[math2014]

Hi all,

I may be mistaken but my eye caught sometime ago a free(ware) linkage/susspension cad-type program is that true? Is there such a thing?

thanks
Yannis

 

[buildyourown]

It only works for 4 bar and it doesn't really tell you anything that you couldn't do yourself with the simplest drafting program
But it's free

http://www.bikeforest.com/CAD/fsCAD.html

 

[math2014]

All i want is to see how the leverage ratio changes in FSR bikes etc...

 

[WheelieMan]

All i want is to see how the leverage ratio changes in FSR bikes etc...

This is what you need:

http://www.mtbcomprador.com/pa/english/downloads.htm

 

[math2014]

thnx bro...usefull site... unfortunately it gives me the same results no matter what dimensions i put in...

 

[WheelieMan]

thnx bro...usefull site... unfortunately it gives me the same results no matter what dimensions i put in...

Huh? What exactly are you trying to figure out?

 

[math2014]

This is what you need:

http://www.mtbcomprador.com/pa/english/downloads.htm

this looks great,

does it work and is virus free?

 

[math2014]

Huh? What exactly are you trying to figure out?

The pattern of leverage ratio on my fsr bike... along with rear wheel travel resulting from using different shocks and linkage plates.

 

[zedro]

unfortunatly it doesnt give out forces (ie. the actual leverage ratios), it only gives displacements and one derivative thereof (relevant for positional damping). Its neat if you want to make quick and rough looks at different bikes where you only have pics, but not all that useful as a design tool or to really analyse/reverse engineer anything.

 

[zedro]

The pattern of leverage ratio on my fsr bike... along with rear wheel travel resulting from using different shocks and linkage plates.

you wont be able to properly design for that if thats what you intend. You'll need CAD

 

[math2014]

unfortunatly it doesnt give out forces (ie. the actual leverage ratios), it only gives displacements and one derivative thereof (relevant for positional damping). Its neat if you want to make quick and rough looks at different bikes where you only have pics, but not all that useful as a design tool or to really analyse/reverse engineer anything.

if i put in the dimensions of my bike for example... and alter shock length and stroke ...will it give me the new resulting travel?

 

[zedro]

if i put in the dimensions of my bike for example... and alter shock length and stroke ...will it give me the new resulting travel?

it wont let you do that because it only takes initial pivot locations of a system. This means you'd have to know all the new coordinates of everything if you changed your shock, ie. it calculates the shock used for a particular static setup, you dont get to tell it what shock it uses. As i said, its not a design tool, it only analyses exact data you put into it.

for that you'd need to create the linkage in a Cad program, then you could make changes and input the new coordinates for every different setup.

 

[math2014]

Cheers zedro... now that i ll go back home for xmas, i ll borrow a cad from a friend and play around a bit

 

[Kornphlake]

Cheers zedro... now that i ll go back home for xmas, i ll borrow a cad from a friend and play around a bit

I know what you meant, but from the wording it sounds like you think a cad is a hand held device to measure stuff or something. Good luck getting that all sorted out, it's going to be a long night.

 

[math2014]

I know what you meant, but from the wording it sounds like you think a cad is a hand held device to measure stuff or something. Good luck getting that all sorted out, it's going to be a long night.

no, i think cad is a design program which some years ago i used to design car susspension systems and airframes, it takes an awfull lot of time to do so, but i really enjoyed it, since it was my hobby .

Alternatively i could go old skool and do it by hand on paper... but i miss my tools here in the UK
:angry:

 

[Brian HCM#1]

Thats a cool site, you can trace your current bike and make it work, its way cool

 

[xy9ine]

The pattern of leverage ratio on my fsr bike... along with rear wheel travel resulting from using different shocks and linkage plates.

thats exactly what i did with my old fsr elite to ghetto-fab some long-travel link plates (many years ago - before the advent of aftermarket kits). i made a simple line drawing in cad based on the points of rotation, then varied the link length to get the desired travel. the net result was surprisingly effective, though the leverage ratio was a bit high.

 

[math2014]

Well according to this linkage program, i can get 150mm of rear travel either by fitting a 7.5 i2i 2" shock or by making a specific plate. hm... the longer shock sounds nice... i wonder if the SX can fit an Avy