Many trail bikes with 130 or 140 mm rear travel use single pivot designs like:

https://www.pinkbike.com/news/calibre-bossnut-v2-review.html
“…a single-pivot design with the main pivot located just above the bottom bracket, a secondary link is found above the rear wheel axle on the seat stay, which is connected directly to the shock. There is a small link mounted to the seat tube that should increase stiffness and keep everything in line as the suspension cycles up and down…”
in action:
https://www.pinkbike.com/video/476084/

Cotic calls it “DropLink suspension”?
Other bikes, very similar design:
Spezialized Epic
YT Jeffsy
Calibre Bossnut
Polygon Siskiu T
or or or

Who came up with this typ of design (Specialized?)?
Was it patent protected before and now the design is spreading in the trail bike segment?

Various designs were patented not long after the safety bicycle was invented – for example:

I thought Single Pivot was like an Orange five?

Isn’t the one in the link a quad link design with 4 sets of bearings?

That pic’s technically a URT – but it was more an example to show that suspension frames have been around almost as long as the bicycle itself. If I get bored at work, I’ll look through my library and find a single-pivot.

This “Epic” or “Jeffsy” or “Droplink” Design

https://www.pinkbike.com/video/476084/

appears to be very simple and still possible to “tune” the damper progression in an easy way: the small, black link (seat stay mounted, close to damper) in above video transfers “at the end of stroke” much more wheel travel suspension velocity to the damper. And thus stiff increase in force for “higher bumps”/ close to end stroke.

The design referred to is a single pivot as the only thing controlling the arc of the rear wheel is that lower arm. However, the shock is controlled via a further linkage – so it’s classed as a single pivot with linkage controlled shock.

This is different to what most people probably think of as a single pivot – like the Orange fs design and the old Marina from the late 90’s.

The YT Jeffsy isn’t a single pivot design like the Cotic or Bossnut as the pivot is in the chainstay and not the seatstay, as were the early Epics. Hence it is a 4 link suspension design.

It’s another variation on Linkage activated single pivot, or back when everyone was being a snob “faux bar”…

The main advantage over a simpler single pivot like an orange is that the shock linkage can be used to change compression ratio/progression through the stroke…

The design referred to is a single pivot as the only thing controlling the arc of the rear wheel is that lower arm. However, the shock is controlled via a further linkage – so it’s classed as a single pivot with linkage controlled shock.

Excellent explanation. Things get much clearer now to me!

Old, very complex designs: they tried to make the rear wheel move nearly “vertically” and not on an arc (which is very difficult to do).
This above single pivot + further shock linkage design appears to me very simple and very straight forward to make good use out of the shock. There are many other design goals for a rear suspension. But apparently not too difficult to design a modern 130 or 140 mm trail bike suspension?

4 bar suspension has been around yonks (Specialised FSR originally I think) and also works well to be fair. Loads of bikes now use that sort of suspension. There are also some less common ones that work well – the DW link design which Evil use, and a number of other more boutique bike companies.

Who came up with this typ of design (Specialized?)?
Was it patent protected before and now the design is spreading in the trail bike segment?

Specialized owned the Horst link aka four bar patent in the US, which has now expired. This precluded most US bike designers using it, and a lot of Europeans steered clear of it as well. Now that the patent has expired a lot of players are moving to a variation of it.
Your initial list as mentioned above was a combination of four bar designs(Epic, Jeffsy) and linkage actuated single pivots e.g. Boss nut, Cotic.

As far as I’m concerned though, most modern platforms work fine for me within my limitations – Vpp, dw, 4 bar, faux bar, all pretty much the same to me.

Isn’t the epic still a Horst link, due to engineered flex in the stays?

I’m sure I’ve seen some older bike with it – but my brain can’t get past AMP or Manitou’s.

Isn’t the epic still a Horst link, due to engineered flex in the stays?

I’d say it’s closer to a linkage driven single pivot as the flex is most likely to be around the axle, rather than in the chain stay.

Older FSR was close.

IIRC there were all sorts of designs floating around, many of which were single pivot effectively. Remember the Manitou one, with forks as seat stays?

Older FSR was close

Looking first at this picture: “hell no that’s different”

But then thinking about the kinematics: you are right! This bike totally looks different – compared for example with the DropLink from Cotic. But what it makes look so different is only the frame – the “cut” seat stay. The kinematics is indeed very similar!
Difference in performance / ride: the damper then?! Kinematics was o.k. but the damper technology wasn’t there?

Found below in an “MBR” interview with David Earle, independent design consultant, Sotto Design:

Single pivot: limited control of shock and wheel parameters.
Single pivot with shock linkage: high control of shock parameters, limited control of wheel parameters.
Linkage: high control of shock and wheel parameters

.

As discussed above the suspension type spreading for trail bikes (this type: https://www.pinkbike.com/video/476084/ ) – single pivot with shock linkage – makes good use out of the shock (progession and similar).
Due to the single pivot nature wheel travel is “arc” shaped. No or limited control there.
At the same time this single pivot + shock linkage design is still rugged and simple plus for 130 mm or 140 mm travel bikes the “arc” issue might be not as critical (as compared for Enduro 160 mm bikes or so?).

Santa Cruz Superlight is a single pivot set up.

was never quite sure what was going on at the back of my Tomac Eli, but it was a great riding bike. Still single pivot but some funky shock actuation too. Looked like a plumber’s spasm though.

Died as did many ABG-welded frames riddled with cracks.

Good article on suspension designs here…..

http://www.bikeradar.com/mtb/gear/article/ultimate-guide-to-mountain-bike-rear-suspension-systems-50849/

Didn’t the older Cove and Kona FS’s (~early 2000s) utilise single pivot linkage activated designs?
They had the pivots on the seat stays rather than the chain stays which distinguished them from the horst link set ups.

was never quite sure what was going on at the back of my Tomac Eli, but it was a great riding bike. Still single pivot but some funky shock actuation too. Looked like a plumber’s spasm though.

That’s great!
And the engineer was sooooo proud engineering this “plumber spasm”. He got lost in the dark art of linkage design…
😯

Good article on suspension designs here…..

http://www.bikeradar.com/mtb/gear/article/ultimate-guide-to-mountain-bike-rear-suspension-systems-50849/

this is a good one!
Thanks!!!

I always liked how much can be done with a complex single pivot. Like, my GT Idrive was a single pivot with extra madness hanging off the bottom. And my Last Herb DH was a single pivot but with mad linkage action that meant it was super soft and linear at the start then progressed massively to rising rate as it compressed- it was so reactive off the top it felt like it had a flat tyre, pretty cool but also really pretty odd.

And now my Remedy 29 is a single pivot too, sort of, since it’s got a concentric rear axle pivot. Throw in a floating shock with clever racecar superdamping and you get something that rides totally unlike my old orange

tomhoward – Member

Isn’t the epic still a Horst link, due to engineered flex in the stays?

TBH it’s not really either, flex stays are a whole other thing. (it’s specifically not a horst link because the definition of that is all about chainstay pivot placement, and it doesn’t have one)

IIRC, the Horst link was originally developed for motorbikes. I’m not big on motorbikes, but I think they generally (maybe always?) use a single-pivot rear suspension. I would bet money that motorbike designers have looked at every arrangement of linkage driven shocks they can imagine, so I think the answer to the OP’s question is probably motorbike designers.

If you remember the Giant NRS suspension (which preceded the current Maestro design), it was supposedly developed by Renault Sport F1 engineers, although I have a feeling that that was more of a marketing ploy than anything. Anyway, the result was basically a variation on the Horst link, so Specialized sued and won, although Giant claimed it was a different design because the rear chainstay pivot was much lower.

Problem with the NRS design was that it was intended to be run with zero sag, so was harsh riding – Maesto was a big improvement. NRS was ok for XC bikes, but would have sucked for longer travel bikes, so Giant used single-pivot designs for their other bikes. Irony was that Giant claimed they commissioned F1 engineers to develop a new suspension design, but ended up reinventing a worse version of the Horst link. I always wondered if they managed to get a refund from Renault Sport.

I’m sure single pivot full suspension on bicycles has been introduced lots of times. The first times that I remember it being used on mainstream bikes was on that terrible Trek full sus thing. Then there was the Verlicchi made frame which was rebadged and used by loads of companies and ridden by the likes of Steve Peat and Dave Cullinan. Best of them all was the awesome Mountain Cycle San Andreas with upside down front forks and massive pro-stop discs all round.

Think four bar was first developed by Mert Lawill on the Fisher RS1, and later adapted by Horst Leitner with the Horst link and used on AMP bikes and Turners. Specialized bought the Horst link patent and Turner had to pay them royalties even though he helped to develop it.

You only realise what a good idea the Horst Link was when you see the huge amount of brake interaction on a Lawill design unless it has a floating brake mount.

Trek’s ABP and Weagle’s Split Pivot is very nice in that they can brake like a four bar but pedal like a single pivot.

Best of them all was the awesome Mountain Cycle San Andreas

checked this bike:
http://www.cycleexif.com/mountain-cycle-san-andreas

This is fantastic! This was roughly 25 years ago?

The new, simple trail bike stuff like:
https://www.pinkbike.com/video/476084/
looks soooo much more rugged and logical!

the Mountain Cycle ‘San Andreas’ hit the mountain bike world like an UFO

Can imagine.

That’s not a great example to be honest, way too much modern stuff on it.
Check out this example of what they looked like when they first came out –
http://www.retrobike.co.uk/forum/viewtopic.php?t=184065

hols2 – Member

IIRC, the Horst link was originally developed for motorbikes.

I think he started out on motorbikes but the official horst link was first for mountain bikes. Of course, it’s just a totally bogstandard 4 bar link repurposed from car suspension, and probably the same design’s been used in millions of other things, steam engine linkages or tractor bars or something.

Of course, it’s just a totally bogstandard 4 bar link repurposed from car suspension

In one sense, yes. But in car suspension, it’s used to control the camber of the tyre and the roll center. The claimed benefits for MTBs are controlling the effect of chain tension and braking forces on the suspension, so it’s implemented quite differently.

>>>chiefgroovy

You only realise what a good idea the Horst Link was when you see the huge amount of brake interaction on a Lawill design unless it has a floating brake mount.

Trek’s ABP and Weagle’s Split Pivot is very nice in that they can brake like a four bar but pedal like a single pivot.
Interesting, I see the Lawill parallelogram design as eliminating brake /suspension interaction in that the bit with the caliper on it doesn’t rotate about the axle as the suspension moves (as it would with a single pivot). But maybe that is not such a good thing.

Who came up with this typ of design (Specialized?)?

specialized specialise in not inventing anything. so i doubt it.

Specialised bought the patent from AMP Research,
Old post about it.

Fisher RS-1 pivoted around the BB in 1990

Oh and is that a disc brake.

single pivot, linkage driven shock, like:

https://www.pinkbike.com/video/476084/

in one of the articels I found an interesting detail:
This sort of linkage also allows to use very short stroke dampers with low oil volume (and low cost). Depends on the linkage lever arm ratio and others. (And at the same time easy to “design a desired progression”.)

For trail bikes: low oil volume dampers no problem. There is enough time for “cooling” the oil.
For Enduro type and downhill type bikes: low oil volume is a problem. Damping characteristics will “creep away” too fast due to heat build up.

Might be an indication why this set up works especially for trail bikes so well. Together with the fact that these suspension have low travel (130 or 140). Small travel: “arc” movement of rear wheel not a big issue.

And: this type of design appears to be easy to build and low cost to manufacture.

( Posts about the HORST link type suspension:
not a “single pivot system”.
See in one post mentioned link:
http://www.bikeradar.com/mtb/gear/article/ultimate-guide-to-mountain-bike-rear-suspension-systems-50849/ )

old, but neat link:

http://ffden-2.phys.uaf.edu/211_fall2010.web.dir/Michael_Stanfill/FourBar.html

The Four-Bar design is a very widely used strategy that allows a large amount of adjustment of spring leverage ratios. The four-bar linkage design was the next step in the evolution of bicycle suspension. It was a lighter, more versatile design that, if built well, is a rock-solid choice for manufacturers. The main idea is the linkages and components represent a four-sided polygon: the chain stay, seat stay, rocker, and seat tube. The design is similar in principal to independent front suspension common in vehicles. There are different versions of this design, and each vary ever so slightly. But, each has their own patent filed with the US Patent Office.

More detailed explanations when following this link.
According to this:

single pivot with linkage driven shock is a special case of “four bar”

HORST link type of suspension is a special case of this “four bar” type as well.

They were all patented at a certain time.
Difference: where the pivot is located near the axle.

others:
According to
http://ffden-2.phys.uaf.edu/211_fall2010.web.dir/Michael_Stanfill/SinglePivot.html

single pivot without linkage driven shock or just “single pivot” is the oldest bike suspension type

True single pivot behind BB with no dropout pivot?

Linkage driven shock?

Recognisable as a “modern” mountain bike?

The “Skinner Descender”

1984

Or the1987 SE Shocker by Hanebrink

Recognisable as a “modern” mountain bike?

Yes!
Fantastic!

In fact – these bikes are very close to modern trail bikes and to suspension types which Cotic calls “DropLink”.

Guess pioneers like Brian Skinner were stuck with very long stroke industrial shocks.

Above pictures, 1984 or 1987 : roughly 30 years ago!!!