Dangerholm’s sub-10 kg Scott ‘Hyper’ Spark is a concept MTB brought to life

There’s custom, and then there’s Dangerholm custom

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Most people, when putting together what they’d consider to be their dream bike, might be content to go with a nice paint job, some flagship components and wheels (with perhaps one or two over-the-top selections), and call it good. And rightfully so – any bike built with a collection of the finest off-the-shelf bits would likely be an awfully fine machine. 

Gustav Gullholm is not most people. 

A full-time shop mechanic by day, Gullholm is better known by his Instagram handle, Dangerholm. His latest project is a wildly customized Scott Spark. The starkly monochrome paint job is undeniably striking, and as you’d expect from a bike where virtually no expense was spared (and especially when starting out with a chassis that weighs so little already) it’s remarkably light. In its most feathery configuration (which includes a one-piece carbon fiber saddle and seatpost custom made by Slovenian company Berk), it’s a staggering 9.78 kg (21.56 lb). With a substantially heavier 170 mm-travel RockShox Reverb AXS dropper seatpost and foam tire inserts, it’s still a silly-light 10.80 kg (23.81 lb) — and that’s with pedals, mind you.

Among the boutique parts used are Syncros Silverton SL one-piece molded carbon fiber wheels, a SRAM Eagle AXS wireless electronic drivetrain (augmented with a Garbaruk cassette and chainring, a CeramicSpeed OSPW pulley cage system, and CeramicSpeed UFO chain), Fox Live Valve active electronic suspension, and a Syncros one-piece carbon fiber cockpit. 

However, true weight weenies will undoubtedly have had the thought already that while a sub-10 kg full-suspension is light, it’s not that light. But writing this off as just another pretty and expensive bike would be wildly discounting the amount of work that’s gone into it. 

Just like modern high-end road bikes, all of the control lines are almost completely hidden away — including inside the steerer tube, handlebar, and stem. Unused holes were patched over, while other holes were added (and appropriately reinforced) in places like the underside of the handlebar and the front of the steerer tube (inline with the stem extension). Custom cable guides were made for the back of the fork crown and lower legs, and in addition to being particularly lacking in grams, one of the reasons Gullholm went with the rarely seen Trickstuff Piccola Carbon brakes is because the hoses use banjo fittings at the levers that are ideally suited for internal routing.

To help protect the internally routed lines from damage during a crash, there’s a fully bespoke steerer stop system similar to Trek’s KnockBlock design. 

“One of the biggest challenges was the steering stop to make sure the internally routed cables wouldn’t be damaged,” Gullholm said. “A handmade aluminium plate, with replaceable stop pin, was molded onto the frame just behind the head tube. It actually goes all the way around the steerer/head tube, all wrapped in carbon. Behind the handmade cover sits the hardware that clamps onto the steerer tube, effectively stopping the bars from turning too much.”

The shifting, suspension, and dropper seatpost are all electronically actuated, and the controls (and battery) are fully integrated into the handlebar. Instead of the stock SRAM AXS paddle, Gullholm has opted for a custom-built twister setup.

“The controllers for the AXS derailleur and dropper posts are Zirbel Twister WE01,” he explained. “You can say it’s a hybrid between a trigger and a Grip Shift. A shift ring with a trigger rotates around the handlebars, with magnets inside of springs. You have one click in each direction; so for example, to shift to a lower gear you press down and to a higher you press up with the back of your thumb. You can also press and hold to do multiple shifts. The cables from the Zirbel Twisters normally connect to a SRAM AXS BlipBox but here they have been soldered onto the actual circuit boards of the AXS triggers. The cables run under the grips and all electronics are hidden inside the handlebars.”

Obsessive? You betcha.

A burning need

One might rightfully wonder what would motivate someone to go to such lengths to build something like this. However, my guess is that many veteran shop mechanics won’t need much of an explanation. You do this sort of thing because you can.

“I’ve always loved bikes since I was a little kid,” Gullholm said. “Of course, I enjoy other things, too, but bikes have always been my main hobby, training tool, and passion. When I was young, I wanted to become an industrial designer. I especially dreamed of working with car design. Life chose a different path but now with all these projects I come up with all these ideas and do my best to make them reality, so it feels a bit like I’m living a version of that dream.

“The Hyper Spark project had two main goals: try and build the fastest and best riding XC/XCM mountain bike possible but also [make] it the cleanest-looking yet with internally routed cables,” Gullholm said. “Being inspired by modern road bikes and hypercars, I set out to bring the same sleek and clean look to a full suspension mountain bike. While being such a unique and custom build, I really wanted to give it a stock look, as in that everything had to look factory-made or even better. Most of it was very much made in a small town garage, but it had to look as perfect as possible and look like something coming out of an R&D or design department with resources I can only dream of.”

Earlier Dangerholm builds were fully self-funded, but Gullholm thankfully enjoys a pretty good level of support these days. Remember that his day job is working in a bike shop, and even in Norway, shop mechanics aren’t exactly known to be dripping with cash.

“This is probably one of the most expensive mountain bikes in the world. And no, I haven’t counted so that I can give you an exact number.”

Given the cost and time invested in this thing, you might expect that it might just hang on a wall afterward to be admired. But nope, Gullholm has every intention of riding it — once the snow melts, of course.

“When you put so many work hours into something, it becomes kind of personal and more than just a bike,” he said. “Ideally, I would want to keep all of them, and end up with a crazy collection like some car people. But in reality I have some expenses with all the builds, and I have to sell a couple of the old ones that I spent a ton of money on to fund future projects and other things in life. Currently I have eight mountain bikes, with seven of them being top-of-the-line or even better. And some of them, like this Hyper Spark, I will never ever sell.

“After spending two years and what felt like endless hours on building a bike, you can almost get nervous about riding it. But I’m just so happy with how it turned out, and know it will be an incredible bike to ride, that I just can’t wait for spring. After all, it’s not a museum piece, but truly built for fun, training and racing.”

Build specs:

Frame: Scott Spark RC SL, size L, Fox LiveValve rear shock, 100 mm travel, custom steering stop, Extralite Blacklock rear thru-axle, Tune Würger Skyline seatpost clamp
Fork: Fox 34 SC Factory LiveValve, 120 mm travel, custom sensor/cable routing/steerer tube
Headset: CeramicSpeed bearings with custom steering stop and headset cover
Handlebars: Syncros Fraser iC SL, 90×730 mm, custom cable routing and carbon reinforcements
Grips: Syncros foam
Seatpost: RockShox Reverb AXS, 170 mm drop, Zirbel Twister WE01 custom controller
Seat: Syncros Belcarra R SL
Alternate seatpost/saddle combo #2: One-piece Berk combo with Schmolke Carbon TLO post, rails for flex, white, 183 g
Alternate seatpost/saddle combo #3: One-piece Berk combo, no rails, black, 133 g
Brakes: Trickstuff Piccola Carbon, special couplings for internal routing, Trickstuff Dächle UL 160 mm rotors, Bike Ahead Composites The Fixer adapters
Derailleur: SRAM XX1 Eagle AXS with CeramicSpeed OSPW system
Shifter: Zirbel Twister WE01 custom controller
Chain: CeramicSpeed UFO
Cassette: Garbaruk 12-speed 10-50T
Crankset: Tune BlackFoot with Garbaruk 40T chainring
Bottom bracket: CeramicSpeed
Pedals: Xpedo M-Force 8Ti
Wheels: Syncros Silverton SL full carbon, CeramicSpeed bearings
Tires: Maxxis Rekon Race EXO, 29×2.35”, with CushCore XC foam inserts
Sealant: Syncros Tubeless Sealant

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