I don't think that the new Trek bike is doing anything that hasn't been done before by FSR bikes and other bikes. If I was developing the kinematics for that bike they would have been drastically different.
DW's new suspension design. the split pivot.
- Thread starter dhkid
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You seem to be really caught up by the fact that this can be used to easily mimic an FSR bike, which is true. However, the fact of the matter is that the design can be used to recreate any single pivot/floater design. And there are many single pivots that behave wildly different than FSR. Manufacturing costs will be a little higher since sex bolts costs near nothing, but with some companies manufacturing custom aluminum style sex bolts (Spec for example) that could be a wash.
From a strictly dynamic/kinematic standpoint your are correct, but lateral stiffness can be increased (again this is subjective as too stiff can be a negative in my eyes) and again cost of manufacturing should be around the same compared to higher end frames.
What I'm interested in seeing is if the patent is written in an all encompassing way so that it protects from any style of concentric axle pivot placement design or if it is the actual kinematic design or a combination of both. That will probably have the biggest effect on the industry and consumer.
Thank you for your reply. I´m pleased to see the ongoing implementation of your patent pending "Split Pivot" first in the BERGAMONT bike report from the recent Willingen bike festival (http://www.mtb-news.de/forum/showthread.php?t=341608). I personally like your suspension design very much not least because of the mechanical as well as the aesthetical simplicity (looks more like a true bicycle than a downsized motorcycle). IMHO seemingly simple, clean looking mechanical designs featuring a perfect function are ingenious, so does your invention.
Wilhelm
AMEN
seriously: i see the split pivot on gearbox bikes only...
rest sould be the dw-link which works great for me.
finally the world needs a gearbox which works fine....
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Cheers for the lengthy response and the links Dave, I'll reply again in a couple of days when I've digested those patents. Also I apologise if I came across as bashing you or the design out of hand, I realise my militancy about performance honesty/marketing claims sometimes comes across as condescending or ill-mannered. I do appreciate the time you've taken to explain a lot of stuff to myself and the rest of the world, I hope you realise that the reason I am pretty brash with this kind of stuff is because I am more interested in real technical merits than advertised ones, not because I have anything against you or anyone else.I love that you have become such a confident individual Fatman, think back, just a couple years ago you would come here and ask question after question about suspensions, how they function, etc.. I took a lot of my personal time to humor those questions and to share some of the information with yout that's just not available in books. Today you are here and making definitive statements about theoretical suspension performance. I think that its great to see how your knowledge has grown, and I can't help to feel but just a little bit responsible. Bravo!
That being said however, there are a couple of places that your statement is at least not entirely accurate.
First off, from a structural standpoint, the Split Pivot design does have the potential to be stiffer or stronger for the same weight. Its simple physics. Less of a moment arm on the pivot = less force in the pivot = less material in the pivot.
Your suggestion that the Split Pivot's dropout pivot is in some way more complex the FSR is amusing at best. In fact, the exact opposite is true. Take apart both systems and count the parts. Typical FSR bikes actually use sex bolt type pivots (for a couple of reasons), and because of that the FSR dropout has MORE parts than the Split Pivot dropout. The concentricity of the Split Pivot dropout also has the advantage of letting the designer use a thru axle type connection straight through the entire chainstay pivot, and potentially stiffening the interconnection even more by creating in effect, one large double shear connection. This is not possible with the FSR layout. Of course, all of this assumes that you have an engineering team that is optimization minded and capable of eliminating weight where they need to. Specialized is awesome at this kind of thing, and they have their FSR bikes designed to the limit from their years and years of experience with the design.
From a performance standpoint, you are correct only if you are talking about identical linkage arrangements. With identical pivot placement of all but the dropout pivot, the Split Pivot and FSR designs are capable of some very similar levels of performance, but only within specific kinematic layouts. There is a wide range of engineering latitude within the Split Pivot patent portfolio that does not exist in the FSR portfolio. A much wider array of link layouts, and because of this, performance characteristics can be achieved with the Split Pivot design.
Feel free to read the Split Pivot patent applications and make your own assessment by following the links below. You will see for certain that there are specific performance characteristics cited in the applications that have never been implemented or are even capable of being implemented with the FSR design.
US20080067772A1
http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=2&f=G&l=50&co1=AND&d=PG01&s1=Weagle&OS=Weagle&RS=Weagle
US20080073868A1
http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&co1=AND&d=PG01&s1=Weagle&OS=Weagle&RS=Weagle
The reality is that suspension characteristics and performance are directly related to the kinematic layout of the links in said system. Why would I spend my time working to optimize someone elses design when I could spend the same amount of time optimizing my own. I know that there is a good deal of capability within the Split Pivot design to build bikes that are stronger, lighter, and better performing than some of their counterparts. Like I said earlier though, you need an engineering team with the skill and knowhow to make it happen. I think that you will be happily surprised with the ride of the true Split Pivot bikes when you get a chance to ride one. I wish I could tell you an exact date when that will be, but thats not something that is in my power.
Hope this clears some things up or at least motivates you further to keep learning.
Dave
Can't remember if it was on this thread or on another, BUT
were there any releases of Split-Pivot bikes at Interbike this year?
DW (a while ago...can't remember if here or on another forum) said that we should be seeing some unveilings this year.
I know that the whole "Turner news" kind of took the spotlight and I thought I may have missed some Split-Pivot info.
Just curious.
Thanks!
were there any releases of Split-Pivot bikes at Interbike this year?
DW (a while ago...can't remember if here or on another forum) said that we should be seeing some unveilings this year.
I know that the whole "Turner news" kind of took the spotlight and I thought I may have missed some Split-Pivot info.
Just curious.
Thanks!
Didn't realize that was still going on. (?)
Based on DW's posts (either here or on another forum) just expected it this fall.
Based on DW's posts (either here or on another forum) just expected it this fall.
Don't even know that myself! (?)
But, thanks for the response anyway.
Hope that things are going well for you and that you're getting the chance to ride a lot over there in Scotland!
Thanks again!
Eric
Bergamont had the Split Pivot only in their Prototypes. The production bikes don't use it. I wonder why??
In my opinion the Split Pivot would be perfect in combination with a hammerschmit! No suspension bob with a perfecly placed pivot point and no bad brakeing habits. Sounds ideal, even better than DW-Link to me.
In my opinion the Split Pivot would be perfect in combination with a hammerschmit! No suspension bob with a perfecly placed pivot point and no bad brakeing habits. Sounds ideal, even better than DW-Link to me.
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And, with the mfr'ing tolerances not needing to be as exact, and with multiple design options, it'd fit the small(er) builders great!
Dude, is it "late 2007, early 2008" already?!
http://www.split-pivot.com/buyit.html
The word "soon" in the bike industry is a huge steaming pile of crap. What really gets me is the rush most vendors are in to update their websites with vaporware, but then how they forget updates when things stall out.
If I remember correctly, the comments were made back in the spring of 2008. Vague, I know, but sometime around then about this fall.
Looks flexy
as a bulldog, you must love to roll around in fresh "soon". you probably eat the stuff too, huh?
Hi all,
I have just read DW's patents; Split Pivot [#2008/0067772 A1] and DW Link [#2006/7128329 B2] and I wonder about 2 things. Thus I'd like to ask DW or anybody who is capable of explaining the following:
1) SplitPivot: Why did DW define an IC of single-pivot suspension as intersection of wheel link and control link (rocker)? Instead of wheel link fixed pivot ....
2) What do you DW consider for 100% anti-squat value ? Squat in 0mm of travel or CoG height over the ground (as it can be seen in motocycle illustrations).
I have just read DW's patents; Split Pivot [#2008/0067772 A1] and DW Link [#2006/7128329 B2] and I wonder about 2 things. Thus I'd like to ask DW or anybody who is capable of explaining the following:
1) SplitPivot: Why did DW define an IC of single-pivot suspension as intersection of wheel link and control link (rocker)? Instead of wheel link fixed pivot ....
2) What do you DW consider for 100% anti-squat value ? Squat in 0mm of travel or CoG height over the ground (as it can be seen in motocycle illustrations).
Here's Figure4 from SplitPivot patent. #15 depicts IC as DW has defined later in the text.
lmao
Looking good, but the arch is backwards.
Main pivot (4) location defines acceleration response, IC location(15) defines braking response.
I don't understand your question, but if you read the dw-link patent 7128329 then you can see an accurate example of anti squat calculation. (and the only published account for a linkage suspension that I'm aware of)
Manitou!
Thanks for your answer.
I've thought that "Instant Center" term is used to describe a point which the rear wheel rotates about at given instant of travel.
I've read DW-Link patent 7128329 B2 two times but maybe todays 6hour ride in freezing wind and more carying bike than riding it may have frozen my concentration. But I didn't find there an explicit definition of how many mm over the lower squat measurement definition line is 100% of squat. I do believe that CoG height defines value of 100% squat, but believe isn't enogh. The squat value in 0mm of travel can't be 100% of squat beacause then you couldn't compare squat curves of two dirrefent linkages with different squat points on squat layout line.
you are thinking about centre of curvature there.
You are right, but probably missing that the rear brake (and essentially the rear wheel) is attached to the seatstays, #2. That's why the IC is #15.
What you talking bout Willis??????
Good question geezer! I have no idea what he's asking either.What you talking bout Willis??????
How is your Czech or Slovak?? My guess is that his english is a LOT beter than what you can do in his language......What you talking bout Willis??????
not saying that I understand exactly what he is asking, but english is obviously not his first language.
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Interesting stuff.Feel free to read the Split Pivot patent applications and make your own assessment by following the links below. You will see for certain that there are specific performance characteristics cited in the applications that have never been implemented or are even capable of being implemented with the FSR design.
US20080067772A1
http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=2&f=G&l=50&co1=AND&d=PG01&s1=Weagle&OS=Weagle&RS=Weagle
US20080073868A1
http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&co1=AND&d=PG01&s1=Weagle&OS=Weagle&RS=Weagle
The reality is that suspension characteristics and performance are directly related to the kinematic layout of the links in said system. Why would I spend my time working to optimize someone else’s design when I could spend the same amount of time optimizing my own. I know that there is a good deal of capability within the Split Pivot design to build bikes that are stronger, lighter, and better performing than some of their counterparts. Like I said earlier though, you need an engineering team with the skill and knowhow to make it happen. I think that you will be happily surprised with the ride of the true Split Pivot bikes when you get a chance to ride one. I wish I could tell you an exact date when that will be, but that’s not something that is in my power.
Dave
I read a fair bit of the patent and couldn't really see anything obvious to explain this;
"there are specific performance characteristics cited in the applications that have never been implemented or are even capable of being implemented with the FSR design.
?
This is also a pretty controversial statement too no ?;
"I know that there is a good deal of capability within the Split Pivot design to build bikes that are stronger, lighter, and better performing than some of their counterparts. Like I said earlier though, you need an engineering team with the skill and knowhow to make it happen."
Are you saying Trek's hasn't got a sufficient engineering team to realise the potential of the split pivot (or ABP as they call it) design ?
I have read about some of these interesting designs and ride the trek. Trek does not mention on any of their bikes or catalogs about a pending patent on their pivot system. So besides all this talk about tuning acceleration and anti squat through pivot locations...how are these pivot systems any different than the Becker patent?
I heard from some of my german friends that went to Eurobike, trek mentioned to them, they have a patent license from someone for the floating shock. Does anyone know if this is what makes the systems different? Or is it really just they are not designing the pivot locations correct? So far I can not tell my bike has a bad ride.
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Well, my english explanation of what I was asking may have been confusing and unclear. But the same I feel about DW's explanation of how to measure and plot squat curve within the three squat conditions.
DW, excuse me for extracting figures/texts from your patent 7,128,329 B2.
The 1st figure, Figure 1a from pat. file, clearly shows how the squat force vector is constructed and how it is used to find a squat point 10 on a squat layout line 11. The percent of current squat is defined as distance of squat point 10 from the lower squat measurement line 12 (distance 13). There are 3 squat conditions defined. Anti-squat: if squat point 10 lies anywhere on the squat layout line 11 ABOVE the lower squat line 12. Zero-squat: if squat point 10 lies directly on the lower squat measurement line 12. Pro-squat: if squat point lies BELOWE the lower squat measurmnt line, it is graphed as negative percentage.
When I measure the vertical distance of squat point above the lower squat line in milimeters, how do I know how many percent of total squat it is ? Or otherway, how many milimeters above lower squat line define 100% squat ?
The 2nd figure, Figure 3 from pat. file, shows an example of plotted squat curve. Percentage of suspension travel is clear. But percentage of squat isn't clear for me. Does it mean that squat point distance, in milimeters, over lower squat line in 0mm of travel define the 100% of squat ? I doubt because then you couldn't compare two different linkages with different squat amounts although they would have the same squat curve.
The 3rd image is an illustration from Tony Foale's book; sorry for copyright breaking. It shows that he used sprung mass CoG height over the lower squat line as definition of 100% squat value in milimeters. Are you DW using another definition of 100% squat?
DW, excuse me for extracting figures/texts from your patent 7,128,329 B2.
The 1st figure, Figure 1a from pat. file, clearly shows how the squat force vector is constructed and how it is used to find a squat point 10 on a squat layout line 11. The percent of current squat is defined as distance of squat point 10 from the lower squat measurement line 12 (distance 13). There are 3 squat conditions defined. Anti-squat: if squat point 10 lies anywhere on the squat layout line 11 ABOVE the lower squat line 12. Zero-squat: if squat point 10 lies directly on the lower squat measurement line 12. Pro-squat: if squat point lies BELOWE the lower squat measurmnt line, it is graphed as negative percentage.
When I measure the vertical distance of squat point above the lower squat line in milimeters, how do I know how many percent of total squat it is ? Or otherway, how many milimeters above lower squat line define 100% squat ?
The 2nd figure, Figure 3 from pat. file, shows an example of plotted squat curve. Percentage of suspension travel is clear. But percentage of squat isn't clear for me. Does it mean that squat point distance, in milimeters, over lower squat line in 0mm of travel define the 100% of squat ? I doubt because then you couldn't compare two different linkages with different squat amounts although they would have the same squat curve.
The 3rd image is an illustration from Tony Foale's book; sorry for copyright breaking. It shows that he used sprung mass CoG height over the lower squat line as definition of 100% squat value in milimeters. Are you DW using another definition of 100% squat?
oster_oops:
Easy Kemo Sabe my my above post was made with my tounge firmly planted un my cheek
i'll try to explain it, but i will probably end up making you more confused. 
percentage anti squat is the ratio of the total force resisting the suspension compressing under acceleration to the compressive force on the suspension from the mass transfer due to acceleration of the vehicle.
the total force resisting compression would be the resultant forces that come from the driving force form the tire acting on the rear axle, chain force on the rear axle, and the suspension force on the rear axle from the suspension compressing.
so if the anti squat force (vector) is equal and oppsite to the compressive force due to acceleration, then it would be 100%, if it's less, then it would be less then 100%. if the squat force from the suspension doesn't appose the forces on the suspension due to the mass transfer, and actually acts together with it in the same direction, then it is pro squat.
what dw is talking about is how the value of anit squat varies through the suspension travel. you have to keep in mind that with single pivots, the anti squat value is pretty much constant, so maybe thats where the confusion is coming from?
clear as mud?
percentage anti squat is the ratio of the total force resisting the suspension compressing under acceleration to the compressive force on the suspension from the mass transfer due to acceleration of the vehicle.
the total force resisting compression would be the resultant forces that come from the driving force form the tire acting on the rear axle, chain force on the rear axle, and the suspension force on the rear axle from the suspension compressing.
so if the anti squat force (vector) is equal and oppsite to the compressive force due to acceleration, then it would be 100%, if it's less, then it would be less then 100%. if the squat force from the suspension doesn't appose the forces on the suspension due to the mass transfer, and actually acts together with it in the same direction, then it is pro squat.
what dw is talking about is how the value of anit squat varies through the suspension travel. you have to keep in mind that with single pivots, the anti squat value is pretty much constant, so maybe thats where the confusion is coming from?
clear as mud?
Tony Foale and I are in 100% agreement on the measurement of 100% anti-squat. I have discussed this with him in person, face to face, and his latest book includes some of the graphical information that we talked about.
I think you are missing something, but sorry, I am leaving for a long trip and I don't have the time to get into it. Maybe in a few weeks when I get back..
Easy Kemo Sabe my my above post was made with my tounge firmly planted un my cheek
No worries, it sounds like he is trying to get some answers to some interesting questions....some stuff that I would interested in a more clear explination. Just did not him to get the ocassional RM grammar harrasment due to the language issue....