2017 Tantrum Meltdown

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Reviewed by Brandon Turman // Action photos by Shawn Spomer

While hunting for new and exciting products among the thousands of booths at the Interbike tradeshow two years ago, I recall seeing a bright yellow bike roll by with a wild-looking suspension linkage. It was so different from the norm that it forced me to do a double-take. What on earth was I looking at, and why were there so many links? I chased down the bike's owner, Brian Berthold, to ask for more details. Though I'm well-versed in the mountain bike suspension realm, what Berthold proceeded to claim the bike performed like on trail puzzled me. Like many before him, he essentially claimed it pedaled like a hardtail and descended like a proper all-mountain bike. Could the addition of one link really make that much of a difference, or was this just more marketing hype?

Just weeks ago Berthold went live with a crowd-funded Kickstarter campaign to bring his creation to life on a larger scale. Having reached his funding goal ahead of time, Tantrum Cycles and the "Missing Link" suspension are very close to being a tangible reality for the public. Today we look at the tech behind the bike and take a prototype for a spin to see how it rides.

Highlights

• 6061 aluminum frame
• 27.5-inch wheels
• 160mm (6.3-inches) of rear wheel travel
• Missing Link suspension design
• Tapered headtube
• 73mm threaded bottom bracket shell with ISCG mounts
• 148mm Boost rear axle spacing with 12mm through axle
• Post mount rear brake with replaceable threaded inserts
• Modular design allows multiple configurations (27.5, 29, and 27.5/29 combinations possible)
• Offered in three sizes: Short, Medium, Long
• Frame weight with X Fusion shock (claimed, size Medium): 7.5-pounds (3.4kg) // Without shock: 6.9-pounds (3.2kg)
• Frame MSRP: $2,600 USD (estimate with X Fusion shock)

Missing Link Suspension

You may remember Berthold from his invention of the Kona Magic Link a handful of years ago. What makes Tantrum's bikes most unique is the suspension design, which use what is referred to as the "Missing Link" connecting the chainstay to the shock.

In Berthold's words, "The Missing Link suspension is just that. It is the link that has been missing between motorcycle suspension and bicycle suspension. It connects the primal need for bump absorption with the advanced evolution of pedaling and climbing performance. With no electronics, levers, or need for rider interaction other than riding the bike.

Since the advent of suspension for mountain bikes, the traditional goals of plush suspension action for comfort, traction and control has been at odds with the desire to minimize rider induced suspension action due to pedaling and weight transfer due to climbing. Until now, it has never been accomplished."

This Tantrum video illustrates how pedaling and bump forces impact the suspension:

Due to the lower link configuration, it's claimed to be far stiffer under pedaling than the vast majority of trail and all-mountain bikes. Yet when it hits a bump, it’s allowed to open up, giving the bike some traction and bump absorption. The leverage curve has a falling rate from sag to 50%, and from 50% on it becomes more progressive.

The impact this system has isn't limited to the suspension feel, but also influences the bike's geometry as you climb: "The Missing Link is able to fully extend the rear shock during steep climbs, while still maintaining full bump absorbing capabilities... Simply put, this puts the rider in a much better position on the bike, more over the pedals and handlebar, enabling more of the rider’s energy to go directly into pedaling."

Geometry

The Meltdown's numbers are up to date with what many consider to be modern enduro/all-mountain geometry, including relatively healthy reach measurements, a snappy chainstay length, low bottom bracket height and decent standover. With a 160mm travel fork, the Meltdown sports the following:

On The Trail

Tantrum met with me in Boulder City, Nevada to showcase the Meltdown on the rowdy, rocky, unrelenting terrain of the Bootleg Canyon trail network.

Setting the bike up and bouncing on the saddle, I was met with the suspension feel typical of a bike equipped with a low-volume air shock from a few of years ago - stiff off the top, a soft transition/mid-stroke, and a good deal of ramp right at the bottom. Given the improvement in shock and frame design over the past three to four years it wasn't the best first impression, but I kept an open mind and off we went. Parking lot tests never reveal the full picture...

Our pedal-powered climb to the top included a mix of fire road and semi-technical singletrack sections, and the rear shock was left in the softest compression setting. At a casual pace the bike neither wowed nor disappointed. On the gas, however, I was instantly surprised by just how quickly it responded to hard pedal inputs. Even though it has 160mm of travel, it stands up and accelerates with a gusto comparable to a good bike with 50-60mm less travel. Provided my cadence was smooth and consistent, the corresponding burst of uphill speed was nothing short of impressive. I actually found climbing fun during these sprint efforts. At no point did I notice any harsh pedal feedback while pedaling over bumps. Unlike a hardtail, the rear wheel stayed pretty well glued to the ground through the rough stuff.

Turning downhill, would the suspension action translate in a positive way? Bootleg's rough Boy Scout and Girl Scout trails served as the real proving grounds.

What I found is that the bike has a great ability to maintain speed, in large part thanks to its pedaling traits for those smooth sections of trail between features. In most instances you get the sense that you're on a lighter bike with a low perceived weight, though it felt a bit mushy when pressing into turns and pumping compressions. While coasting, outright suspension performance wasn't quite on par with current market leaders, lacking that supremely supple, capable, "I can do no wrong" feeling. It wasn't half-bad, however. It has a precise nature that allows you to change lines easily. Getting the front end up for manuals was also a little difficult, requiring a solid tug at the bars and weight transfer over the rear wheel.

As for big-hit performance... not bad. While I felt the bottom a handful of times running ~30% sag and it could use some added progression either in the leverage curve or shock, I felt controlled coming out of a few sizable features.

Changes For Production

The bike shown in this feature is a pre-production prototype, and will see the following changes before being delivered to riders. Each of the changes will be a benefit and help polish the overall package.

• The bike will use a cartridge bearing instead of DU bushing in the rocker/driven link pivot. This was the only pivot that didn’t have a bearing on the prototype, and the change should improve small bump compliance thanks to the reduction of friction.
• It moves to 12x148mm Boost rear dropouts, with optional 142mm versions available at an extra cost. This brings it up to the latest standard and improves wheel rigidity.
• One degree slacker headtube angle, down to 65-degrees.
• Chainstay length will decrease from the prototype's 445mm length to 429mm, furthering maneuverability, allowing the front end to come up a bit easier, and improving the bike's overall fun factor.
• Tire clearance will increase to allow for tires up to 27.5x3.2-inches.
• Front derailleur compatible
• Room for full size water bottle
• Threaded bottom bracket
• Internal derailleur and dropper post routing
• External brake line routing
• Expected production frame weight is 100-200 grams lighter
• Offered with an optional DVO Topaz rear shock
• The X Fusion shock tune sees a slight increase in high-speed compression and slightly smaller air can volume for a more progressive ramp up.

Models, Pricing and Availability

Four builds are available to suit a wide variety of budgets ranging from $2,600 to $6,900 USD. Builds can be upgraded to include the DVO Topaz rear shock for an extra $175, which is an upgrade we'd recommend for the best suspension performance. Frame and shock combos run $2,600 and are currently priced at $1,400 for early backers.

One aspect of Tantrum bikes that may interest riders are their modular design, which allows for five travel/wheel configurations by changing the dropouts, rocker arms, shock, and shock mount. On the trail we noted some minor play in the interchangeable dropout when rocking back and forth with the rear brake locked, though this may be addressed in production.

With the right parts, you can turn a standard Meltdown (27.5 x 160mm travel) into:

• Meltdown RACE: Slacker geometry, 180mm fork, 160mm rear travel, 27.5 front and rear
• Outburst: 140mm fork, 125mm rear travel, 29 front and rear
• Outburst RACE: Slacker geometry, 150mm fork, 125mm rear travel, 29 front and rear
• Outburst XC: Steeper geo, 125mm fork, 125mm rear travel, 29 front and rear
• Downburst: 150mm travel x 29 front, 165mm travel x 27.5 rear

Shown above is the Outburst, a 125mm travel 29er trail bike. Tantrum is also working on both a 150mm travel 29er and 125mm travel 27.5 variants that may be available in 2017.

Tantrum will offer direct-to-consumer availability in 2017, and the Kickstarter campaign is still active for those who'd like to get in on the action early.

What's The Bottom Line?

While our test ride was short and sweet, this bike reaffirmed that first impressions don't always carry over to the trail. The Tantrum Cycles Meltdown surprised me in a positive way. Berthold's many claims are over the top, but there is indeed promise in the unique Missing Link suspension design. The how and why are still a bit fuzzy, but I can confirm that this bike does indeed pedal incredibly well without sacrificing traction in the same manner that many other bikes do. Provided Tantrum is able to dial in the many minor but important details required of a solid bike, I see the company's lineup as viable contenders in the marketplace with good potential to improve their overall rating.

Visit www.tantrumcycles.com for more details.

About The Reviewer

Brandon Turman - Age: 30 // Years Riding MTB: 16 // Height: 5'10" (1.78m) // Weight: 175-pounds (79.4kg)

"I like to have fun, pop off the bonus lines on the sides of the trail, get aggressive when I feel in tune with a bike, and really mash on the pedals and open it up when pointed downhill." Formerly a Mechanical Engineer and Pro downhill racer, Brandon brings a unique perspective to the testing game as Vital MTB's resident product guy. He has on-trail familiarity with nearly every new innovation in our sport from the past 5-6 years and a really good feel for what’s what.