Fork offset is a favorite subject among armchair engineers and forum jockeys. There are endless theories out there, but when they get applied in the real world, it’s often just to maintain the status quo. But the status quo is not Transition’s forte.
Any discussion about offset has to start with trail. Trail is the distance between the point at which the front tire touches the ground and the point where an imaginary line extending through the steering axis intersects the ground. More trail leads to more stable steering at high speed but more sluggish steering at slow speed.
Conversely, less trail offers more twitchy steering at high speed but more responsiveness at slow speed. All other variables being equal, a slacker head angle gives you more trail, and a steeper head angle gives you less. A big wheel or a small wheel have the same effect, respectively.
The often misunderstood third variable in this equation is fork offset. Several brands build in more offset on their bigger-wheel forks to mitigate the sluggish steering that we were once so paranoid about. But now we’re seeing 29ers with head angles that seemed ludicrous in their early days, and some pretty amazing bikes have resulted. Maybe big-wheel offset deserves a second look.
Transition is giving it that second look. After years of experimenting, they’ve come up with the Sentinel, a long travel 29er built around a concept they call Speed Balanced Geometry or SBG, in the parlance of our times.
Transition recognizes that there’s a limit to how slack our head angles can reasonably get. The front wheel gets too far out in front of us and there’s less and less weight helping it dig into the dirt. They claim their new machine and its yet-undisclosed fork offset will change how we think about today’s longer/slacker geometry trends. We’ll be patiently waiting to get our hands on a test bike to give you our take on the concept.