After what has seemed like an eternity since I picked up my showroom-fresh Rocky Mountain Thunderbolt 770 (my initial impressions here: http://wp.me/p3nKds-S), I have finally been able to devote some quality trail time to adjust to my new ride and form some opinions with regards to 27.5″ wheels and the bike in general. For those of you only interested in the Coles Notes version: I’m officially a ‘tweener convert. Technical climbing prowess, more traction, and increased smoothness and momentum over rough terrain more than make up for a nominal decrease in agility and acceleration compared to a 26er.
For those of you interested in all the nitty-gritty details, first some general stats. Rocky bills the Thunderbolt as a bike for “when XC gets rowdy“. The build out of the box certainly reflects this, and while it features a respectable arsenal of higher-tier Shimano and Fox components and Stan’s Crest wheels, at just over 28 pounds it is definitely not a weight-weenie XC bike (details here: http://www.bikes.com/en/bikes/thunderbolt/2014). I rode the bike a few times in the stock configuration and was admittedly overwhelmed by its heft. Despite a strict budget, I went to work swapping a few key items to shave off a bit of weight, and in the end, a Whiskey carbon bar, Selle Italia SLR seat, ESI grips, and Schwalbe Rocket Ron tires set up tubeless brought the weight down to a more tolerable 26.5 pounds. Still not “race light” by any means, but not bad considering the full aluminum frame. Swapping out the heavy OEM tires and going tubeless saved a pound alone and livened up the bike significantly – if you can only afford one improvement, lighter tires and/or wheels will give you the most noticeable improvement in ride quality and the biggest bang for your buck.
On to the riding. Rocky describes the Thunderbolt as “An agile, playful XC bike that loves punchy, technical climbs and flowy singletrack descents“, a description that I agree with entirely. I’m typically quite a conservative rider when it comes to launching off trail features or choosing more reckless lines (old bones take a long time to heal), but the bigger wheels and bit of extra travel (120mm front and rear) really taunt and tease you to ride more aggressively. I’m getting air, and I like it. The extra traction provided by the bigger wheels certainly helps to eat up punchy, technical climbs, of which there are many in Edmonton, and I’m finding cleaning tricky sections is a great deal easier and takes less energy. Notably, if I do stall a bit while trying to overtake a large root or obstacle, it takes a lot less effort to get the bike moving again and successfully roll over the offending obstacle. Me likey. I also enjoy that the Thunderbolt likes to be (and in some cases needs to be) muscled around a bit, another reflection of Rocky’s “this is XC in BC” design philosophy. The bike is responsive yet stable, and despite a low bottom bracket, I am experiencing way less crank-arm and pedal smashing into roots and rocks than with past Rockys I’ve owned, likely a side-effect of the larger wheels and greater travel. Where in the past I would consistently clip certain obstacles and would expectantly cringe waiting for the familiar smash each time, now I can pedal through the same section cleanly with way less ratcheting and smashing, and way more smiling. Of course the bike’s grandeur isn’t completely owing to ‘tweener-sized wheels; this is my first experience with thru-axles (front and rear), a tapered headtube, and the short/wide bar/stem combo, which all certainly contribute to the ride quality and enjoyment factor aboard the Thunderbolt. Again, I’m finding myself pushing way harder and faster when coming into corners or when descending with no doubts in the ability of the bike to hold its own. I definitely don’t see my self ever reverting to skinny bars or quick releases.
Of course I do have a few complaints – what finicky cyclist doesn’t? The weight of the bike certainly holds one back on long, steady, open climbs. The Thunderbolt is clearly no match for a carbon hardtail 29er on such terrain, but then again I’m quite certain it wasn’t designed with it in mind. When after all have you ever encountered playful and flowly gravel road climbs? As a female rider, I also find the bike’s weight starts to become a challenge as I become fatigued – you might say, “when I gots no muscle left, I gots no hustle left” with this bike. The rear suspension of the bike is also very active when in trail mode – I find myself using the dual lockout (climb mode) way more than I initially thought I ever would, locking out on anything smooth, whether it be flat or climbing. Not a big deal if you’re always on rolling, techy, obstacle-laden trails (as the bike is designed for), but the bobbing is noticeable, and the constant button pushing to attain a more efficient pedal stroke can be a bit tiresome when riding highly variable terrain or in race situations. Finally, and not uncommon among small-sized full suspension frames, it’s a tight squeeze for a water bottle – a side loading cage and small bottle are required to avoid unsuspectingly flicking the rebound dial while indulging in liquid refreshment.
All in all, I’m happy to say I’m having a ton of fun on this bike so far. It’s not built for hammering up gravel roads, so if that’s what you’re into you’re probably going to be happier on a 29er. If you’re more like me though, the bike is a blast to ride where it counts most – on punchy, rolling singletrack. If that’s where you’re in your element, this is a great bike for it, and I would highly recommend it. Additionally, I would certainly advocate to shorter women and guys to try out 27.5 wheels – the benefits of the platform far outweigh the small loss in agility compared to a 26er, and the bike actually fits someone my size properly unlike a 29er. Yes, it is a bit hefty for an XC racer, but then so am I, so you could say we’re a perfect match.