extra travel means a very tall 350mm bottom bracket (18mm higher than on the non-BC Instinct).

Rocky Mountain has also changed the suspension architecture to increase anti-squat and create a more progressive shock response. This means that, while the start stroke of the EVOL DPS shock is supple, pedalling naturally lifts the bike higher in its travel.

Add increased ‘foot feel’ to temper traction via the sticky rear tyre and you can claw up ultra-techy stepped climbs that would have you pedal-slamming or tyre-slipping on most bikes.

While the B.C. is the burlier of the Instinct models, in relation to other long-travel 29ers it’s still an all-dayer rather than an all-slayer
While the B.C. is the burlier of the Instinct models, in relation to other long-travel 29ers it’s still an all-dayer rather than an all-slayer

Although the tyres are tacky rather than rapid, they’re wide and tough enough, and the 29mm rims are sufficiently broad that you can run lower pressures for a faster roll over rough ground.

The simplified DPX2 shock still has 10 fine-tune settings in open mode, as well as an easy-to-reach ‘pedal’ setting to refine low-speed shock feel. Combined with a 30lb weight for the complete bike, this all means you can attack climbs with determination all day long.

What makes the BC Edition a conspicuously good climber can catch it out on more testing downhill sections. While the base geometry is fine for fast riding, the tall bottom bracket and high-riding suspension mean it tends to sit on top of the trail rather than suck down onto it.

That’s particularly obvious if you’re trying to carve hard across roots and rocks, where the Instinct feels precarious rather than pinned. Lowering the tyre pressures helps add some glue without killing agility, though, and on less testing terrain the steering is well balanced. Switching to 650b+ wheels/tyres would reduce the ride height.

While it’s slightly disappointing to see second-tier ‘Performance Elite’ dampers on a £5k/$5k bike, the fork and shock have a similar slightly-tight feel, which keeps things predictable, if a little rough occasionally. Shock tunes are size-specific too, which is a nice touch.

Rocky Mountain Instinct Carbon 90 BC Edition early verdict

This big-travel 29er rides high to trade descending confidence for climb and epic-ride efficiency gains.

Guy Kesteven

Freelance Writer, UK
Guy started filling his brain with cycle stats and steaming up bike shop windows back in 1980. He worked the other side of those windows from '89 while getting a degree in “describing broken things covered in mud" (archaeology). Dug historical holes in the ground through the early '90s, then became a pro bike tester in '97. Guy has ridden thousands of bikes and even more components the world over since then and can remember them all in vivid, haunting detail. Can't remember where the car keys are, though.
  • Age: 45
  • Height: 180cm / 5' 11"
  • Weight: 68kg / 150lb
  • Waist: 76cm / 30in
  • Chest: 91cm / 36in
  • Discipline: Strict sadomasochist
  • Preferred Terrain: Technical off-piste singletrack and twisted back roads. Up, down, along — so long as it's faster than the last time he did it he's happy.
  • Current Bikes: An ever changing herd of test machines from Tri bikes to fat bikes and everything in between.
  • Dream Bike: His Nicolai Helius AM custom tandem
  • Beer of Choice: Theakston's Old Peculier (not Peculiar)
  • Location: Yorkshire, UK

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