Issue #036, Review - December 21, 2018

Rocky Mountain Thunderbolt Carbon 90 BC Edition Review

The Rocky Mountain Thunderbolt BC Edition is guaranteed to put a smile on your face: it was by far the most agile bike in this group test. It flits from side to side faster than a rabbit on cocaine, but that means it will also test its rider’s skills.

For an overview of the test fleet head to the group test: The best trail bike you can buy

**Rocky Mountain** Thunderbolt Carbon 90 BC Edition | 140/140 mm (f/r) | 12.56 kg | € 6,199

The “BC Edition” tag on Rocky Mountain’s range of products has always meant longer travel suspension and harder hitting componentry, intended for a better time on the descents. The Thunderbolt is no exception. With 140 mm at the front and rear, the BC Edition has 10 mm more travel than the regular versions. The travel is provided by FOX Performance Elite suspension with a 36 mm fork, which uses the same interior as the Factory model but without the Kashima coating. The difference is completely negligible on the trail. The Thunderbolt also features Rocky Mountain’s own Ride9 system for adjusting geometry and kinematics. The bike’s spec is rounded off by SRAM Guide RS brakes with small 180 mm rotors, a SRAM X01 drivetrain and lightweight Stan’s Arch MK 3 rims with DT Swiss 350 hubs. A nice detail is the chain guide developed by Rocky Mountain, which gets bolted directly onto the chainstays. At 12.56 kg, the Thunderbolt is the second lightest bike in the test field.

The Thunderbolt is a good choice when you don’t need to go fast to have fun.

The Rocky Mountain Thunderbolt Carbon 90 BC Edition in detail

Fork FOX 36 FLOAT Performance Elite140 mm
Schock FOX FLOAT DPS EVOL Performance Elite 140 mm
Brakes SRAM Guide RS 180/180 mm
Drivetrain SRAM GX Eagle
Seatpost FOX Transfer Performance 150 mm
Stem Rocky Mountain 50 mm
Handlebar Race Face Turbine R 780 mm
Naben/Felgen DT Swiss 350/Stan’s Arch MK 3
Tires MAXXIS Minion DHF/DHR II
Weight 12.56 kg
Price € 6,199

**Reliable**
Rocky Mountain’s specially developed Spirit Guide chain guide does its job reliably and looks very nice doing so.

**Invisible**
Rocky Mountain skilfully conceals the pivot points, making the bike look very clean.

**Matching**
The decals on the handlebars are perfectly matched to the colour of the frame, just like the lettering on the fork and the wheels. The Thunderbolt is stylish down to the last detail!

**Very good**
The FOX 36 Performance Elite Fit4 has the same inner workings as the Factory version, only without the Kashima coating. The difference is hardly noticeable on the trail.

Geometry of the Rocky Mountain Thunderbolt Carbon 90 BC Edition

Size	XS	S	M	L	XL
Seat tube	356 mm	394 mm	432 mm	471 mm	509 mm
Top tube	548 mm	578 mm	603 mm	628 mm	658 mm
Head tube	100 mm	110 mm	120 mm	130 mm	145 mm
Head angle	65.9°	65.9°	65.9°	65.9°	65.9°
Seat angle	73.9°	73.9°	73.9°	73.9°	73.9°
Chainstay	426 mm	426 mm	426 mm	426 mm	426 mm
BB Drop	24 mm	24 mm	24 mm	24 mm	24 mm
Wheelbase	1104 mm	1136 mm	1162 mm	1189 mm	1221 mm
Reach	380 mm	408 mm	430 mm	453 mm	479 mm
Stack	583 mm	593 mm	602 mm	611 mm	626 mm

**Helmet** POC Tectal Race | **Glasses** Oakley Jawbreaker | **Jersey** iXS VIBE 8.1 | **Shorts** iXS ASPER SHORTS | **Shoes** ION Rascal

The Rocky Mountain Thunderbolt Carbon 90 BC Edition on the trail

Before taking a seat on the 27.5″ bike, it is worth pushing the saddle forward on its rails. Otherwise, the very short chainstays and the rather slack seat tube angle will quickly make you feel like you’re sitting too far above the rear wheel on steep climbs. It is generally worth reaching for the climb switch on the shock as the rear end tends to sag a little too much when going up steep bits. The Thunderbolt isn’t a super efficient climber despite its low weight, though it scores with plenty of traction in technical sections. Going downhill, the suspension of the Thunderbolt is very sensitive and plush, making for a comfortable ride. However, it offers little mid-stroke support over lips on the trail and through rollers, absorbing your input when you try to pump it, though this is compensated by the geometry, which is all for having fun. The super short rear end and the moderate reach make the Thunderbolt corner like nothing else. The faster and tighter the switchbacks are, the more the Thunderbolt shines. Flick out the rear wheel? Easy. Manual? It almost does it by itself! It even masters steep, technical descents with ease. But as soon as the trail picks up speed, you’ll have to stay vigilant, because at higher speeds the Thunderbolt demands a strong guiding hand – so don’t even try to keep up with your buddies.

Conclusion

If what you’re looking for is a trail bike with super agile handling and lots of comfort, the Rocky Mountain Thunderbolt BC Edition is the one for you. On climbs and high-speed descents, however, the bike prefers to take it easy.

Tops

very playful
beautiful frame
comfortable suspension

Flops

The rear linkage lacks support
nervous at speed
small brake rotors

Uphill

Downhill

Stability

Agility

Value for money

More info at: bikes.com