# Interesting observation of mine regarding full suspension nomenclature-



## Marc (Jul 10, 2008)

When you hear someone refer to a Horst link four bar... or non Horst four bar (faux bar sometimes)....


All of those designs are technically a five bar linkage.  I wonder how many mechanical engineers who design or ride these things notice that.  Kinda funny when you think about how long it's been wrong...


----------



## bvibert (Jul 10, 2008)

Any pictures or diagrams of said design to illustrate your point?


----------



## Marc (Jul 10, 2008)

Actually, if you want to get even more technical, they're actually six bar slider linkages.  With one degree of freedom.


----------



## Marc (Jul 10, 2008)

bvibert said:


> Any pictures or diagrams of said design to illustrate your point?



Ok... kind of.

Here's one from Turner's website-







So you have what's usually called the rocker as one link, the shock is actually two links coupled by a sliding joint rather than a pivoting joint, the front triangle is one link, the chain stay is one link, and the seat stay is one link.

1 + 2 + 1 + 1 + 1 = 6.


----------



## MRGisevil (Jul 10, 2008)

Your mom's a horst link four bar


----------



## bvibert (Jul 10, 2008)

MRGisevil said:


> Your mom's a horst link four bar



:lol:


----------



## Greg (Jul 10, 2008)

Marc is an alien. That is all.


----------



## Marc (Jul 10, 2008)

MRGisevil said:


> Your mom's a horst link four bar



I actually expected this kind of response for an architect, since all you can manage to design is a 3 bar linkage, otherwise known as a truss.


----------



## bvibert (Jul 10, 2008)

Marc said:


> Ok... kind of.
> 
> Here's one from Turner's website-
> 
> ...



You win, I guess.


----------



## Marc (Jul 10, 2008)

I'm just saying.... four bar isn't accurate.  It would make as much sense as going around calling a truss on a bridge a four bar linkage.


----------



## MRGisevil (Jul 10, 2008)

Marc said:


> I actually expected this kind of response for an architect, since all you can manage to design is a 3 bar linkage, otherwise known as a truss.



Might only be a 3 bar linkage, but you can bet your nomenclaturing ass it'll be a LEED silver linkage, at the minimum. I'll even shave half a point off energy and atmoshphere by utilizing recyclable links.


----------



## bvibert (Jul 10, 2008)

Marc said:


> I'm just saying.... four bar isn't accurate.  It would make as much sense as going around calling a truss on a bridge a four bar linkage.



It's not all that different from what is considered a 4 bar suspension in the automotive world though.  They don't count the car/truck chassis as a link like you're doing with the front triangle.


----------



## Marc (Jul 10, 2008)

bvibert said:


> It's not all that different from what is considered a 4 bar suspension in the automotive world though.  They don't count the car/truck chassis as a link like you're doing with the front triangle.



Depends on what type of suspension design you're talking about.  Double wishbone suspension-






This is technically also a six bar slider, but it's reduntant.  Take away the shock and spring, and you're left with a four bar linkage that will track the same.  It just wouldn't function very well.

The car chassis in this case, and the front triangle to a lesser degree would probably be considered (by any competent mechanical engineer) to be designated the ground link, but it is a link nonetheless.  One of the characteristics of linkages is you can designate any one link as the ground link and the thing will still create the same motion.

It's arguable, though, whether the front triangle is really a "ground" link since it moves an awful lot with respect to ground.... however, it is a as much a link as any other in that design.


----------



## Marc (Jul 10, 2008)

And actually, you're right about the similarity to a bike design.  It is the same design, but the shock is on the opposite side on a bike, to get the leveraged travel advantage which isn't necessary on a car.  Saying it's reduntant isn't really right.  The slider does affect the motion in that it limits travel.  So it is necessary.  It can be simplified at the sacrifice of functionality though.


----------



## bvibert (Jul 10, 2008)

An example of a rear 4 link suspension (no shocks/springs shown):

http://www.youtube.com/watch?v=E6s88d2FbPE

Similar in number of linkages, except the axle on a bike stays (thankfully) parallel to the frame (front triangle).  My point is there's still as many links by your definition, yet it's still called a 4 link.  I'm not saying you're wrong, rather pointing out that it's not necessarily just the bike industry that's been in error all these years.


----------



## Marc (Jul 10, 2008)

bvibert said:


> An example of a rear 4 link suspension (no shocks/springs shown):
> 
> http://www.youtube.com/watch?v=E6s88d2FbPE
> 
> Similar in number of linkages, except the axle on a bike stays (thankfully) parallel to the frame (front triangle).  My point is there's still as many links by your definition, yet it's still called a 4 link.  I'm not saying you're wrong, rather pointing out that it's not necessarily just the bike industry that's been in error all these years.



Can't watch yt at work.

They are in error, most definitely.  They just dumbed it down for consumers, that's all.


----------



## Greg (Jul 10, 2008)




----------



## bvibert (Jul 10, 2008)

Don't worry, it's a stupid animation anyway.

4 bar sounds much better than 6 bar slider.


----------



## bvibert (Jul 10, 2008)

Greg said:


>



This is some serious work here, don't douche up our thread... :roll:










()


----------



## Marc (Jul 10, 2008)

bvibert said:


> This is some serious work here, don't douche up our thread... :roll:
> 
> 
> 
> ...



Cereal, this is important stuff.


----------



## cbcbd (Jul 10, 2008)

This is my favorite kind of suspension


----------



## mondeo (Jul 10, 2008)

bvibert said:


> An example of a rear 4 link suspension (no shocks/springs shown):
> 
> http://www.youtube.com/watch?v=E6s88d2FbPE
> 
> Similar in number of linkages, except the axle on a bike stays (thankfully) parallel to the frame (front triangle).  My point is there's still as many links by your definition, yet it's still called a 4 link.  I'm not saying you're wrong, rather pointing out that it's not necessarily just the bike industry that's been in error all these years.



You're right, it isn't just the bike industry.

Although I think it might be 4 links per wheel...damn live rear axle. Bump steering all over the place.


----------

