Engineering Students Build Tool-Free Adjustable Head Angle Headset

Jun 30, 2021
by Seb Stott  

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.

A structural prototype without the Vecro strap or QR preload mechanism.

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."

If it took 20 seconds to adjust your head angle, would you?




152 Comments

  • 173 2
 What a time to be alive
  • 87 115
flag jaroh24 (Jun 30, 2021 at 13:06) (Below Threshold)
 What an obtuse comment
  • 47 0
 @jaroh24: you're scalene for a wailing
  • 18 1
 @jaroh24: You're probably right.
  • 31 0
 @jaroh24: Aw, you guys are being so acute!
  • 19 0
 @jaroh24: depends to what degree you care about the performance of your bike
  • 19 0
 It's an early prototype though, so we might all need to adjust our expectations
  • 11 0
 @jaroh24: he's just radian about how cool of a product this is
  • 18 1
 @jaroh24: I thought your comment was clever
  • 24 0
 I think everyone needs to cut these students some slack
  • 2 1
 Amazing comment!
  • 9 0
 @chickennuggetsaregreat: not to go off on a tangent but this is so classic Cal Poly - ie brilliant!!!
  • 4 0
 @justanotherusername: Yes, the VP Varial headset was a motivation for this project. The design discussed here has many advantages over the Varial, but the overall purpose is the same.
  • 5 0
 @shortsguy1: the tool part of the Varial was kind of a hassle... you guys did a good job i think... and i think the pins make a lot of sense... it is not necessary to have infinite adjustment...
  • 5 0
 It’s a sine of the times.
  • 2 0
 @kiwi-in-ns: I’d cosine that.
  • 154 3
 “Set and forget my own. Mess with my buddy’s when he’s not looking.”
  • 36 1
 Yeah, that is what my buddy did to me. Every ride with him my gears skipped and he kept telling me that Shimano makes bad gears. Only after I left the country did I realised that he had fiddled with my gears before every ride for years. Dedication.
  • 4 45
flag SterlingArcher (Jun 30, 2021 at 16:08) (Below Threshold)
 @freehound: we all turn barrel adjusters on n00b bikes when they aren’t looking. Everyone knows this
  • 3 0
 @nvranka: it’s a joke people get over it
  • 1 1
 @SterlingArcher: My bike is like my plate of food. Touch either and it's gonna be a real bad time, really quickly for you.
  • 55 0
 I'd probably over tighten and strip it
  • 2 0
 Or under-tighten it and die.
  • 47 0
 I can see this being good to play around with the head angle, to see what you like. Then when you decide, buy a bike/headset with a fixed angle.
  • 10 0
 agree - that's basically what they're saying. Borrow/rent one from the shop, put it on a bike you're familiar with, learn what works and then shop accordingly.
  • 2 1
 yeah, I think the bike company (or very crafty bike shop)
that creates a production version of a "mule" bike
which allows a shop to replicate the travel and angles of 3-4 different bikes
might have an edge on the competition.
This headset would fit right in on a project like that.
  • 4 1
 I generally agree but if you have one bike to rule them all putting it at 65 for normal trail riding, then down to 63.5 for bike park riding seems like the way I’d go. Luckily the Stumpy Evo does this without the big apparatus this thing has. Sweet project though!
  • 1 0
 If this used a single lever to adjust similar to a dropper post or lockout on a shock we would use this on every climb and descent. In its current form it is only a little more complicated to use than a QR seatpost and we adjusted those for every climb and descent for many years.
  • 40 0
 A+ on the design and the vid. I'd prefer if more product launch vids looked like this rather than some blockbuster anime short film.
  • 40 0
 Nicely done gentlemen. I hope you guys got a solid grade on this project. A+ from Professor Comments Section.
  • 35 0
 No one is going to argue that these engineers are slackers.
  • 13 0
 If they decide to commercialize this, I hope the price isn’t too steep
  • 23 0
 Let's see this puppy running off a motor controlled by GPS, so that when the system glitches, your head angle steepens at the same time your suspension locks and dropper extends as you drop into a nice steep chute. I've ridden bikes from the 80s, bring it on
  • 2 0
 In 2006ish Commencal had a head tube with an eccentric insert. In order to change the head angle you only needed to loosen two bolts, spin the insert 180°, and tighten the bolts. If I was going to have an adjustable HA, I think I'd want it to work something like that. We (should) all carry tools anyway. With that said, I don't feel a need to change my HA because it means relearning how the bike handles every time. And a slack HA doesn't actually seem to equal poor climbing, as we all used to believe.
  • 2 0
 @AndrewHornor: Mongoose made a DH bike in the 1990s that had a threaded head tube within a head tube and you could adjust the head angle easily.

Mongoose NX 9.7, 1999.
  • 1 0
 @iamamodel: love the simplicity of that. Actually that looks pretty nice for 99 even if the styling hasn't aged well. What happened to Mongoose anyway?
  • 23 3
 To me the best way to optimize your head angle is to have fun not thinking about it while you ride your bike. Pretty cool project though.
  • 7 0
 Seems useful for reviewers though!

Imagine when they say "would be nice to have it just a bit slacker/steeper" they could actually confirm if that is what they want or if there is something else they don't like.

For the rest of us, I'm not sure.
  • 10 0
 It's moments like these where I'm just sat on my ass thinking "What the f*ck am I doing with my degree?"
  • 10 1
 Why settle for one degree when you can have two?
  • 9 0
 Imagine if your university degree were adjustable like head angles.

That’s correct, I studied something in between underwater basket weaving and rocket science.
  • 9 1
 “The headset offers three positions: neutral, steeper and slacker“

Give me a call when the slack, slacker and slackest version is available. (If Chris Porter hasn’t TM’d that already) Smile
  • 9 0
 Park bike vs DH vs epic adventure.... this is dope i would actually use it.
  • 6 0
 The project lead seems like a pretty stand-up guy in this case, but it is worth mentioning that these sorts of IP practices (that all unis that I'm aware of follow) are, IMO, rather unfair. So many really hard to solve problems were/are solved by impoverished students (not being able to earn while studying results in negative income) that usually get sweet fa in return apart from debt and usually a good dash stress and misery.

Not saying it's the case here.
  • 11 0
 There is an old piece of advice I heard a lot during my degree, if you have a great idea when you are here don't do anything with it until at least 2 years after you leave or it belongs to the university. I got around this issue by not having any good ideas... very smart.
  • 4 0
 I'm a grad of Cal Poly's ME program, and I think the difference between it and a lot of schools is Cal Poly doesn't own any IP. When a company comes in and sponsors a project, they get whatever comes out, but that's pretty much the same as being a working stiff. I totally agree that the system where schools take all the IP from student work is all too common and exploitative
  • 1 0
 @jtambo: Thanks for you perspective and input!
  • 8 2
 It should be noted that this is Cal Poly, San Luis Obispo (the best Cal Poly) as there is one in Pomona and they're possibly making a third out of Humboldt State University.
  • 3 3
 Thanks, I was looking for this info since Pinkbike didn't bother specifying which CalPoly school they were talking about. Also it should be noted that POMONA is the better engineering school, while SLO is the better school for learning how to raise cows.
  • 1 0
 @SeanC1: Sorry I didn't realize there were two of the same name. You can click on the link in the first sentence if you want to find out more about the team.
  • 3 0
 @SeanC1: sorry but wat. Not sure why we build the float and you provide the flowers then
  • 7 0
 Next step is to make it wireless……! Great idea guys.
  • 3 0
 I mean, it is!
  • 2 0
 This is neat - and could be even neater if they also figured out a way to subtly adjust fork length with it to compensate (so you don't end up dropping your bottom bracket when you go a wee bit slacker or vice versa). I could see this sort of thing being built by one of the outfits usually associated with clever solutions and good build quality (OneUp, Wheels Manufacturing, etc.).

While we're on the topic of head tubes and head sets - why do we still do Star Nuts? Argh...
  • 3 0
 u-Turn All Over again, So Easy To Do With a coil fork, I'm Surprised It's not used more
  • 2 3
 @allsk8sno: Because it was extremely unreliable.
  • 1 0
 @allsk8sno: DPA at least I say. But companies want you to buy three bikes instead. BB needed to be a tad higher though.
  • 1 0
 @jomacba: I don't remember it as unreliable, but it was a compromise since the short travel didn't change spring rate. Yield air version I do remember as unreliable. Bionicon may have had the better solution, but it was not paired with good suspension.
  • 3 0
 the bottom bearing sits in a conical socket, but the top one seems to just slide and remain parallel. How is the axis offset accounted for in the top bearing? is there a curvature profile on the upper assembly?
  • 11 0
 Yes, the top headset cup's top surface is curved to account for the axis offset you mentioned. Different headtube lengths result in different offsets, so we used a middle-of-the-road curvature
  • 1 0
 @benarper: awesome thanks for the response, very sick idea i would totally rock one on my enduro to swap between improvising a slope course or full on DH days.
  • 2 0
 Also, understand that riding Cuesta Ridge behind Cal Poly SLO is a steep pedal up and rough DH. For where they were testing I would be into switching up the HTA for each climb and DH. I think a better solution is one we have had for years, travel adjust forks. That way you get to adjust HTA, travel and LSC with a flick of a switch while riding. Cool eng project however.
  • 2 0
 I'd buy this in a heartbeat if the following issues was resolved:
The loose pins were replaced with some kind of spring-loaded pin solution, which means less chance of loosing pins and less steps to move position.
The preload system would be changed to something like a eccentric-concentric expanding solution which doesn't require a big QR lever, but can be solved with a smaller, locking solution.

I can see the solutions in my head, but it's hard to put into writing without drawing it out. Brilliant concept though.
  • 2 0
 Good work on the idea, execution and all. Congrats

Normally, we only need slack when turning down, and besides, with an upright headangle, it would be great to have less travel and harder suspension.

There are/were in the past bikes that could formshift with a button. Brands like Canyon, another german company that I don't recall that had an adapter above the shock and connected with the fork.

The way I see, is that complicated design although solving some problems, it creates others problems.

On the other hand, droppers are much more complex and today almost everyone wants it....
  • 1 0
 Creative and impressive. Nice work by the Cal Poly students. It to me is another level of the adjustable geometry direction (I think back to an older Santa Cruz Bullit I had where you could adjust the geometry via the rear shock pin and I thought way back then "wow, what will they think of next?")

I would look forward to seeing it be sleeker/more stylish but equally as functional. Great idea and great design/implementation.
  • 1 0
 This reminds me of when companies trying to invent one thing, hit the big time because of another thing. The guy who invented postit notes was failing at making super glue. I expect these guys will hit the big time when the big companies realise that, even with all those temporarily moving parts, the headset didn't creak..... witchcraft.
  • 1 0
 What we really need is a headset which is adjusted in real time during the ride by the smartphone! So that headset can be automatically adjusted to be slacker while going downhill, steeper on the uphill and something in the middle for the flats. It would work great with GPS controlled dropper post and wireless brakes!
  • 1 0
 Pretty dope, nice work guys! I think for the average person they'd only need a two-position adjustable h'set (neutral and a steeper or slacker adjustment), but props to these kids.
  • 2 0
 Great idea and nice video. Give it 5 to 10 years and this could be the dropper post of today. More refined, but the idea is sound. Hats off.
  • 1 0
 Just wanted to mention this. Almost seems like it got re-invented here. Looking at the modest success of the VP headset, it is probabably not much more than an engineering excercise by some students.
  • 3 0
 The most impressive thing here is the guy who hits jumps with 6 inches of steertube staring him in the sternum.
  • 3 0
 Nice. Can't wait to see it come to market.
  • 3 0
 Is it compatible w/dual crown?
  • 1 1
 don't see why it wouldn't be.
  • 1 0
 Based on the info it would as long as it has a taped steerer which is available on some but not all dual crowns.
  • 4 0
 That's pretty nifty!
  • 3 0
 A+ Grade. Great execution of the project!
  • 3 0
 I could see this being useful on a gravel or bike packing bike.
  • 1 2
 The set it and forget it crowd. Really? Have you actually been able to do this? Not everyone wants to spend thousands son a bike that it one or extreme or the other or just a bad compromise between the two.

Because remember droppers? Wasn’t such a bad idea.
  • 1 1
 Is changing angles going to save i6 seconds between trails or climb / decent?. No. Great tool for research but until it can be as quick as a dropper post. M ay be the next step? IDK
  • 10 0
 imagine youve got a 420min climb to a 69min decent. those 6-9 seconds might be the best spent foreplay youve ever done.
  • 2 0
 i see what you did here. you wanted talk bikes, ride and wrench at school. nice
  • 2 0
 Can't wait to see an electric dropper headset making it's way into the market.
  • 1 0
 It's only a matter of time before Scott hooks this up to their TwinLoc system to steepen the HA when reducing suspension travel of the bike. Makes sense?
  • 1 0
 Test it at Whistler for 2 months with a park rat having his way with it. If it can survive Whistler, it is a viable product.
  • 4 2
 The guy is going to smash his teeth out... cut that steerer tube bro
  • 3 0
 They needed a new fork with an uncut steerer tube. Probably sold the fork already and put the original one back on.
  • 3 2
 If your head angle is slacker than 65 degrees, happy days, go for a ride. If its steeper, time for a new bike Smile
  • 2 0
 Anything with velcro has my vote lol
  • 1 0
 This article is to show older people that youth are using their brains. Ther´s hope people
  • 1 0
 Sounds like that april fools joke from over a decade ago:
www.pinkbike.com/news/straitline-quickie-stem-2010.html
  • 2 0
 Ill wait until Scott makes one that's controlled by a lever.
  • 4 0
 It’ll be controlled by 4 cables and only work with their proprietary fork
  • 1 0
 @mtallman2: At least it'll be internally routed - for convenience.
  • 2 0
 Can we integrate it with the Fox heart rate technology?
  • 2 2
 Good work but I wish they had proofread the digital poster. "Gained insight into user perspective from a broader audience would also be gained."
  • 5 0
 These are engineering students. You're looking for a student with an English major.
  • 1 0
 Good news for me! I live in San Luis, so I'm going to go over there and get one.
  • 1 0
 am I the only one that doesn't know if he could trust something from some guys that put their handle bars on backwards? lol
  • 1 0
 Now add a sensor under the saddle and make it change the angle when the dropper goes down
  • 1 0
 Can someone please please please make an angle-set headset compatible with IS42 (specialized) upper bearings? Please....
  • 1 0
 Rich kids designing crap to justify their college experience to their parents. LOL!
  • 1 0
 I love seeing this kind of thing coming out of engineering courses. Bloody good idea and presentation.
  • 1 0
 Love it. looks quite light as well!
  • 1 0
 specialized should hire those folks
  • 1 0
 Interesting. Who's got the steepest head tube angle? 71.4 here Big Grin
  • 1 0
 Isn't set & forget the same as try & pick one?
  • 1 0
 Great Job guys, impressive, make sure you patent this!
  • 1 0
 I'll wait for the +/- 2.09 boost degree version
  • 1 0
 This is awesome. I'd buy one right now.
  • 1 0
 Velcro… -scratching chin- hmmm
  • 1 0
 iam waiting for a wireless version of this
  • 1 0
 Handy thing for company’s trying new prototype frames.
  • 1 0
 Great work team, love the video too!
  • 1 0
 jomacba Dont u now nuthin its Umerica Dang forinurs gitcher werds rite boy
  • 1 0
 I just strap a headset press to my face
  • 1 0
 Bike industry about to send death threats to this boys
  • 1 0
 A new standard?
  • 1 0
 Nice work boys!
  • 1 0
 Oh Cal Poly!
  • 2 2
 Pretty cool college project but kinda worthless
  • 1 2
 Headset cups? What are those? I haven't had a bike with headset cups in 3 years.
  • 1 0
 Well done gentlemen.
  • 4 6
 Good Job Gent's! Real American ingenuity!
  • 7 14
flag jomacba (Jun 30, 2021 at 13:47) (Below Threshold)
 Dang ol' boys, workin' hard to provide good ol' merican gizmos and such to good ol' merican people. Before you know it, these good ol' boys be providin jerbs to the rest of you mericans!... Merica!
  • 2 1
 @jomacba: haha i bet your hands were shaking and you broke into a cold sweat typing that out
  • 2 2
 @quesoquesoqueso: You better believe it, but I'm not sure if it was cold sweats, or because it was 41°c outside... Or as you Yanks would say 106°. Don't ask how tall I am in centimeters though.
  • 2 0
 @jomacba: you betcha
  • 1 1
 @quesoquesoqueso: Was that a dig at us Canadians? Your bein' a bit of a hoser eh!
  • 1 0
 @jomacba: I am soory my gallon of gas or 3.785L for you cost me $3.45 and you are paying 6 to 8 Loonies or 3 to 4 Toonies for it. YEA CANUKS!!!
  • 1 1
 @krumpdancer101: Oh that don’t bother me tho... I mostly take my dog sled wherever I go, or I take the poutine powered zamboni to go get myself a 2-4 and a bottle of pop.
On a serious note, people are seriously downvoting me? I’m quite clearly joking.
  • 1 0
 @jomacba: lol I was just messing with you. My wife is from Port Coquitlam so we always do the Canada versus America joking thing. Definitely didn’t down vote you though.
  • 2 0
 @krumpdancer101: oh I know you were for sure. I was actually enjoying the banter. I just noticed I was being downvoted, and kinda thinking to myself “for real?”.
  • 1 0
 @jomacba: hey we can continue?? Don’t let votes stop you lol. Here I will start..... Aahhmmm so your mama soooo fat, oh sorry wrong thread lol. I don’t know what’s better the fact poutine is basically the fried version of baked potato covered in gravy that is sold at Wendy’s or the cigarette boxes hidden in the deep dark cases in 7-11. I gave you a up vote
  • 1 0
 @krumpdancer101: Hahahaha, ahhh thanks buddy!! Your probably right on the poutine thing, bit at least we have things that aren't deep fried. That being said putting maple syrup on everything gets to be alot after a while, plus these Sorels are making my feet sweat in this heat!
  • 1 0
 @jomacba: hey sorry my feet were sweating also in my chuck Taylors so I had to go to my crystal clear lake and paddleboard and get drunk to beat the heat. Now where were we. Dude till you have tried a fried Oreo you have not succeeded in life. It might hurt on the way out but so nice on the way in.
  • 1 0
 @krumpdancer101: I literally laughed out loud from that one. Im gonna have to try that one actually. Might need more than a serviette to clean that one out of the chesterfield though. Probably best had after supper too.
  • 1 0
 @jomacba: Lol hey you could always get a colostomy bag so you never have to use the pooper again!!
  • 1 0
 @krumpdancer101: I dunno, that sounds pretty messy. Plus where would I put it when I ride? Not really into hip packs.
  • 1 0
 @jomacba: dude colostomy bags are the shit!!! The original fanny pack lol.
  • 1 0
 @krumpdancer101: Pun fully intended... u sound like you are speaking from experience!
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