Available in aluminium and carbon in a wide range of specifications, including a BC Edition meant for even harder riding and a frame only option, there is a Thunderbolt for most budgets and rider. Rocky Mountain have opted for bushings rather than bearings for their lower weight and increased lifespan. There are grease ports to make servicing the bike quick and easy which will increase the life of the bushings and save on maintenance costs. Cartridge bearings have completely been eliminated from the Thunderbolt's pivot locations. This was made possible thanks to Rocky Mountain's new Pipelock main pivot. The Pipelock uses an expanding collet housed inside the large diameter hollow axle to lock the axle into the frame while also applying even pressure to the bushings making for a stiff and responsive frame.
As is becoming increasingly common, internal routing is used on the Thunderbolt. The rear derailleur housing and the hydraulic hose for the RockShox Reverb run inside the downtube while the rear brake is routed outside the frame. A screw-on access plate is located on the downtube close to the bottom bracket to allow easy access to the internally routed housing, and it also makes the bike compatible with Shimano's Di2 electronic shifting system by creating a spot to mount the battery. There is room for a full size water bottle to fit inside the front triangle, and another one can be carried on the underside of the downtube.
The bike's geometry and suspension feel can be altered using Rocky Mountain's Ride-9 shock mount system. By unscrewing a bolt and changing the position of the two inserts located at the shock's forward mounting point, riders can choose from a total of 9 different options, selecting everything from a steeper, more plush setup, to one with the slackest head angle and most progressive suspension feel. The head angle can range from 67.2° to 68.4°, and the corresponding seat tube angle goes from 73.7° - 75.3°.
The Smoothlink suspension, a four-bar system which, unlike the Horst Link, places its chainstay pivot above rather than below the axle. Rocky Mountain claims it keeps the bike active across a wider range of gear ratios and enhances bump absorption without affecting pedaling efficiency. During my time on the bike I did not notice any signs to proof otherwise.
Fork: With a 120mm worth of travel on offer the Fox 32 certainly feels stiffer than it does at 140 or 150mm, but when pushed hard it still shows signs of flex. A RockShox Revelation would be my cure for this or for those who plan to hammer their Thunderbolt day in and day out, the BC Edition with the 130mm Pike will be a better option.
Drivetrain: A 2x10 Race Face Aeffect SL crank powers a mixed SLX/XT drivetrain that performed flawlessly throughout the review period. Shifting was good and the cranks stiff enough to not give away anything the frame puts on the table.
Brakes: Shimano's SLX is the brake of choice on the 750 MSL. I would run 180mm front and rear to keep the speed the bike is capable of in check when needed. Other than that I was happy with them and they certainly do offer great value for money.
Seatpost: Another bike, another RockShox Reverb that just gets on with it and works as advertised. The only thing to note here is I prefer a right hand lever mounted on the bottom of the left hand side of the grip. It is easier to reach the lever with your thumb and requires less movement in the wrist meaning you will be gripping the handlebar even when actuating the dropper.
Wheelset: The Wheeltech Helix TR25 (by SUNRINGLÉ) rims are tubeless compatible. Laced to Shimano Centrelock hubs they are functional rather than headline grabbing. At 20.8mm internal width and 24.8mm external, I found them on the narrow side, but they do appear capable of outlasting many a gnarly trail.
Tires: The 750 MSL comes stock with a Maxxis Ardent in front and a Maxxis Ardent Race in the rear. The bike I rode was shod with an Onza Ibex 2.25 front and Vittoria Barzo 2.25 rear. It was my first time riding the Barzo and felt it was a good fit for the Thunderbolt. Unless you are running a pure XC rear tire or semi-slick, you will be hard pressed to find a tire that offers the balance of speed and grip of the Barzo. Under hard braking it does lose grip and slide, but it is predictable and within limits of what you would expect from the tread design.
The Onza Ibex is a great fit for this bike. Offering grip in spades without sacrificing out-right speed.
Saddle: WTB's Volt Race is a comfortable saddle to spend a day on with good support and a pressure relief channel that runs the length of the saddle.
Full Specification[spec_list][spec_list_row='Frame']Smoothwall Carbon. Bc2 Pivots & Grease Ports. Pipelock Main Pivot. Press Fit BB. Ride-9 Adjustable Geometry & Suspension Rate. Di2 Ready.[/spec_list_row][spec_list_row='Size']XS - S - M - L - XL[/spec_list_row][spec_list_row='Fork']Fox 32 Float Fit4. 120mm. Rebound / Firm - Medium - Open Settings / Tapered Steerer[/spec_list_row][spec_list_row='Shock']Fox Float DPS Remote Custom Valved. Smoothlink Design 120mm. Rebound / Remote Firm - Medium - Open Settings[/spec_list_row][spec_list_row='Headset']FSA Orbit C-40: IS42mm Top / 52mm Bottom Tapered[/spec_list_row][spec_list_row='Stem']RMB 6° X 60-80mm[/spec_list_row][spec_list_row='Handlebar']Race Face Evolve 1/2 Rise 31.8mm X 750mm X 9° Sweep[/spec_list_row][spec_list_row='Grips']Rocky Mountain Lock On XC[/spec_list_row][spec_list_row='Brakes']Shimano SLX Hydraulic Disc 180/160mm[/spec_list_row][spec_list_row='Brake Levers']Shimano SLX I-spec Shifter Mount[/spec_list_row][spec_list_row='Shifters']Shimano SLX Rapid Fire I-spec 2x10spd[/spec_list_row][spec_list_row='Front Derailleur']Shimano SLX E Mount 2x10spd[/spec_list_row][spec_list_row='Rear Derailleur']Shimano XT Shadow Plus Direct Mount 10spd[/spec_list_row][spec_list_row='Cranks and Chainrings']Race Face Aeffect Sl Cinch 170-175mm 38/24T 2x10spd[/spec_list_row][spec_list_row='Bottom Bracket']Race Face Team XC Press Fit[/spec_list_row][spec_list_row='Cassette']Shimano HG50 11-36t 10spd[/spec_list_row][spec_list_row='Chain']Shimano HG54 10spd[/spec_list_row][spec_list_row='Front Hub']Shimano / Centerlock / 32h / 15mm Axle[/spec_list_row][spec_list_row='Rear Hub']Shimano / Centerlock / 32h / 12 X 142mm Axle[/spec_list_row][spec_list_row='Spokes']WTB 2.0-1.8 Butted[/spec_list_row][spec_list_row='Rims']Wheeltech Helix TR25 Tubeless Compatible By Sunringlé[/spec_list_row][spec_list_row='Tires']Maxxis Folding F: Ardent 27.5" X 2.25" R: Ardent Race 27.5" X 2.2"[/spec_list_row][spec_list_row='Seatpost']Rockshox Reverb Stealth 30.9mm X 350-420mm[/spec_list_row][spec_list_row='Saddle']WTB Volt Race[/spec_list_row][spec_list_row='Weigth']12.6 kg[/spec_list_row][spec_list_row='Retail Price']R62,900[/spec_list_row][/spec_list]
- Fully Di2 compatible with integrated battery stealth port in down tube
- Internal cable, shock, and stealth dropper post routings keep cables neatly stowed
- Easy internal cable management with down tube stealth port
- 142mm E-Thru rear axle increases stiffness
- BB92 pressfit bottom bracket provides maximum lateral stiffness
- Grease ports on BC2TM and PIPELOCK pivots allow for fast and easy maintenance
- Travel: 120mm (F) / 120mm ®
- Wheel Size: 27.5"
- Intended Use: XC Trail
On the Trail
Heading out on my first ride, I was a little worried about the bike's trail and single track manners as it proved to be a very good climber. Once dialled te rear suspension offers a great balance between pedaling platform and small bump sensitivity.. Tackling technical climbs on the Thunderbolt turned out to be a stand out feature. It chows loose ascents with conviction and makes light work of sections that would otherwise have left you standing next to your bike.
The Thunderbolt shows even more speed when pedaling along on flowing, rolling trails. Even in the slackest setting there are no signs of compromise and it is happy being a mile-muncher. Hit some single track and the Thunderbolt comes alive. For a bike that is stable at speed it came as a bit of a surprise just how agile it is. Direction changes come at breakneck speeds if you so wish. There are no signs of it being twitchy or nervous which is a testimony to its sorted geometry and component spec. The handlebar at 750mm gives enough leverage to manoeuvre around and through the tightest sections.
Look closer at the Thunderbolt's numbers and you will soon understand why it is so easy to flick the bike around and get the front wheel off the ground for a manual. Super short chainstays (422mm) adds a big doze of fun to the Thunderbolts character.
Amazingly enough none of this came at the expense of cross-country speed. It is light and stiff enough to be raced on weekends with the ability to flick it into racing mode with the RIDE-9 system, you won't feel like you are riding a cumbersome trail bike. The ability to change the geometry to suit a racing stance is a big bonus. Reach of the size Large we had on review is good at 443mm in its slackest setting and 460mm in its steepest setting. Add this to the pedal friendly 73.7° - 75.3° seat angles and you have a bike that is as suited to technical trail riding as it is to racing.
Cross-country racers should sit up and take note of this bike. With courses becoming increasingly technical and the usual open road sections of marathon racing making way for twisty sections, the Thunderbolt could be a great weapon as it gets up to speed fast and holds momentum well.
The Thunderbolt 750 MSL is one of the first bikes I have ridden that felt like it had the attitude of a 26" with the speed of a 29" bike. Whether blasting through gnarly rock gardens, around tight switchbacks going up or down or giving it gas on fast, open sections this bike is happy to play along and do so with confidence. If it was a car the Thunderbolt would be a pocket rocket - punching above its weight class and bringing sport car performance to an everyday car. The GTI of mountain bikes.
From the manufacturer
Named after its lightning quick agility, the 2015 Thunderbolt MSL dominates on a variety of terrain. Equally at home on long, technical climbs as it is flowy singletrack descents, it’ll have you powering through the rough stuff and popping off every trail feature you lay eyes on. The all-new SMOOTHWALL carbon frame on Thunderbolt MSL models represents a major milestone for Rocky Mountain: by using our new PIPELOCK main pivot we have removed all traditional bearings from the frame. This combined with grease ports in key pivot locations results in a stiffer, lighter, and lower-maintenance bike.
Lightning fast, the Thunderbolt is our vision of a perfect XC trail bike. With short, playful chainstays and a wide range of adjustments, it’s at home on technical climbs, powering through the rough stuff, and popping off every trail feature you lay eyes on. Grease ports in key pivot locations make for a stiffer, lighter, and lower-maintenance bike, and the Smoothwall carbon frame on Thunderbolt 799 MSL is a trim 2350g.
NEW FOR 2016: the ultra-stiff alloy frame now features our RIDE-9 adjustment system.
SMOOTHWALL™ carbon uses one of the world’s most sophisticated carbon processes to deliver industry leading stiffness-to-weight, ride quality, and durability. We eliminate excess resin and fibers by using rigid internal molds instead of traditional air bladders. We then utilize different types of carbon in specific frame areas to maximize stiffness and impact resistance while minimizing overall weight.
SMOOTHLINK™ suspension stays supple yet supportive through a wider range of gears than conventional single pivot or other four-bar suspension configurations. This patented system reduces both pedal-bob and bottom-outs, while allowing us to fine tune variables like braking and climbing traction across a wide range of intended uses.
Every riding style demands a different set of design principles. Whether we’re creating an XC-race weapon or an all mountain adventure machine, Ride Tuned Concept (RTC™) ensures that key variables like wheel size, suspension travel, and geometry work together to optimize ride quality
ABC™ Pivots are lighter, stiffer, and require less maintenance than conventional bearing pivots. Like our BC2™ pivots, they rotate on hardened alloy inserts that bottom out to reduce stiction and binding. However, by using an angled bushing surface they increase their relative contact area, optimizing them for compact locations like chainstay pivots.
Not all aluminum tubing is created equal. FORM™ provides the superior ride quality we are known for. Each FORM™ tube that we create is engineered for its specific purpose within the frame, ensuring optimized strength, weight, and ride quality.
FORM™ tubesets utilize premium materials to meet our strict requirements.
Our patent-pending PIPELOCK™ pivot uses a hard-anodized collet that expands radially to create the widest and most rigid pivot stance possible. Rather than relying on lateral compression for stiffness like traditional main pivot designs, our patent-pending PIPELOCK™ pivot uses a military grade, hard-anodized collet that expands radially to create the widest—and therefore most rigid—pivot stance possible. Using PIPELOCK™ allows us to cut our main pivot weight while significantly increasing lateral stiffness. PIPELOCK™ pivots also feature grease ports for effortless maintenance.
Bushing Concept 2 (BC2™) Pivots are the oversized next generation of our groundbreaking ABC™ system. Lighter and stiffer than conventional bearing pivots, our Bushing Concept 2 (BC2™) Pivots are the oversized next generation of our groundbreaking ABC™ system. Unlike other bushings, our patented system uses a hardened alloy insert that bottoms out to control the contact of the bushing surfaces, reducing the preload that causes stiction and binding. BC2™ Pivots also feature grease ports for effortless maintenance.
RIDE-9™ enables riders to choose one of 9 different geometry and suspension configurations to suit their riding style, terrain, and weight.