Whilst 140mm 27.5in wheel bikes aren’t grabbing many headlines of late, bikes like the new Rocky Mountain Thunderbolt BC are what most riders still want.

>>> New Rocky Mountain Instinct BC Edition 155mm travel 29er

Rocky Mountain Thunderbolt BC need to know

• 27.5in wheel
• 140mm travel
• Increased anti-squat
• Size Specific Tuned damping
• Max tyre clearance is 27.5 x 2.5
• Bearings at all pivots, including at the lower shock mount
• Lighter, tooled rear axle, with an updated axle nut for a more intuitive assembly
• Improved cable management including large head tube and down tube access ports, full-length shift housing, and internally routed shift housing and brake lines the front triangle housing
• Seat tube lengths have been adjusted to accommodate longer dropper posts at maximum insertion.
• Integrated “Spirit Guide” chainguide, with 2-bolt ISCG05
• 1x optimized design with wider main pivot
• Lower standover height
• One-piece seat stays, new envelope, and updated layup
• Boost
• Metric
• All sizes fit a water bottle in the front triangle with any reservoir shock currently on the market
• Sizes: XS-XL
• Weight: Thunderbolt Carbon 90 BC: 12.57kg (27.7lbs), size Large
• SRP: £5,499.99

The last time we test rode a Rocky Mountain Thunderbolt (back in 2016) our verdict was “the diminutive wheelbase and sticky suspension definitely hindered performance more than expected”. So we’re pleased to see the new geometry. Here’s hoping the move to metric shock and bearings at all pivots seals the deal on a promising package.

The Rocky Mountain Thunderbolt BC Edition uses a longer stroke shock to yield 140mm of travel. There is a non-BC Thunderbolt model with 130mm travel front and rear but we can’t imagine why anyone would go for one of those over the BC version.

Rocky Mountain Thunderbolt

Oh yeah, the non-BC ‘Bolt costs shed loads less as a full build: £3,199.99.

We can’t help think but it’d be great to see a Rocky Mountain Thunderbolt BC in the circa £3k build too. Maybe one day…

Press release

Improved suspension performance

We’ve flattened out the rate curve to directly increase the amount of useable travel, while maintaining mid-stroke support and making small-bump performance even more sensitive. Higher anti-squat values dramatically improve pedalling efficiency.

Next generation features

Comprehensive evolutionary updates across the platform include features like tooled axles, single-sided bearing pivots, integrated “Spirit Guide” chainguide, and metric shock compatibility.

Updated RIDE-9TM

Our RIDE-9TM system provides a wide range of geometry and suspension adjustability; it has been moved into the link for lighter, narrower packaging.

Progressive geometry

To add control and descending capability, we’ve increased reach, slackened the headtube angle, and lowered the bottom bracket. We’ve slightly lengthened the chainstays to improve climbing traction and used a moderately steep seat tube for further climbing performance.