Hopping on the Thunderbolt BC, it was pretty quickly apparent that it bears some similarities to the longer-travel Altitude Rally Edition that I’d ridden previously. The suspension has a very firm feel to it, even when sag is set in the 25-30% range.
I attribute a lot of that feeling to the bushings that Rocky Mountain uses. Most companies are using a traditional sealed bearing in their rear suspension pivots, but the Thunderbolt (along with most of Rocky Mountain’s other bikes) gets bushings. The downside of those bushings is that there’s some extra friction in the system, which seems to keep the suspension from being as supple over smaller bumps.
There are, however, some upsides of the bushings that are worth noting; primarily, they make for a very stiff frame without adding much weight. The Thunderbolt was noticeably stiffer laterally than other bikes in this class, which is particularly impressive since the Thunderbolt is a pretty light bike.
Rocky Mountain has also done a good job of making the bushings a bit more maintenance friendly by including grease ports on all of the pivots. A bit of regular maintenance will keep the bushings running smoothly, and they should last as long as normal sealed bearings.
On the trail, that taut rear suspension made for one of the less forgiving bikes I rode at Interbike this year. While the geometry didn’t feel unstable, and the frame certainly wasn’t flexy, I found that the frame would get bucked off line relatively easily. Most of this, I think, comes from the less-than-compliant rear end, and this echoes the issues I had with the Altitude last year.
Perhaps more time spent fiddling with the shock would have helped things out, but on most other bikes that were running a Monarch rear shock (which was most of the bikes I rode at Interbike), I felt like the quick, initial setup got me 90% of the way to settings that I was happy with. On the Thunderbolt, however, I felt like there was a lot of room for improvement, which leads me to believe that it’s not something that’s ultimately going to be fixed all the way via the shock settings.
That said, the relatively firm suspension is an advantage in some situations. It’s always a tradeoff on full suspension bikes to get a rear end that’s supple over small obstacles, yet also efficient when pedaling. Rear suspension that’s too soft can feel a bit unstable and wallowy. The Thunderbolt’s suspension definitely doesn’t have those issues; while it’s not particularly active, it didn’t bob much, so on smoother sections of trail, it felt pretty efficient.
I also found that the Thunderbolt did really well on technical climbs, and may have been the best bike I rode in that regard. It was supple enough to not get hung up on rocks, but it didn’t feel like all of my effort was getting sapped by a bouncy rear end.
The Thunderbolt BC Edition gets some credit for being a light, stiff bike that’s quite adjustable. It’s not as supple or comfortable as something like the Transition Smuggler or the Santa Cruz 5010, but for some riders, that won’t be a problem. It has more of a racy, XC-feel, but wrapped into a package that has the geometry to tackle steeper, more technical trails.
To some extent, this is the bike that I wanted the Cannondale Habit to be. The Habit is similar in that it’s a bike with XC-race tendencies wrapped into a slacker, more aggressive package, but I ultimately wasn’t a huge fan of the Habit because it was so dang flexy. The Thunderbolt BC seems to have similar intentions, and it’s quite a bit stiffer. It’s also heavier than the Habit, but I still wouldn’t call it overweight for this class of bike.
Like the Habit, I think the Thunderbolt will appeal most to riders who are coming from a more XC-oriented background, but looking to bump up to something that can tackle a wider variety of trails with ease. The Thunderbolt BC doesn’t have that mini-DH bike feel to it, but it can still handle tech without too much trouble, and it does so while retaining a more efficient feel than some of the other bikes in this category.