Pinkbike Poll - Adjustable Geometry
Whether or not user-adjustable adjustable frame geometry is a good or a bad thing can be answered with the mention of one name: Jan Karpiel. Karpiel's claim to fame is an almost infinitely adjustable frame that uses a series of eccentric cams at the shock locations and other points to allow users to tune the suspension's travel and rate, as well as set the bottom bracket height and to some degree, the bike's head angle. As a result, the famous Disco Volante and Armageddon could be custom-tuned to be either the best or worst handling bikes on a given day. In defense of Karpiel, those who have mastered their range of adjustment swear by them. It is safe to assume, however, that even above-average mountain bikers have a relatively limited understanding of suspension rate curves and frame geometry, and thus the probability of an experimental knob-twiddler arriving at the Karpiel's optimum setup is about 33 percent, spread equally between good, acceptable and bad.
![Karpiel Armageddon]()
Innovation, or an Answer to Uncertain Times?
Adjustable frame geometry is a recurring theme among mountain bike designers. Invariably, it becomes a popular concept during periods when the landscape of the mountain bike is in flux - when neither bike makers nor riders can accurately pinpoint what numbers will result in the perfect bike. At its heart, the concept is a hedge - a way for bike makers to assure old-school riders that they can buy a new bike with the traditional numbers they have grown to love, and still sell the bike to new-school riders who want more progressive geometry. Consider how many all-mountain/trail bikes came with 'chips' on the rocker or shock mounts three years ago that lowered the bottom bracket and slackened the head angle. Today all good AM/trail bikes have incorporated those desirable features and while the chips may or not be present on the latest designs, the low and slack concept has been incorporated and thus the need for the chip is questionable.
Angle Set to the Rescue
Most recently, mountain bike head angles became two to three degrees slacker across the board within a two-year period. That left a number of riders stuck with steeper-than-fashionable bikes. Those guys and bike-makers that either failed to respond or got caught out with existing designs mid-way through their production phases were saved by the Cane Creek AngleSet adjustable headset. During the transitional stage that ensued, the addition of an AngleSet, or one of its copies, offered old-school bike owners a chance to try slacker head angles - and it gave OEM bike designers some wiggle room to slacken their head angles enough to conform with the fashion and appear edgy, without actually being fashionable or on the cutting edge. The question arises, however, that once frame geometry has stabilized (as it nearly has at this point), is the addition of adjustable geometry a potential performance enhancement, or is it merely an invitation for users to ruin the performance of an otherwise sharp-performing bike?
![Curtis Keene s 12 Specialized Stumpjumper Carbon EVO]()
There Can Be Only One
Adjustable geometry teaches us that ultimately, there is only one adjustment that results in the optimum performance for any given chassis. Once that is found, the bike no longer needs adjustment features. Supporting that argument is the fact that bike designers who truly know their stuff, wrestle with very minor changes in frame numbers in order to enhance a bike's performance - one degree in the head angle, 1/4-inch at the bottom bracket height or 1/8-inch in the chainstay length are huge alterations to them. Modifying the head angle beyond a finite point also requires a corresponding change in the fork offset to optimize steering forces - a relationship that is largely ignored by Angle Set users. Once a bike is optimized, big changes in its geometry most often result in a small gain in one area of its handling at the expense of larger losses elsewhere across the board.
Can a Good Bike be Made Better?
Judging by the limited number of bike models that are consistently rated as the best performing bikes in the world, it can be argued that there are only a handful of bike designers who truly understand frame geometry and the relationship between suspension rate curves and ride quality. That said, a strong case can be made that once the bike industry has settled upon the correct balance of suspension and frame numbers to accommodate slacker head angles, adjustable headsets and frame geometry will no longer be necessary and ultimately, would be detrimental to the performance of the average bike. It's an easy sell, however, and marketing blingsters will no doubt fight hard to keep adjustable geometry integral to many bike designs, but time and again, history has shown that fewer adjustments are always better.
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Karpiel's forward-thinking Armageddon frame design had an eccentric system that allowed adjustable ride height (BB height), the shock's rate and travel, and head angle - in addition to a front-center adjustment. Karpiel promo photo
Innovation, or an Answer to Uncertain Times?
Adjustable frame geometry is a recurring theme among mountain bike designers. Invariably, it becomes a popular concept during periods when the landscape of the mountain bike is in flux - when neither bike makers nor riders can accurately pinpoint what numbers will result in the perfect bike. At its heart, the concept is a hedge - a way for bike makers to assure old-school riders that they can buy a new bike with the traditional numbers they have grown to love, and still sell the bike to new-school riders who want more progressive geometry. Consider how many all-mountain/trail bikes came with 'chips' on the rocker or shock mounts three years ago that lowered the bottom bracket and slackened the head angle. Today all good AM/trail bikes have incorporated those desirable features and while the chips may or not be present on the latest designs, the low and slack concept has been incorporated and thus the need for the chip is questionable.
<Deleted photo>
Angle Set to the Rescue
Most recently, mountain bike head angles became two to three degrees slacker across the board within a two-year period. That left a number of riders stuck with steeper-than-fashionable bikes. Those guys and bike-makers that either failed to respond or got caught out with existing designs mid-way through their production phases were saved by the Cane Creek AngleSet adjustable headset. During the transitional stage that ensued, the addition of an AngleSet, or one of its copies, offered old-school bike owners a chance to try slacker head angles - and it gave OEM bike designers some wiggle room to slacken their head angles enough to conform with the fashion and appear edgy, without actually being fashionable or on the cutting edge. The question arises, however, that once frame geometry has stabilized (as it nearly has at this point), is the addition of adjustable geometry a potential performance enhancement, or is it merely an invitation for users to ruin the performance of an otherwise sharp-performing bike?
Initially, Specialized used adjustable flip-flop chips in its trailbike suspensions to give riders the option to sign on to its evolving frame geometry. When their low BB and slacker steering geometry was accepted, Specialized dropped the feature. The Stumpjumper Carbon Evo is one of the most balanced handling trailbikes made.
There Can Be Only One
Adjustable geometry teaches us that ultimately, there is only one adjustment that results in the optimum performance for any given chassis. Once that is found, the bike no longer needs adjustment features. Supporting that argument is the fact that bike designers who truly know their stuff, wrestle with very minor changes in frame numbers in order to enhance a bike's performance - one degree in the head angle, 1/4-inch at the bottom bracket height or 1/8-inch in the chainstay length are huge alterations to them. Modifying the head angle beyond a finite point also requires a corresponding change in the fork offset to optimize steering forces - a relationship that is largely ignored by Angle Set users. Once a bike is optimized, big changes in its geometry most often result in a small gain in one area of its handling at the expense of larger losses elsewhere across the board.
Can a Good Bike be Made Better?
Judging by the limited number of bike models that are consistently rated as the best performing bikes in the world, it can be argued that there are only a handful of bike designers who truly understand frame geometry and the relationship between suspension rate curves and ride quality. That said, a strong case can be made that once the bike industry has settled upon the correct balance of suspension and frame numbers to accommodate slacker head angles, adjustable headsets and frame geometry will no longer be necessary and ultimately, would be detrimental to the performance of the average bike. It's an easy sell, however, and marketing blingsters will no doubt fight hard to keep adjustable geometry integral to many bike designs, but time and again, history has shown that fewer adjustments are always better.
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also if you have only one bike.,. and you ride some street too.. it is nice if you have some simple on the fly adjustments..
peeps learn quite easily what works for them.. every bike build is different too.. may it be bar height or anything else for that matter..
a few simple adjustments on a frame are a plus+ in any case..
i would have liked to still have the 180mm option the mk1 legend did have and the mk2 doesnt..
if it doesnt hurt the durability of the frame.. or makes it look retarded.. i'd say.. yes.. give it adjustments..
I think Head angle adjustment is stupid for smaller bikes - if you are truly fast and want to keep 6" bike - get a 180 fork. If you want steeper HA then just get a shorter fork, thus the BB will also drop and compromise for lower stability. This is how it's always been done but ince 5 years people went - Oh but If I get a bigger fork the BB will raise! oh really? And if you lower it by design, where will that added travel go? Got a portal to a paralell universe under BB so you don't hit the ground at bottom out?
It's all about really dialing it in for the given situation. No one can deny that having adjustments for one situation then for another on the opposite side is the best case-scenario vs. having really one bike with a absolutely set in stone geo. Essentially you're getting almost 2 bikes in one in that sense.
The article says "shut you mouth youll get the bike we sell you!"
Never bothers to mention that slacker angles are a responce to market demand and not some breakthrough in handeling research
You DO adjust your head angle when you adjust your fork's travel. It's about 1 degree per inch of travel.
Not so much for a dirt jumper (or maybe a dh bike) because some things aren't really possible to safely adjust: top tube length/bb for dirt vs street, etc, but its an integral part of trail riding or in other words a bike that can do it all.
I think the best way to tailor your bike to your style is mostly through the parts you put on it, and how you set it up
One other point that we should all consider is the fact that some of us are "tuners". In other words, some people like to make some changes along the way to satisfy that hidden engineer inside. When I first bought my Intense M9 I put a "stock set-up" on the bike and it was great. However, after spending some time with Chris Kovarik (he sold me the bike) a few weeks later we made some major changes to the set-up. Based on the type of rider I aspire to be and the trails that I like at Whistler, we changed the entire "character" of the bike in less than 10 minutes! At the end of the day my enjoyment factor went up by a factor of 2 … isn't that what it is all about!!!
It is a fallacy that there is one "right" geometry, especially for Trail / AM type bikes. Some folks local trails are going to be much steeper / faster / slower / more technical / jumpier / downhilly / whatever than others. One geometry set just can't be best for all those differing terrains, so a manufacturer who wants to sell the same bike/frame to everybody makes the thing a load more versatile if it can be tweaked to suit differing styles of riding when the rider is initially setting it up.
It gives a good get out for buyers. It's scary enough buying a new bike / frame already... Get it home, ride it properly, gradually discover it feels slightly steep or high for you and if there's no possibility to adjust, where does that leave you? Giving riders the option to make tweaks (even just by ensuring compatibility w anglesets / offsets) has to be a good thing if you buy something that turns out to be not quite perfect for you at stock.
Not eveyone likes the same thing. Some folk like slacker / lower bikes, some prefer steeper. Give people some tuning and more people can make your suspension platform into the bike they want.
If you've got a chance, I totally recommend testing.
Gosh I'm confused. Sounds like somebody likes Cane Creek a lot.
I also think mtbers in general place too much emphasis on single aspects of bike geometry - usually head angle.
Nowhere in the article does it talk about how you want different geometries for different types of riding, sorta missed a big point there. Also never mentions that the best thing about an adjustable geometry all-mountain bike is that you
can change the angles for climbing and DH, such as with the Cannondale Claymore.
How does the author know geometries have stabilized and won't change anymore, does he have a crystal ball that predicts the future? No, he is just an amateur writer who makes stupid assumptions and has a narrow view on the subject he is addressing. Truly awful.
We hear tuners in car and motorcycle racing all day and every day for years talk about the ability to setup their vehicles based on track, conditions, and driver/rider style. These guys and gals spend 100's of thousands if not millions on their programs, but here comes Pinkbike saying in essence that a given design has only one correct setup.
To arrive at this conclusion, there are a list of things you have to remove from the equation. The below are the 3 biggest.
1) Rider style
2) Track condition (which can change dramatically from hour to hour)
3) Changes to overcome shortcomings in the bike as a result of static design, or short comings under specific circumstances.
One only has to look at a single event to see how differently various guys are on the bike. From just casual notice, Greg Minnar "appears" to ride over the front a lot more then Gee Atherton. That's significant when you consider that a tire without weight on it isn't going to have much traction.
Or what about shorter guys like Brosnan? How does his lighter weight and more diminutive stature affect the dynamics of the design? And does that affect work for Troy or does he want some adjustment to get it working for him.
Gosh people! We really aren't ignorant cavemen! Believing this stuff won't push the sport backward, but it will create an even bigger gulf between what's actually going in racing and what the fans and buyers of products know and expect.
I've had bikes with adjustable geo since 04, and even back when DH rigs had 67deg head angles I adjusted mine till it felt RIGHT. 3 years later I used a protractor and it read 62.5deg with a 13.75" bb. I LOVED it. So much for only pro's liking slack head angles. I got on just right with what manufacturers deemed incorrect for us because we're all 'slow'. So that said, and with your points, it's clear to anyone who thinks this through, that adjustable geo is only a good thing, mainly wheelbase and head angle. Leverage ratios might be pushing it, but even then it's not a huge deal to understand.
Suspension is quite simple - slack angles, long wheelbase, low bb and 8-9.5 of ramping travel is a formfactor that works very well.
It is a given that Enduro (formerly known as Freeride) will eventually end up at 60-64 HA. Watch out how your 2013 frame will look terribly steep in 2014.
Defo thinking of spacing them down to a more realistic 150mm or even dropping weight with a revelation.
Geo is dependent on the trail, the type of riding your doing, but most of all, its dependent on "you". The rider and what you like to ride, and no more is someone gonna tell me what geo I should ride, cos the simple fact is that they don't know. Only I do, so that's the line I'm sticking too
I just think that this ultra slack 60-62 HA is just pure marketing. Yes, the WC riders do need very slack and long bikes because they are much faster than the vast majority, but for the average Joe a 64-65 HA is just fine. After all, we don't ride at speeds they are riding (as much we like to think that we are), and as mega-turtle said above, that setup is awful for slower more technical trails, which are more ridden by everyday riders. And improving your skills will get you much faster than -1 degrees on your HA.
Yes you could buy a bike with different geo, but then that defeats the greatest asset in the modern trailbike's arsenal - how adaptable it is... Get a slacker bike and you can occasionally chuck it down far steeper and crazier stuff!
Finally, looking at DH bikes as an example - the pro's run them mega slack because of the crazy speeds they do. Without adjustment you couldn't ride the bikes they do, causing a massive marketing issue for manufacturers and potentially more complications with additional frames (more expensive too due to niche market). This doesn't sound too great to me...
Of course the whole thing doesn't stop someone trying to use a steepened DH bike on a xc course but they are the 'characters', not the manufacturers...
Reply: Anybody can make their bike the worst handling bike on any given day by screwing up their tire pressures or suspension settings.
"Adjustable geometry teaches us that ultimately, there is only one adjustment that results in the optimum performance for any given chassis. Once that is found, the bike no longer needs adjustment features."
Reply: And, every single bike rider is 5'10", 170 lbs, has the exact same riding style, and rides the exact same terrain in the exact same conditions.
Look, RC, the question is not whether adjustable geometry is good or bad or makes sense or not, the question is whether users want it. Some want it, some don't, question answered.
Also, as the article says, just like suspension, geometry adjustment needs someone who understands it to drive it, it'll be really easy to end up with something rubbish, I reckon far more than the 33% the article suggests.
The way i see it, geometry is a fine blend of every aspect, go changing HA, it's going to have knock on effects on more than steering and BB height, adjustable geometry gets people too hung up on one ingredient in that blend at no doubt detriment to others.
A sorted geo bike, is a sorted geo bike, it is also one of the reasons why you buy a particular bike. I believe adjustable geo is just a market feature for sales, since if you have infinitely adjustable geo, why would another bike of equivalent weight be any better if you dont understand suspension, aye?
Yes, adjustable geos is a marketing gimmick. Because it works, because we want it. It is clear that there is no one perfect geometry, and there never will be. I know two riders of similar size and weight, They ride identical bikes. they both rip, and they ride completely different setups.
If you have any level of competence as a rider, and you refuse to try different setups, you are just holding yourself back.
As a surfer first, if I had a board I could change the geo, well id save hundreds $$$ and more in time spent figurn out what works as its difficult to demo other products often.
Some people just wanna bitch about everything.
Won't subscribe to the belief in longer forks "transforming" a bike, or adjustable travel. IMO the bike is all built around an intended fork. I believe the bike follows the fork and builds really should start with this component. I like to categorize bikes by forks: Yeti ASR-5 is a Rev or Fox 32 bike, Nomad=Lyrik/F36, (160/170), most DH frames= Boxxer/Totem/Fox40/Fox180. Some frames have a little leeway, and remember, everyone has different preferences, theres no right or wrong. Just fun and funner.
2.If people would agree on that, it would put Nicolai out of business and render Manitou shim-box useless.
3.Point 2 will never happen as certain people love to feel smarter than bike designers when finding something that works better than stock! Some just crave to do something and say "why didn't they come up with that in the first place!"
I've seen people with their forks turned around claiming they love the increased manouverability in tight places between trees...
It is also sometimes a difficult thing to find both the geo and suspension behaviour you want (and you think is good) within a single bike (something I am experimenting at the moment looking for a substitute for my old Slayer). Maybe I find one with the perfect geo, but the shock rate doesn't suit me. I want it linear and it's progressive or the other way around.
So yes adjustability can bring something to reach the tuning one is expecting, but it may not be open to everybody. Not everybody has a clear idea of what he wants. And moreover this idea might be wrong, but it's great to have the chance to experiment it and in the end learn new stuffs. So you can better pick your next frame
If you slacken the fork substantially, you draw the same line but it hits the ground a lot further forward of where it was. This is known as the scrub radius, but some people have different names for it.
The reason that the axle on your fork is in front of the steerer tube (known as the fork offset, normally around 44-45mm) is to close that gap slightly and make the steering more stable as a large scrub radius will destroy feedback from the steering and make the steering axis naturally unstable.
What I mean is, if all these frames out there all gave different head angles, yet everyone is running a Fox 40 or a Boxxer which come with just a stock amount of offset, how is it compensated for? Why doesn't the pro riders bike with a really slack headtube ride like crap if his fox 40 has the same offset as mine and my bike has a 64 degree headtube?
As the fork compresses it changes as well so its more a case of getting close enough to mitigate the effects without having to make 100 different lowers for a fox 40 etc for every fork/angle combination out there.
Which is probebly why offsets have for the most part standardised around the 44-46mm point (although this is different for 29' wheel forks as the offset has to be bigger for the increase in wheelsize and therefore axle height if that makes sense?
Thanks for the info.
Once I started using the adjustable seatpost - I stopped using fork travel adjust, as you do not compromise climbing position anymore with not fully extended post.
Once I got a fork (RC2DH) and shock (CCDBA) with proper, independent LSC and HSC - no need to flip lockout.
...and while I am fortunate enough to have several nice bikes, if I did not, I would sure like to change ride height and travel depending on trail. No geometry, no matter how sorted out, is perfect for any type of riding. Flipping a chip on a shock mount before a road trip to a lift served resort is not a huge hassle.
But if it stays at the 1-2mm and 1-2 degrees adjustment who the hell cares.
If you don't care for adjustable settings, buy a different bike. There are plenty out there.
BUT this also needs a rider who is knowledgeable to understand when a 66.5 HTA is appropriate and when a 69.5 HTA works. Adjustable geo is not for novices. I have more to say but I'm sick of typing
all these are very interesting, but given the fact that the head angle is determined AND by the fork's height,that leaves us with a huge number of different setups.
For examble:
Let us persume that we're haveing 2 identical bikes but with a different brand fork (of the same travel though). That will almost always end up with 2 different head angles!
The same can be told of we "play" with different sized tires... An exxagerated example here too:
Fit a 26X2,2 rear and a 26X2,8 front. Measure the head angle.
then
Swich tires, 26X2,8 rear and 26X2,2 front..
Does this affect the head angle?
Just a thought.
/fat
That being said, I will never try the limbo chips that my bike came with. I was able to make the bike ride well with other options ( dropper, shorter stem).
ANYONE WHO VOTED THIS: If the bike is designed right, it shouldn't need a geometry adjustment feature.
There's NO SUCH THING as a bike that is 'designed right' as it pertains to geo on account of?! Everyones different!
Now, I understand that 90% of the 'tards on pb dont posses anywhere near the intelligence to comprehend such a thing as bike handling and how geo affects it, but for anyone whos evolved past that single cell amoeba noob level, having the capability to adjust these numbers can only be beneficial; assuming that price, durability, and things of that nature are not adversely affected....
Next step in the evolution is canceling out fidling around with flipchips or on-the-fly remotes.
If you dont know what that is about and how it works, take a look at www.tantrumcycles.com
www.vitalmtb.com/photos/features/2016-Trail-and-Enduro-Bikes-at-Interbike,9423/2017-Tantrum-Meltdown,97874/sspomer,2
1) Adjustments create weak points, increasing the risk of frame failure.
2) The adjustments come at a premium. Im not paying an extra £300 just so I can fiddle about with fractions of an angle. the bike should come ready set up.
3) This is the most important, its for nerds. Who gives a crap if you can adjust your H.A but 1.5 degrees or the BB by 3mm? would you notice if you didnt have the ability? No, you wouldnt. Ive met people (we all have) who claim thier bike feels so much better now that theyve changed the arc thier shock moves in etc, but theyre full of crap.
4) if you need to buy cups and spacers to slacken your bike out for DH, for example, then it wasnt designed to ride at those angles and all youre going to do is break it.
2) They don't. In most cases it's just another hole. Even some of the more elaborate ones woudn't garner a $500 premium for adjustable geo.
3) again, wrong. 1.5deg is a massive difference when it comes to how a bike feels. This comment makes me wonder if you even ride a bike or are just trolling
4) how so? We're talking a few deg at most. Name ONE FR/DH frame that voids their warranty if an adjustable headset is used.
Doth thou even pedal, brohiem?
2) adjustable frames are more expensive. thats a fact.
3) It might change the way a feels, but thats not what I said. I said that nobody sits on their bike going ' if only the HA was 1 degree slacker'. adjustments are aimed at idiots who think there is a secret formula to winning. they say ' ****rides with his HA at 63, ****has his BB at 140mm etc and try to set the bike up as if they were 5 different riders.
4) where did I say anything about warranty? I said that if you start messing about with after market adjustments then youre going to break your frame. I also said that theif a bike is DH ready then it wont need adjustments, people buying anglesets to 'keep up' with the latest trends have bought into a marketing scam. the trail they rode is the same, nothing has changed. nobody went out and rebuilt the trail to be ridden with a slacker head angle.
That is just baloney. And they DO NOT make bike more expensive. They allow manufacturers to have fewer models to respond to different preferences.
Take Banshee - they added a 650b bike, two different rear axle standards, and dramatically different behavior in low and high settings with just a hole in a mount and replacable hanger.
And no, you will not break any of it.
Querhoch, you are a kook.
Querhock, how is it you think you're so much smarter than all of those bike engineers?
But from a standpoint of consumer options, its a good thing. It makes more bike available to each rider as bikes are not one size fits all. It lets someone shop a greater assortment of bikes if they don't have to worry that the stock head angle or BB height isn't what they like to ride. Thats also a positive for the manufacturer since they can market their bike to a wider range of people.
My point is that consumers creating change in the market is good, and that the industry is not always in touch with the market. The point of the article seems to be that consumers don't or can't know any better, and should just accept what the industry hands them.
Its a good article, I just don't agree with the spirit.
Engineers and builders and companies don't always get it right. It might be right on paper, it might be right for 40-80% of the riders out there. It might even be fatigue tested. But there's always a segment that pushes things along because fatigue testing and fancy design has not addressed what they need. People that put a longer fork on a frame, or 2.4 tires on an xc bike...
Wonder why there's a huge segment of the industry focused on long travel 29ers now? And why there's 6 inch travel (or more) "trail" or "am" bikes with 170mm forks? Is it because the industry invented and designed these bikes first, then fed them to the market? No. Its because riders wanted bikes that would handle rougher terrain, and were altering their bikes to do so. And for the most part were doing well, despite all your CAD designs and fatigue testing. I don't remember seeing article about waves catastrophic frame failures from people overbuilding their bikes.
Besides that, bikes were under built for a decade, even longer. It's just been in past five years maybe that "the mountain bike" has truly come in to form (2x10, 1x10, long travel burly bikes). Largely in part due to riders "overbuilding" their bikes on their own, and pushing the limits of the terrain. This was not a move initiated by the industry. This was rider-led. Companies followed suit because they smelled the money trail, came up with terms like "all mountain" to make it seem like they knew what time was. They were playing catch up to the riders, who for latter half of the 20th century, were riding glorified road bikes. With the advent of the freeride movement, things started to change. But, that's just my jaded view of history, sorry.
For the people who does visit, like the world cup scenarios, the angle set could be good, but the can have a complete different setup on the bike, made by their frame maker!
This is just marketing...
Correct geo isn't optimized for everyone, just the majority.