Split Pivot on Devinci bikes explained by Dave Weagle

 Insert 'everything looks, feels, works like a trek' post here like every other article. Regards, TWR

 Actually Trek owns their ABP patent. Not sure how ABP and Split Pivot are different. Perhaps DW can clear that up for us in his next video?

 They're not different! ABP and Split Pivot are the same design. They're both patented because of a quirk in US patent law, that says if 2 individuals/companies reach the same design solution AT THE SAME TIME, without knowledge of the other, then they can BOTH hold a patent on the idea. So neither one is a copy of the other, neither came first, neither is better than the other. They are the same design, created by different people at the same time.

For what it's worth, I like what Devinci are about, but I breifly rode a Dixon yesterday (it was set up really badly), and I though it felt remarkably like a normal single pivot. Maybe more time on the design would allow it's benefits to show more?

 It is a normal single pivot. Split pivot is hype. Every bike has brake jack no matter what. M9s have it, Glorys have it, oranges have it. You can only minimize it.

 Isn't ABP a full floater? To me that looks like a difference...

 ABP = Active Braking Pivot, which is the pivot concentric to the rear axle, same as Split Pivot.

The Full Floater part of Trek's system isn't covered by the same patent, as that refers only to the rear-most pivot. But you're right, that is a difference between Trek and Devinci's designs.

 Still both linkage driven single pivots. Floating shocks make no difference, its just for the 'wow' factor. And the ability to say 'Our bike has a floating shock! WAZAAAAAM!'

 I thought a floating shock allowed the engineers to get whatever leverage ratios etc. they wanted out of the frame without having to compromise performance other places. Correct me if I'm wrong.

 Leverage ratio is the same, just a different shock rate, i.e. Progression curve. You still need exactly the same weight spring you'd use on an other frame with 8 inches of travel and a 8.75x2.75 shock. They've just made the specific tuning they've done look fancy.

 Actually the full floater is part of Trek's patent that was filed a year after Dave's Split Pivot. Another difference is Trek states bike rear suspension in the patent. Dave's covers vehicle suspension systems.

TREK
Bicycle rear wheel suspension system

Abstract

A bicycle frame assembly having a number of rotatable members configured to absorb shocks and impacts associated with operation of the bicycle. The assembly includes a frame constructed to support a rider and a chain stay having a rearward end that extends toward a wheel hub and a forward end that is pivotably connected to the frame. An absorber is pivotably connected to the forward end of the chain stay and extends to a rocker arm that is pivotably connected to the frame. A seat stay is pivotably connected to a rearward end of the rocker arm and extends to the rearward end of the chain stay. The rearward ends of the seat stay and the chain stay are pivotably connected to rotate about a common axis.

Inventors: Colegrove; James (Lake Mills, WI), Howes; Dylan (Monona, WI), Gonzalez; Jose (Santa Clarita, CA)
Assignee: Trek Bicycle Corporation (Waterloo, WI)
Appl. No.: 11/735,816
Filed: April 16, 2007

Split Pivot

Vehicle suspension systems for seperated acceleration responses

Abstract

The invention relates to suspension systems comprising, in certain embodiments, a pivoting means concentric to a wheel rotation axis so that braking forces can be controlled by placement of an instant force center, and so that acceleration forces can be controlled by a swinging wheel link.

Inventors: Weagle; David (Edgartown, MA)
Assignee: Split Pivot, Inc. (Edgartown, MA)
Appl. No.: 11/510,522
Filed: August 25, 2006

 ABP and Full Floater are 2 different suspension designs by trek. ABP is what the split pivot is,. But the full floater is how the rear shock is mounted to both the chainstays and the one piece EVO link, unlike how most 4 bar likage designs have the shock mounted to somewhere on the front triangle of the frame. Hope this cleared up some un certainties lol.

 Not sure about the Wilson but the dixon that I demoed was brake jacking so badly on steep decents that it kept bucking me over the handle bars by way of the seat hitting my ass on every break application.frankly i wanted to own a Canadian bike made in Canada but changed my mind after a very poor experience on the Dixon. Was it set wrong or the system accualy flawed and noone dares to say anything?

 clearly the bike was setup incorrect for you because devinic wouldnt put out a design that poor or.... you just don't know how to ride if you "kept bucking" yourself over the handles bars.

 In the end when I buy a buy a bike, physics geometry and engineering are about 5% of my worrys, parts on the bike account for about 25% worrys and the other 70% is just straight coolness factor. I personally wouldnt be able to tell the difference Im not a pro, but I do like to ride my bike and look cool. I would buy a devinci and two things would happen, I would look cool and badass, and I probably wouldnt use it to its full potential but I would look cool. Just my 2 pennies

 to tjeza, maybe i dont know how to ride budy but there is one thing i know is that the suspension on that dixon did nothing good.Rode very familiar trails that day and it was hell. Did the same trail on my chromag dirt jumper and my bottlerocket and had no issues. Wait and see, I bet that in the long run that suspension desing will not be popullar and will fade into history of failed designs.

 @ryde rup

don't know what the hell had gone wrong with your demo Dixon SP on your test ride??

I have owned a Dixon SP since February this year, and have abused the hell out of it, including serious DH runs on uplift accessed tracks, no issues with braking (especially compared to single-pivots and rocker-activated single pivots i.e. Banshee Wildcard, I have owned which exhibited noticeable brake squatting)

I also personally sold dozens of Dixon SP to customer, and all raved about the Split-Pivot suspension, not one customer mentioned any braking squatting or brake jacking (two very different traits)

its a fantastic suspension design, with fully active braking and great pedalling performance, but also great control at different speeds and bump sizes


BTW, Split-Pivot and Trek's ABP only share the concentric dropout pivot in terms of design, their bikes ride completely differently as the systems are very tuneable in terms of geometry, chainstay length, leverage ratios, brake sensitivity and physical packaging

Weagle spent a huge amount of time working with Devinci and Fox on getting the Dixon, Dexter and Wilson 100% bang-on, especially the shock tune where Devinci have the lowest LSC circuit of any RP23 or DHX5 shock on the market

the frame axle hardware is very dialled, huge bearings on each pivot (same size on each pivot for Dixon and Dexter) and simple hardware with steel bolts to reduce wear issues

 ih4life sad dude. but ya u look cool.

 Mmmmmm.

Smell that guys?

That's the smell of delicious marketing!

Don't indulge too much, or you might end up like hampsteadbandit!

 Marketing? Oh really....

Who gives a f*ck about 'marketing' when you are riding a trail...this is not the X-factor or you-tube. Does the Dixon sp bike work? Yes; damn well! That is all I could give a sh*t about... I paid for my Dixon from my own hard earned money, not because someone paid me to talk about it. I started riding in 1981, I know what makes a great bike...

 " In the end when I buy a buy a bike, physics geometry and engineering are about 5% of my worrys, parts on the bike account for about 25% worrys and the other 70% is just straight coolness factor. I personally wouldnt be able to tell the difference Im not a pro, but I do like to ride my bike and look cool. I would buy a devinci and two things would happen, I would look cool and badass, and I probably wouldnt use it to its full potential but I would look cool. Just my 2 pennies"


Wow so 70% is based on looks, rather than how it rides. I bet you wear chick pants, flip your hair constantly to one side, paint your nails, and have a murse. Your comment has to be just about the gayest femwad comment I have EVER seen on pinkbike... bar none. (now if you reply... or others reply with flamer type femwad comments, you just prove my point). There is no defending yourself against my comment what so ever. Plain as day.

Btw, if how the bike rides means nothing, then why don't you just own a walmart bike, throw some streamers, a basket on the front and back for the murse, tampons, and other feminine products and call it a day, while at the same time saving you money? O, parts specs... throw some Atlas color matched cranks, some totems, maybe a matched stem, and some matched titanium spokes and alloy nipples on and it will be good to go. So now instead of say 6k$ your at about a grand, and also have a place to put the tampons and murse while your riding? Sound good? Don't forget the place to put the number for the wambulance in the back, and also holding the concert tickets to whatver hipster or emo band is currently popular. That way, you can just impress your friends about being "real". =]

LOL. I'm just f*cking with you so don't get bent. All in good fun and for the lulz.

 ITS NOT A PURSE ITS A SATCHEL INDIANA JONES HAD ONE

 I didn't say purse. I said MURSE. IE what flamers, hipsters, emo's, cross dressors, and flamers carry. It's the new popular "thing" in which people who try to be popular by looking/acting/being gay, think they are being cool by doing so.

 People who wear chick pants carry murses 90% of the time. The other 10% they are trying to be "unique". MURSES can ONLY be manly if your carrying an AR pistol in one, with a 30+ round mag in it. Then it's just concealment and not flamerness =]

 You didn't pick up the 'The Hangover' reference. I'm dissapointed.

 I don't watch those chick movies. I'd rather be watching Aqua teen, Squidbillies for comedy, and war/horror movies for the rest. MAN movies. RAR RAR RAR! (followed by chicks jumping on trampolines).

 I feel comfortable enough in my heterosexuality to not need to over-state my character through excessive 'manly' conventions.

 Who said conventions. Or over-stating. You mentioned a movie, I just said the type of movies I normally watch. The amount of cooter I have got in the past years has been obsurd, so I don't really need to prove anything =]

 I did.

And el-oh-el @ cooter

 Ha!!!!!!

 Thansks for putting that much better than i could be bothered too summit, agree totally

 Then stop bitching and build one yourself!

It's by making small changes that you end up with something great: Porsche have been building the same type of cars since the 60's, they kept their concept (rear engined cars vs mid engine) and made it better over the years. Have you seen any changes in moto-x suspension design in the last 10-15 years?

I personnaly own a Wilson. it's simple, and it works. Why bother building something radically new every year then start over the year after? Dave Weagle started off with a simple, proven concept and tweaked it to make it work better. If it wern't good, people wouldn't build bikes around the concept.

How many 2stage bikes have you seen in the trails? Mabye companies don't like the idea of two shocks, mabye the idea is just plain stupid or mabye people are just sceptical. All i'm saying is that if something was so revolutionary and so good, companies would build it. So far, Split pivot / ABP (cocentric axle pivot) has been proven effective.

 OK, this is not the first time I've read this perspective, but I don't agree with it. We can have an adult conversation here, right?

Yes, 4 bar linkages permeate our existence. They are everywhere. How many people reading this realized that when you analyze how a bicycle (or motorcycle) accelerates, you actually need to analyze a 6-bar system?

You can bolt a wheel and chain onto all kinds of common 4-bars, making it the needed 6-bar, but will they make an effective suspension design? If you bolt a wheel onto a pair of vise-grips, will that be the best thing ever? How about the hinge that operates the lifting motion on the hood of your car? How about the 4-bar linkage on the shroud of a common chop saw? Are these the new revolutions? Really, it's the wrong way to look at it in my opinion.

If you read any suspension patents, you will very quickly realize that the method that I used to develop dw-link was completely different and novel compared to anything in the past 120 years. It is what it is, and I don't want that to come off as anything other than a fact. dw-link was devised to hit a specific range of performance that was not being met by other designs. I understood the physics problem first, then designed a solution, then synthesized linkages to meet that solution. Notice that the linkage design part came last, not first.

(continued below)

 Coming into this, I never had any intention of "licensing" or whatever. I was approached by a host of companies, and their offers convinced me to forego a career building my own designs under my own company name, and work with them to build their ultimate bikes better. This is why I never built a full suspension Evil when I owned the company. Iron Horse literally made me an offer that I could not refuse. Ask my close friends, I obsessed over that decision. I was afraid of "selling out".

The suggestion that "the dw link is extremely similar to many other patents that have existed far before, just with minor alterations in order for him to gain the rights" is comical. Using your expert advise, why don't you give me just one or two patent numbers or older designs and tell me how the design is so similar. How is the anti-squat profile similar? How is the braking squat profile similar? How does the design translate into building widely varying leverage ratio curves useful for driving spring-damper units at varying velocities that are suited for bicycle suspension use? What about manufacturing related requirements? I think that once you really delve into the problem, your perspective just might change.

There are plenty of great bikes out there. I am really happy to be a part of some of them. I am even more happy when I get to ride them. That's what it's all about. Riding and having fun. All of the rest is just noise.

Have a great weekend guys and girls!

Dave

 Thanks for the great explanation Dave! The split pivot system makes much more sense to me now, as well as suspension design as a whole! What is your opinion on Marin's quad link setup? It seems to be able to control axle path and leverage ratio in a similar way to the DW link, but with greater isolation and control. Am I wrong in that assumption?

 Well, I think Dave just killed this internet engineer debate. That was hilarious. Summit800, WTF has you made? How many of people are riding and buying your designs? I am sure Dave really appreciates you "giving him credibility" but he has made a career and has become a legend in the MTB industry, you are a pinkbike forum warrior. It's a textbook self esteem problem.

 This is why industry shits all over fresh engineers. You don't actually know your head from your own ass. When you graduate school next year, you won't be an engineer you are simply an EIT. You know nothing, the sooner you realize that, the better you will do in your career. Trust me. I interview engineers and live with 4 of them, and have half an engineering degree myself. You are challenging one of the greatest suspension developers of our time, with some sort of data logic, and bravado. Unlike you, he has actually designed, tested, ridden, bicycles, that have sold in large numbers. Congrats you can calculate the area under a curve. When you become a P.Eng, then maybe you might actually know something. Until then, sit down, and take in as much as you can. I give Mr. Weagle mad points, for responding to these comments, that alone can be a risky venture.

 i think the point is to stop f*cking around with "new" wanna be suspension systems and start making them affordable to a bigger audience, bikes nowadays are way more capable then any of us can ride them.... im not trying to say to stop the research, but seriously dear bike industry i will not buy your shit because it has any new patented suspension technology hoax inside, your customers are not dumb!

Make Bikes more affordable! more bikers = more money, consider it ;-)

 You know what I learned in school?

How to properly use an apostrophe.

 haha!

 whats that?

 "obviously american school system pretty shit." What school system taught you how to form sentences????

 Summit800, you clearly don't understand Dave's work, and you're in no position to offer accurate criticism of it. What you are completely failing to understand is this:

With DW-link, Dave started with a RESULT he wanted, and worked backwards from that desired result (which is in fact a number of characteristic curves, which you may or may not understand) until he got the LINKAGE that generated it. The linkage layout in terms of pivot position isn't actually patented, but the ways it generates its output curves are. Yeah the pivots are in VAGUELY similar locations to every other bike out there, but small changes make big differences. Putting in a rail or some novel linkage layout or whatever doesn't necessarily make something perform better!

Pretty well every other system out there prior to his work was doing more or less the opposite - designing a linkage that happened to demonstrate a certain characteristic. What nobody else was doing before DW came along, was accurately considering ALL the acceleration-related forces acting on the suspension (ie the system inputs) and tuning a "simple" linkage to give exactly the responses he wanted (ie the system outputs).

Remember this, because as an engineer it's something you'll need to know: Novelty offers no benefit over accurate tuning.

 summit800, I work in a different field, mental health, but the process mirrors engineering: go to school, absorb vast amounts of knowledge, think you know everything, then over the next 10 years actually become competent at what you do. There are MANY incredibly talented and creative people who came before us. Almost every novel idea we come up with has been thought of by someone else before. There are those AHA moments when material or manufacturing technology catches up to theory/design and "new" ideas are put into production. The theoretical knowledge obtained in school is only useful when coupled with the intricate spiderweb of experience that allows us to fine tune the efficiency in which we apply the theoretical knowledge to appropriate solutions rather than going through many failed experiences.

In my field, I felt pretty clever seeing a link between a certain depression profile that didn't respond well to medications or therapy, and high co morbidity with ADHD. I thought I was on to something new, but over the past 6 months, I have seen numerous studies published highlighting this link. The shift 4 or 5 years ago to look at disorders based on brain chemistry rather than symptoms shifted a lot of people's thinking, and many other, more clever, more resourced people have published their work before me.

 "the reason such links like the dw have so much recognition from bike manufacturers is due to their ability to provide reasonable characteristics at low cost of manufacturing."

What the eff do you think drives business? THIS. Having a GOOD working DESIGN made with LOW COST.

What do you think Lawwill did. I guarantee 90% of designs patented today (currently used) wouldn't be here without lawwill. Or FSR. OR any of the others. People said the same thing when FSR came out. When Lawwill came out. Each progresses ideas. Each progresses technology. While I ride a linkage driven single pivot on one bike, and a single ultra high rearward travel bike on the other bike, I still understand what new tech does. Sure it doesn't replace older tech, but, like canfield did with the Lahar, they improved and made it a multi-pivot rearward travel bike. Tech is good, and in the case of Canfield improving upon Lahar's ideas suspension wise it was night and day in feeling.

People are brain dead with all this gimmick crap. I think shit is gimmicky more than many others, BUT, technology is NOT. I just think fanboys who go to a suspension because a pro rides it, rather than how it actually rides is lame. After all, how many posery lamers did you see with Iron Horses when Sam Hill was winning? How many people did you see riding V10's suddenly when Pete changed from Orange to SC, how many more people did you see riding demos when Hill went to SP? That shit makes me sick.

 DW is simply offering something different. I don't think his designs are the best *for me*, because I don't agree with the high anti-squat and low pressure shocks, due to the pedaling energy robbing aspect of anti-squat. Others seem like that though, and buy up premium priced bikes featuring DW Link suspension. It certainly can feel plush on the downs due to the low pressure in the shock and a well designed leverage ratio curve to utilize the shock and, on the ups, can be forgiving on the bumps and sticks to the ground well as long as you have good pedaling form, but you'd go up faster on other similarly spec'd other bikes. Of course it differs based on various models, so not all DW Link ride the same. They all have high anti-squat though, from what I've seen. The pivots just seem too high in relation to the chainline.

IMO, a perfect design is one where you can't take anything away from it, yet it does everything you want it to. Simplicity... I seem to return to my more shock dependent, more pedal neutral, single pivot FS bike, just because it jets and I really value that feel in a bike. I am still working on clearing a number of technical climbs and I don't plow through chunky rock gardens on it, but I love it nonetheless. I guess the SoCal terrain I ride is just too smooth for DW Link to show much of its good side--a Mojo SL felt like a pig and a Flux felt a bit like a land shark and bottomed out too easily (my main ride was a Ti 29er HT at the time; now a Superfly 100 and AS-R7).

One more thing, don't call the ProPedal lever adjustment low speed compression.

 Varaxis, anti-squat does not "rob pedalling energy" - in fact the idea of properly tuned anti-squat is that there is NO energy lost. "Bobbing" of the bike dissipates energy as heat through the damper, preventing the damper from moving (either via a precisely calculated amount of anti-squat or a lockout on the shock or whatever) prevents energy being wasted. The way it works is that the forces trying to compress the suspension (rearwards load transfer to the rear tyre under acceleration being the main one) are balanced out precisely by forces trying to extend the suspension, leading to no net movement of the suspension DUE TO PEDALLING FORCES.

This means that if your pedalling forces aren't trying to make the suspension compress or extend, you don't have to compromise any aspect of your damper setup to try to reduce bobbing (though you obviously still have to make other compromises, like using LSC to adjust stability vs harshness - another discussion altogether). It just removes one more variable from what your suspension setup needs to cope with.

There are a couple of REALLY detailed discussions of anti-squat on Ridemonkey, see www.ridemonkey.com/forums/showthread.php?244131-Pedal-Feedback&highlight=anti+squat and www.ridemonkey.com/forums/showthread.php?244241-Anti-bob-chainrings&highlight=anti+squat if you're interested.

Also, the Propedal adjustment does in fact adjust low speed compression, but it does also generate force at zero speed.

 Socket, your theory seems to be that bobbing = energy loss and that minimal bobbing = efficiency. Locking out a suspension so it cannot act is one thing, but leaving it free to move, but countering the squat from accelerating with anti-squat is basically producing a force to counter another force. That counter force needs energy. Anti-squat is produced by chain tension. Chain tension is produced by pedaling forward. If some of that chain tension is being diverted to the main pivot arm to produce anti-squat, then not all of it is going into driving the wheel. That energy is lost, canceling out another force. It's like pushing your hands together, or holding your body still in the lowered position of a squat. Just because there is no movement, doesn't mean there's no energy loss. Pedaling neutral bikes have no pedaling induced squat or anti-squat and are theoretically, the most efficient, since all the pedaling effort is going into the the wheel (but there's nothing to prevent the squat from accelerating, besides the shock and pedaling technique). FS bikes with pivots along the chainline spend more time in the pedal neutral zone, depending on what gear you're pedaling and where the rear suspension is in its stroke.

DW Link has over 100% anti-squat in the first half of its stroke (120-140%, if I recall correctly). Check the anti-squat curves on some of his AM bikes. This is somewhat balanced by running a lower pressure in your shock, in order to minimize bob. Tuning sag is critical on a DW Link, as it is very position sensitive. DW designs his bikes to not be shock dependant, not requiring ProPedal (or Boost Valve). I'm not a believer in that, but I won't argue that his designs strike a good balance in what riders want in a bike, with a bob-free ride with excellent traction and rear end stiffness for good wheel tracking. I just weigh one of the downsides to the DW Link quite heavily.

 Designs often emphasize wheel path and how pedaling forces want to pull the rear axle forward, and if wheel path is has any horizontal curve to it, the pedaling forces will go into pulling it forward and therefore lose efficiency. That's why designs like Maestro and Horst Link aim for a vertical wheel path in the part of the stroke where riders will likely be pedaling. It's just too bad that plowing over big bumps doesn't translate well into that vertical wheel path and the tire and wheel eat up a lot of that impact, hanging up the bike and losing momentum, possibly flatting or damaging the wheel, etc. Landing level and flat, translates better into that vertical path than one that starts with a rearward path, but generally most impacts translate best into a diagonally rearward and upward path, which is the classic wheel path of a high single pivot (which this Split Pivot design has). Basically, everything has ups and downs. No FS bike is as efficient has a HT, even if it's bob free, unless you lock out the suspension (with the shock, not the drivetrain).

I care about pedaling efficiency. Many don't, caring more about the adrenaline rush on the downs. This Split Pivot design sort of is skewed for that, from what I can tell without riding one. I kind of want to see the Zerode with a similar concentric pivot and isolated brake design.

Anyways, this is all abstract generalized nerd talk. Feel free to try and counter my points when you manage to compare DW designed bikes to other bikes of similar design intent and go climb them uphill, which I consider the true test of efficiency. The truth is in the ride.

ProPedal sounds like what LSC damping can do, but they're different. Darren of PUSH explains: forums.mtbr.com/2927421-post31.html

 Here's a bike that's in dire need of Split Pivot:

www.youtube.com/watch?v=e2KRlsBwa9Q&feature=player_detailpage#t=70s

A DH bike with its rear brake mounted on its main pivot arm. Look at that thing move. Now imagine it if the brake were mounted on the "chainstay". Not perfectly isolated, but compared it's original design... that should do a great difference relieving the brake jack (or brake squat... looks like it stiffens up to me under braking). If the pivot was at the axle, the "chainstay" would be even more neutral.

This DH bike has neutral pedaling, does away with derailleurs, and centralizes all its weight, leaving less weight unsprung. I wonder if this could be the future if they meet up with DW. They also have a carbon XC version too.

 Sorry Varaxis but your understanding of energy is very much flawed. Force does not equal energy. Work equals force times DISTANCE. The amount of work done is equal to the amount of energy consumed, therefore if there is no movement, there is no energy lost. Minimising acceleration induced motion of the suspension is absolutely the number one priority when it comes to maximising pedalling efficiency of a full suspension bike - even the generally retarded bike industry is in overwhelming agreement there. Creating a force to oppose another force does not waste energy, in fact you can generate an infinite range of forces by utilising different arrangements of levers (in this case, a linkage) to manipulate the original input, without expending ANY energy whatsoever. This is first year statics for engineers, and it's really not up for debate in the scientific world.

(cont'd below)

 What you seem to be confusing is pedalling "feel" vs actual efficiency. I have owned a DW link bike and now own a directly comparable bike from another manufacturer, that has a different variation of a 4-bar linkage rear end with much greater anti-squat than the DW-link bike. The DW-link bike felt dead when you pedalled it, but it didn't actually move up and down much. The other bike FEELS like it accelerates hard because there is a very firm feel at the pedals, but in actual fact it's extending the suspension during the peak force region of the pedalling cycle, which is simply wasting energy. If you want to understand more about anti-squat I suggest you read the Ridemonkey links I posted above, there is more detail on anti-squat and how it works in those threads than the entire rest of the internet combined.

ProPedal is LSC that can generate a non-zero force at zero speed, unlike constant bleed LSC circuits that you usually find in DH shocks. To quote from your link "Is Propedal compression damping? Yes. Propedal is part of a complete compression circuit.".

BTW - I wrote my thesis on MTB suspension, I work with a suspension tuner here in Australia, and I own a shock dyno. I do have some idea what I'm on about

 I'm well aware that work = energy = (force)(distance) and that forces that balance out to produce no movement create static equilibrium. To create equilibrium against the forces that produce squat under acceleration, *pedaling forces* go into creating that opposing force. It's not free and it's not constant. Rather than saying canceled, I should say that force is "returned" by creating a ride with minimal bob. Simply put, you cannot tell a non-engineer that a FS bike with no bobbing has no energy loss and that all their pedaling forces are going to propelling the bike forward as a hardtail would. I consider the anti-squat more like a "tax" that is taken out of each pedal stroke. Maybe I should also mention another downsides to anti-squat, which is pedal feedback and the obvious stiffening/extension of the suspension. At least it's better than riding a pogo stick, but any anti squat above 100% is excessive, in my opinion. DW has his own opinion and others agree, but his anti squat curve stays high throughout the travel on many of his bikes, when it's only necessary for the first 25-40% of travel and should drop off after that.

Observing the suspension profile in Linkage (www.bikechecker.com), the Wilson seems to have an anti-squat curve that starts at 130.9% and steadily drops to 98.2% anti-squat at full travel (not sure what gearing is used in the sim), with a total chain growth of 42.3mm, producing 22.86 degrees of pedal kickback. The brake forces start out at 96.9% anti-squat, very close to neutral (100%; over 100% is brake jack and under 100% is brake squat), but ends up at 15.4% anti-squat (heavy squat).

It's arguing semantics now, more or less. ProPedal does attempt to damp out low speed compressions, but does so in a way different from normal LSC found on Fox forks and the RC4, as you say. What you describe is what many call platform.

Have a copy of your thesis online? Read one that praised Giant's Maestro (Glory) and I'm curious how yours reads.

 Well, here's my equation....bikes + jumps + mountains = awesome...I'm pretty sure you can't argue that boys.

 Varaxis, read the threads I linked to on Ridemonkey and you will see why "100% anti-squat" is not necessarily the optimum value. I cannot stress enough just how much useful information is contained in there!

And actually, yes I can tell anybody that a FS bike with no bobbing is no less efficient (save for perhaps slightly more flex and almost certainly more weight) to pedal than a hardtail. I don't know how you're coming up with this stuff but it's not based on any physics! You can generate whatever force you want in as many places as you want (theoretically up to infinity but in reality stuff breaks instead) by increasing the leverage on whatever, but if those forces are opposed in such a manner that there is no displacement, NO ENERGY IS CONSUMED. If you want to disagree with this, there's a guy by the name of Newton whose theories you want to publicly dispute. It's really not up for debate in the slightest - please read a statics & dynamics textbook.

 You should also be aware of a few things with Linkage:
1. Most of the files input in its existing library are inaccurate to some degree. With some bikes/designs this matters quite a bit, with others not so much. The current generation of DW-link bikes have links that are much too short to be accurately modeled by clicking on photos, and so chances are the data you're looking at is substantially inaccurate. As a general rule, the longer the links, the less inaccurate Linkage is. The acceleration profile for the Wilson would probably be reasonably representative, but the braking characteristics are reliant on a very short link with a lot of rotation, and small errors in the coordinates of those points will give large errors in braking profiles.
2. Anti-squat percentages under acceleration are heavily dependent on gearing choice. The percentage anti-squat varies according to what gear you're in, what point in the travel you are at and the gradient of the ground you're on. Looking at numbers like that without even checking what the gearing is, is more than likely going to give you entirely useless numbers.
3. The braking force percentages you're reading are actually anti-RISE not anti-squat. 100% anti-rise is not considered "neutral" braking, in fact it is a reasonably high level of pro-squat. Again, please read up on this.

We may be arguing semantics, but that was exactly the point of the debate you brought up regarding whether Propedal was LSC. It is a compression adjuster that affects motion of the damper at low speed, therefore it is a form of low speed compression adjuster. Yes it also has a platform effect, doesn't mean it doesn't affect low speed compression.

Jump on RM and search "thesis" in the DH forum and my thesis will pop up. The topic was the interaction of the rider with the suspension, not an analysis of linkages however.

 I really enjoyed both those threads, especially the idea of a biopace style chainrings to balance out the non constant power input throught the drive. Some interesting stuff Thanks for pointing them out buddy

 Seriously, we're on pinkbike. Most of the people here are anything but hospitable or intelligent. We're like.... 4chan lite.

 "morewoods? pretty sure delfs and rennie were breaking those weekly" - the man at Morewood confirmed that this is BS and not fact. Just a heads up, be very careful what the internets tell you.

 I know that for sure personally. And I still see them falling apart all the time here with my eyes

 I asked directly and was told that is BS, because I had heard the same e-myths and wanted to find out the truth. I can only pass on what I was told.

 yeah cuz the guy at morewood is gonna totally be up front about something like that

 No, because if someone stands by their word then I trust them because they can be called on it and if the truth subsequently comes out that they bare faced lied, then they're gonna look really dumb and lose all credibility and ruin their reputation. So until MD or NR come on Pinkbike and tell me they broke x number of frames and how/why, I'll trust the guy at Morewood over any other Tom Dick or Harry random Pinkbike cyber-hater.

 gnarbar bigtard is a troll. Don't mind him. Feed the trolls... be trolled. There is no arguing with him because 99.9999% of the shit he spews out of his bull mouth is bullshit. Straight and simple. He is good at one thing, and one thing alone.... and that's trolling. PERIOD.

He also knows as much as a 5 year old which was born from a crackhead, and kicked in the face, beat with a rake, and thrown in the dumbster. (no not dumpster, this is more derogotory. Only trolls deserve these descriptions.).

Glad to see you back trolling again tardo. Did you ban expire finally??? .... Loser.

Btw, bigtard, I just put some more dogfood in your families dish. Enjoy much? Wait, it wasn't troll food... o well, trolls eat dog food as well.

 Ha ha ha ha ha. I'm laughing out loud. But the real kind where you actually laugh. not the kind where you write lol. Oh and don't worry. I was never banned, well maybe for a few days. I was actually too busy to bother fucking with you. busy doing all the things you wish you could do with your time but you can't because you're a nobody. Myself on the other hand. I'm just a nobody on pinkbike. And gnarbar You just admitted to being a sucker The dudes you'd like to hear from about their bikes won't talk to you about it. Because they're professionals. Bigtard isn't of course. But he knows these things.

 What, f*cking with other guys like you just blaitently mentioned? Cool stuff. Probably stalking part time, and going to flamer bars the other eh?

And you were never banned, but, "well maybe for a few days". Hmm, seems a bit contradicting doesn't it? You got banned and you will be banned again. You are one of the most infamous trolls on pb, and, by your words not mine, an open queer who likes "f*cking with other guys".

Have fun with that one buddy. Glad you got a laugh out of my comment. But no, I don't swing your way, so that laugh only goes so far.

Btw, you mention having a life, but yet, you have more hours racked up trolling on PB than any actual moderator on here has. Hmmm. Considering I spend about 1-3 min every few days on pinkbike, you must have much less life than me in order to spam and troll worthless comments on almost each and every post on pb. Like said, It's not just me who knows you. We all think of you as the "PB TROLL". And not in a good way. Your trolling is more on a stalkative disturbing manner than anything. A+ stalkers. Wonder if you are on the S/P listings online?

 @rffr....bigtard is a waste of skin; the end

 I would also like that bike. Dave

 mmm, Mini-DH Wilson. I do love my 6point.

 Go buy the Giant Reign X0

 Had the same experiance! The trek just seemed dead compair to the wilson. The wislon was just alot more lively and active. It also cornered like no other. Can't wait to pick one up for next race season!

 I don't want to speak for Devinci, but I always thought that this video was supposed to be an educational advertisement of sorts. Devinci asked me to explain the unique parts of their design and the Split Pivot so that more riders would understand the deign and hopefully be interested in giving one a try. I don't really know how it could have been done so that it would not really come off with an advertisement. I mean, look at the comments on this page, people are going to see things the way that they want. If this gets one more person interested in getting out on a mountain bike today, makes someone think twice about trying out a Devinci or Split Pivot, or sparks the imagination of one young engineer, then I am happy. Dave

 Agreed w/ Dave. Solid info here and great looking bike. Looking forward to swinging a leg over one of these soon!

 I agree. I appreciated learning more about how split pivot works. However, the section of video around 4.20minute mark, explaining how brake forces are separated on the Wilson, could have gone a little more slowly, and detailed a little better how the "brake link" and "wheel link" float independently. When you what the CAD footage and the real footage of the suspension moving though it cycle, it's difficult to see the change in the position of the wheel and brake links in relation to one another.

 That is some good feedback guys, I appreciate it. I definitely talk too fast, I actually have to consciously think about it at times. I will look at that video in the spot you mentioned and give the guys some feedback. If we can make it better, then we should! Dave

 would be interesting to visualize the "forces" that go throught it while in action like CAD footage maybe? i think it would make it alot more understandable.

 Exactly. No information here, just a bunch of strategically placed keywords. The first sentence of the bike radar article quoted explained more about the concentric pivot then the entire video.

 Dave, your professionalism in handling this comment section has reminded me why I would be terrible in a customer service job.

 Sorry you're bummed, crazy-canuck, I read "Press Release" on the home page, and clicked the link expecting the company's point of view, explained by D. Weagle. I recieved just the information that I expected, and if you'd read the heading "Press Release", you also should have been prepared to hear that.

 I don't know why everyone is hating on this. I just got back from whislter and test rode the session 88, commy dh supream v3, cove shocker, demo, giant glory and finally my two fav bikes the pivot phoenix and divinci wilson sl. The wilson sat alittle more into its travle then I was use to (idk if that was the design or what) but thats really my only complant. It really showed its stuff in the steep gnarly stuff. I am either getting the wilson or the phoenix for next race season. Both uses daves design and both out rode the compition by far in my books. I just love how composed both bikes stay through the ganrly stuff and how well they brake in rough secions. The only reason I like the phoenix more is because it sits higher in it travel and skips over roots instead of sit into them so you can push the bike that much harder but deffently both are the best bikes out there to date! Nice work with both of those amazing rigs dave! looking forward to trying the dhr some time too! Keep up the good work!!!!

 Hey Dave, first off I want to say thanks for really looking at the comments and taking the time to respond.
Secondly I feel the need to apologize for my first comment. Somehow when I reviewed this short article I missed the video, whether it was not presented on my screen, or I just missed it, I don't know. So now that I have seen the video, I actually thought it was very informative.

As an engineering student myself, I would be interested in more detail about how a bike with a single pivot wheel path is able to pedal so well on multiple chain rings (1:10 in the video). To my knowledge it is largely up to the loaded chain path in relation to the main pivot.

Another question I've had is at 4:55 in the video. Many different designs claim to separate braking forces by floating the brake. I would like to know how exactly it separates them without a "brake therapy" styled link rather than just continue to take it for granted. It seems to me like much of the braking force would still be transmitted to the shock.

Thanks for reading my little book.

 all I know is whatever they did WORKS. One of the best braking bikes I have ridden. deffently on par with the trek if not better and absolutly better then the cove and dh supream v3 from my experance. I got to log 3 days on this beast and it rips.

 Someone's drunk... Again...

 If you look at the front pages of the Split Pivot patents you will see that both Becker, and Crestone Peak were disclosed as prior art, and the patents were awarded as novel over that prior art. Also, if you read the actual claims of the Split Pivot patents, I think that you will see the elements described that do not exist in other references.

It's risky business for any company making suggestions that suggest people or companies should not respect IP. I would not suggest that.

To answer your question directly, bike consumers pay about the 1/5 the cost of a low end rear shock, or less than the cost of a single butted aluminum top tube to use my designs. I personally believe strongly that the performance of the bike is improved significantly more by my suspension work than an fancy top tube. You may disagree, and that's OK.

Have a great weekend Bradflyn,

Dave

 I have the same feeling about my Dixon SP


its the modern incarnaton of the original "mountain bike" - my first MTB in 1986 had cromoly steel frame and fork, Shimano drivetrain with thumbshifters and big balloon tires - I used that bike for everything!


today I went riding with my buddy Jesus John, he was riding a 2011 Specialized Enduro with the very capable FSR suspension

we rode for 5 hours flat out on steep fireroad climbs, steep woods decents, rolling singletracks, big tabletops, rough off-camber rooty trails and super fast downhills with big berms and braking bumps

he knows the trails, so I rode on his back wheel to get a sense of direction

I had no problems keeping up on my Dixon, and no issues of "brake squat / brake jack" as some have commented..

Weagle has done an awesome job on the Split-Pivot, and Devinci have done an awesome job on building the Dixon, no complaints from me!

 he'd ask you what you had in mind and then patent it so you cant use it

 You need a prototype...who cares if the welds look like crap. You could also draw it out really well, model it in 3D, and then use some animation to show how it works. Still, if you want to ride it, then get your hands dirty and build one!

 Here's my advice to any young suspension designer with the new hot design that's going to make everything else obsolete.

1) Don't show it to ANYONE, don't talk about it, don't describe it, and certainly don't offer it for sale, license, or anything that could be constituted as such until you have an actual patent AWARDED.
2) Nobody is going to pay anything to any unknown person without patent protection, and at the same time, some success in the market to back it up. There are plenty of known people shopping designs around as it is. Personally I don't shop my work around ever.
3) Working in bikes can be very rewarding, but at times it can also be a thankless job. Many companies would rather steal your design straight up. I have learned the hard way. If you can't handle that kind of stress and not lose your mind, you may want to try a different career path.
4) If you don't have a patent, then anyone can use your design. If you have a patent, you need to have the $$ to protect it. A patent is not a right to build or sell your idea. It is a right to stop others from building or selling it. Read that twice and remember it.

My suggestion if is to start a bike company, apply for patents, and 3-5 years down the line when the patents award, build something with it using the experience gained over the years of building bikes and a brand to add to it's value. Suspension designs are a dime a dozen out there. Do a patent search and see what I mean.

It's a tough world out there but those with real heart, dedication, and above all the willingness to work tirelessly sometimes get a small piece. No guarantees though. Plenty of people have spent their whole life working their ass off with no reward. Never going to know unless you try.

Dave

I'm sure that's exactly what you expected chaz dog...

 Chaz is just upset that his suspension design didnt take off, at least I hope thats the reason other wise hes just hating for the sake of hating.

 Thanks for this advice Dave. As an engineer in training, your work inspires me to build and design bikes!

 Thank you for the advice. I want to remember it as I read up on proposed reform of patent laws, and how this industry could be affected by those changes. There needs to be a distinction made between patent trolls and designers without manufacturing capital.

 Split pivot was patented a year earlier than Treks' ABP.

 split-pivot.com/Weagle%20Split%20Pivot%20Patent%207717212.pdf
patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7,837,213.PN.&OS=PN/7,837,213&RS=PN/7,837,213

yes, you're right it was filed a year ago, but took a patent the same year. Well, it means that Trek sucks, i don't care. Monopivot WTF!

 Customers of gravity inspired sports equipment respond to many stimuli; one of those is an understanding of the product we are buying. Admittedly many may make their purchase decision on how cool it looks but that is up to them. I want to understand what I am buying and how it will add to the enjoyment of my riding, so please, can someone, somewhere in the industry make a ""Buyers guide to suspension designs for dummies""

You have one pre-order right here.

To get an idea of the kind of thing I am thinking of, watch any of Dave Garland's (Team Mechanic at CRC Nukeproof) "how to" videos; a great ability to explain to anyone, even someone like me, what is important when trying to maintain your bike. I need something like that about frame and suspension design or my head is going to explode.

Thanks for reading.

 I test rode the wilson in whistler and have to say it rides amazingly. I would check out the wilson or pivot phoinex if you are serious about racing. Other wise I would go with just a free ride bike and not worry about having a full blown "dh" rig.

 i've been sifting through all the comments. lots of negative nancys out there trying to discredit your work. all i have learned from this so far is that you have studied the problems of bike suspension plenty and are always prepared to take the higher road when it comes to arguments. well done, the bikes look like great product!

 nada

 Oh?you love me long time yeah?


hahaha

 wouldnt that be asian? correct me if im wrong, lol

 hahaha ye!

 Second that! Do you think they'll bring out a women-specific-design called the Rita?

 Yeah, it's not even rideable...

 I don't know if I would go as far as saying it's not even ridable. Devinci's got a good line-up of bikes and their Wilson is one of the sickest single pivots out there. I must say, locating the link down and around the BB is a trick way to keep even a lower center of gravity. It's just that it is still a single pivot. I personally have not had good experiences with single pivot bikes' ability to take square edged bumps and so on. First it was Lawwill, then the FSR horst link, VPP, DW link... all seemed to be progressing and it seems like a regression to refine a single pivot except for maaaaaaaybe stiffness, but that's less and less of an issue these days.

 Hey Nick, The Split Pivot is a single pivot for acceleration, and a multi-pivot for braking and leverage ratio control.

 Ok, I'll give you that. And loads better than any Trek as well.

 I don't know where you worked, but where I worked (Charles Stark Draper Laboratory --- DARPA) the testing and documentation process was scripted and exhaustive! It made ISO look like a teenager's high school notebook.

 No disrespect, you seem like you know what you are doing and mad props for sticking it out there doing what you love...I've been around to all the bigs, and docs are tight/overdoneon the production side, but R&D is fast and dirty...take it easy.