Need to know

• BC Edition gets an aggressive spec with single-ring drivetrain
• Ride 9 system lets you tune the geometry and suspension feel
• Full carbon frame with Smoothwall construction
• 120mm travel via RockShox DebonAir shock

We at mbr are suckers for a good short-travel trail bike. Done well, they are efficient, agile, responsive and offer unrivalled giggles on fast, flowing singletrack.

The Rocky Mountain Thunderbolt is one such example. It’s a small bike with big ambitions and aims to give you more of what you want and only just enough of what you need.

This is also the BC Edition, which means you get a more aggressive spec, inspired by the kind of parts picks a pro rider would make. That means a wider bar, a shorter stem, a dropper post, a longer-travel fork and a 1×11 drivetrain.

A few years ago such a focused build would have turned heads but now it’s a lot more commonplace. To be a really forward-thinking brand, you have to be pushing this kind of spec right the way across your range.

With its Smoothwall carbon frame, the BC Edition is super-light. Considering it gets a dropper post and alloy cranks, the 26lb weight is impressive. Part of the reason for this minimalism is that Rocky Mountain’s trail bikes shun cartridge bearing pivots in favour of lightweight bushings.

Unfortunately, they can’t match the low-friction performance of bearings, and the knock-on effect is a reduction in small-bump sensitivity and grip that even the RockShox DebonAir shock can’t mask.

With a test loop that included several of Whistler’s notorious Enduro World Series stages as well as numerous runs down jump trails like A-Line and Crank It Up, I had taken advantage of the Ride 9 shock mount to dial in the slackest, lowest setting offered by the Thunderbolt.

This had given me a 66.2° head angle and a 330mm bottom bracket height — good numbers. But the Thunderbolt had exhibited a wild, rodeo ride on the natural trails that had left my eyeballs on stalks. Whipping its low-mass around on the jumps trails was a lot of fun, but at high-speed it began to display a definite nervousness. Throwing a tape measure between the axles had revealed the Rocky is giving away 20mm to similar bikes on the market.

So, while it had been a demanding stage and I had asked a lot from the Thunderbolt, the diminutive wheelbase and sticky suspension definitely hindered performance more than expected.