A group of engineering students from California Polytechnic State University have developed, built and tested a headset which can adjust a bike's head angle in under twenty seconds, without tools
. The product is the result of a senior engineering project by Ben Harper, Josh Martin, Dylan Prins and Glenn Petersen of Cal Poly Bicycle Builders, whose work we've reported on before
The headset offers three positions: neutral, steeper and slacker. It changes the effective head angle of the bike by +/- 2-degrees relative to the mainframe. However, because the head tube of the bike drops as the fork gets slacker, so the angle of the frame changes, the overall change in head angle is around 1.5 to 1.6-degrees either side of stock, depending on the length of the frame, fork and head tube.
While angle-changing headsets are nothing new, existing designs require a long while in a workshop plus specialist tools to swap out or change the orientation of the cups. That makes them a "set-and-forget" product. And while head angle can be adjusted with flip chips, these usually provide a tiny change in head angle and also alter the reach, bottom bracket height and seat angle, making them of limited use
. This headset can be adjusted on the trail-side with no tools in less than twenty seconds (the claimed average time is sixteen seconds). That means it could be adjusted to suit different trails, or changed between climbing and descending. The team suggest it could be rented out by bike shops to curious customers / bike nerds who want to feel the effect of different head angles with the most direct comparison possible.
The headset fits tapered steerer forks and uses ZS44- and ZS56-standard cups. The lower cup allows the bearing carrier to pivot as the head angle changes. The upper cup has three pairs of holes which attach to the bearing carrier with pins to securely lock the steering assembly into one of three positions. To avoid having to loosen the stem and preoad bolt before adjusting, headset preload is provided by a quick-release clamp and a conical spacer from One-Up Components. When the clamp is released, the headset has enough wiggle room to be adjusted, then the preload clamp is re-tightened once the pins are in position at the chosen setting. A Velcro strap ensures the pins stay securely in place.
The headset was designed using Finite Element Analysis, machined in-house and tested on a purpose-built test machine to four times the calculated maximum loading case. Only then was it tested out on the trails. After around 200 miles, the team say it performs just like any other headset while riding, and it never became difficult to adjust.
I asked Andrew Kean, Professor of Mechanical Engineering at Cal Poly and project sponsor, if they had any IP or patents on the product, and if they intended to commercialize it. "The way senior projects work at Cal Poly is the IP stays with the project sponsor (me)," he said. "I left it up to the students to decide if they wanted to maintain any IP or secrecy, and they all declined. If they had wanted to commercialize the headset, I would have supported them. But I think they were just happy to have a successful school project and then move on with their lives. I would love if others learn about the project and maybe improve the project on their own. In its current form, it would be great for a demo bike where a shop could allow a consumer to try out different head tube angles easily on the trail. It would need to be refined before it could be commercially successful for consumer sales."