A few years ago, I wrote a story for a Bicycling print issue titled “Mountain Bike Seat Angles Are Broken”. It struck a nerve because it highlighted something mountain bikers have been working around for years. There is no “right” saddle position and therefore seat tube angle. It depends on where you ride and how you ride. Same bike, same setup, yet a position that feels perfect for one rider in one region can feel completely off somewhere else. You end up shifting on the saddle, slamming the seat all the way forward on the rails or all the way back, trying to make one position work for everything, even though it never really does.
Pivot’s new Shuttle LT takes a swing at that problem in a way that’s surprisingly simple and, more importantly, useful. If you’ve ever fiddled with saddle position, questioned a geometry chart, or skipped a bike because a number didn’t look right, this is worth your attention.
Pivot calls the feature Slacky McSteepTube. Which is… a name. You can almost hear the product meeting where someone said it out loud, everyone laughed, and then somehow it stuck.
Seat tube angle has always been situational. In my earlier story, the point was simple. The “right” saddle position, and the seat tube angle that enables it, changes with terrain, suspension travel, suspension setup, saddle height, steepness of the hill, and most of all, rider preference.
And yet, for the last decade-plus, we have acted like there was a magical number out there that could somehow cover all of that for all bikes. There isn’t.
Pivot ran into the consequences of that thinking in a very real way. On paper, its seat tube angles looked slightly on the slack side compared to the competition. “Anytime pretty much any Pivot bike… they’re always like, ‘oh, the seat tube angle is too slack,’” founder Chris Cocalis told me. And that perception, he said, was often enough to stop riders before they even considered purchasing a Pivot. Never mind how it actually fit or rode.
Cocalis said they saw the same pattern with chainstay length. Historically, Pivot favored shorter stays because, through ride testing, that’s what the product team preferred. But as longer, size-specific chainstays became the trend, Pivot’s shorter numbers started turning some riders away before a test ride ever happened.
So Pivot adapted and began offering longer and size-specific stays. Which worked, right up until it didn’t. Riders who liked the brand’s original feel started pushing back. “We actually fielded quite a few calls asking if they could buy the shorter rear triangle,” of the smaller frame sizes, Cocalis said.
Pivot was now facing the same conundrum with seat tube angles. Steeper seat tube angles were becoming more fashionable. Meanwhile, “we have shops that do fittings and stuff, and they’re like, ‘these bikes with the seat tubes getting so steep, we can’t fit people properly — we can’t get them in the right position,’” Cocalis said.
So Pivot had to figure out how to win both sides of the argument without turning riders off before they even walked through the showroom door.
The answer was Slacky McSteepTube. Give riders a range. Let them decide.
From the outside, Slacky McSteepTube looks almost too obvious. It is just an offset insert that fits into the squoval hole cut into the frame in place of the usual round seat tube. Flip the insert one way, and the virtual seat tube angle is 78 degrees. Flip it the other way, and you are at 76.5. That is it. No levers, no linkages, no QR code leading to a lengthy YouTube explainer video.
Slacky McSteepTube’s steeper position allows the rider to get further forward in the frame and more on top of or in front of the bottom bracket center. This is often preferred by riders who tackle steeper, sustained climbs like fire roads.
The slacker position is the one many riders prefer when the terrain features more diverse pedaling situations, shallower grades, and rolling terrain where they are seated and pedaling for long stretches.
In doing so, Pivot is trying to thread a tricky needle. Riders who want a fashionably steep seat tube angle get exactly that. Riders and fitters who find those same numbers a bit much get an option that feels more natural. No one has to compromise before they even ride the bike.
“If they think they need a steeper seat angle, they’ve got a steeper seat angle,” Cocalis said. If they do not, they can flip it.
Notably, SMST changes the virtual seat tube angle by 1.5 degrees while leaving other factors, such as kinematics, bottom bracket height, and head tube angle, unchanged (or independently adjustable).
Slacky McSteepTube follows the same philosophy as the adjustable chainstay length, high- and low-flip chips, adjustable shock progression, mixed-wheel-size compatibility, and the other ways brands offer riders to tune a bike’s personality.
The idea behind all of them is the same: The brand doesn’t dictate; the rider decides.
There is a cost to these adjustments. Proprietary parts that need to be tracked down for repair or replacement. Potential new spots for frames to creak or break. And, of course, adjustable parts add weight and complexity.
On a lightweight cross-country bike, such trade-offs would be hard to justify. On a long-travel e-mountain bike with a motor and an 800Wh battery like the Shuttle LT, it barely registers. What the rider gains in personalization is worth far more than a few grams.
And importantly, Pivot’s system is not a science project. “Your ability to slide that thing out and flip it is just super quick,” Cocalis said.
Does this solve seat tube angles? No. And honestly, that is kind of the point. There is nothing to solve. There is only getting closer to what feels right for you, on the trails you ride most.
What Pivot has done is acknowledge that reality and give riders a way to deal with it. After years of arguing over half-degree increments, that feels like a step in the right direction.
A gear editor for his entire career, Matt’s journey to becoming a leading cycling tech journalist started in 1995, and he’s been at it ever since; likely riding more cycling equipment than anyone on the planet along the way. Previous to his time with BicyclingMatt worked in bike shops as a service manager, mechanic, and sales person. Based in Durango, Colorado, he enjoys riding and testing any and all kinds of bikes, so you’re just as likely to see him on a road bike dressed in Lycra at a Tuesday night worlds ride as you are to find him dressed in a full face helmet and pads riding a bike park on an enduro bike. He doesn’t race often, but he’s game for anything; having entered road races, criteriums, trials competitions, dual slalom, downhill races, enduros, stage races, short track, time trials, and gran fondos. Next up on his to-do list: a multi day bikepacking trip, and an e-bike race.