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4link calc

carslut

perfection in plasma
Joined
May 19, 2020
Member Number
164
Messages
11
Location
Fallbrook Ca
ran down into the dumpster fire long enough to grab some help locking in a 4link I'm working on and ........... dead. anyone have the latest version of the 4link calculator they would be willing to pass along?
 

vetteboy79

It's bent. #ttb
Joined
May 19, 2020
Member Number
305
Messages
456
Location
Morganville, NJ
Patooyee was nice enough to host them on his server:

http://www.patooyee.com/linkcalc/3_LinkV1.0b.xls

http://www.patooyee.com/linkcalc/4BarLinkV3.0c.xls

http://www.patooyee.com/linkcalc/4BarLinkV3.1d.xls

The last one is the latest publicly available version, where I added the 'travel' window and replaced the need for the 'solver add-in' with straight vector math so you don't need anything special to view it in Excel or OpenOffice. Depending on macro settings the buttons for travel might not work but you can put a number directly into the 'travel amount' box (positive for bump, negative for droop) and view the same thing.

edit: hey Austin , Pat's had these hosted on his private server since 2014, is there a way to upload directly to here?
 
Last edited:

OC IH

Old & Broken
Joined
Jun 7, 2020
Member Number
1889
Messages
10
I asked this on another forum and didn’t get any answers. Its sad when a good thing comes to an end.

Hopefully someone here can help. Any feedback would be appreciated. Since I asked the question below the front is complete and I dropped the front design into the calculator to have the data there to start on the rear. We’re turning around the Scout to start on the rear four link tonight. I’m getting a lot of “#DIV/0!” and “#VALUE!” calculations by having the upper and lower links set to the same points.

Question for anyone.

How do you set up Version 4.0 for radius arms? With the old version I used I recall it had a note to set the upper and lower links with the same frame end point and the axle end at the center of the axle tube. I can’t find any of the data from my old build and can’t find where I might have gotten that idea.

We’re almost done building the front radius arms and will hopefully start on the rear four link this week for our Scout 800. We want to play with some numbers.
 

vetteboy79

It's bent. #ttb
Joined
May 19, 2020
Member Number
305
Messages
456
Location
Morganville, NJ
How do you set up Version 4.0 for radius arms? With the old version I used I recall it had a note to set the upper and lower links with the same frame end point and the axle end at the center of the axle tube. I can’t find any of the data from my old build and can’t find where I might have gotten that idea.

If putting the same frame end point gives errors, just make them close, like .1 off. That difference won't matter. The axle end shouldn't matter much either as it's using the instant center for the calculations and with radius arms the instant center is always at the same place regardless of the link placement on the axle. If the antisquat/dive values look big, they should, because radius arms have terrible characteristics like that.
 

OC IH

Old & Broken
Joined
Jun 7, 2020
Member Number
1889
Messages
10
If putting the same frame end point gives errors, just make them close, like .1 off. That difference won't matter. The axle end shouldn't matter much either as it's using the instant center for the calculations and with radius arms the instant center is always at the same place regardless of the link placement on the axle. If the antisquat/dive values look big, they should, because radius arms have terrible characteristics like that.

Thanks. I'll mess with the frame end points and see what happens. Both antilift and antidive values are negative at ride height at the moment and returning errors for all other positions. We'll see what happens when we get real numbers in for the rear as we begin to see what is possible.
 

Treefrog

Book Wheeler
Joined
Jun 11, 2020
Member Number
1958
Messages
201
Location
Central Florida
How do you set up Version 4.0 for radius arms? With the old version I used I recall it had a note to set the upper and lower links with the same frame end point and the axle end at the center of the axle tube. I can’t find any of the data from my old build and can’t find where I might have gotten that idea.

The likely cause is that you are using the same point for both links on the axle. That causes issues with determining how the axle pivots as it travels. The same point should be used on the frame.

Edit: Looking into it a bit more, there are some calculations errors that occur if the lower and or upper links on one end of a vehicle are parallel, but that is accounted for already, and is not an issue. There is a possible issue with the pinion angle changes, resulting from me forgetting how the arc-tangent function works. So use common sense if the value appears 100*+ off of what seems reasonable, when using the file you have. I have fixed the pinion angle calculations and updated the file in the link above.
 
Last edited:

Austin

Blame Canada
Joined
May 1, 2020
Member Number
1
Messages
1,850
Location
St.Louis, MO.
Patooyee was nice enough to host them on his server:

http://www.patooyee.com/linkcalc/3_LinkV1.0b.xls

http://www.patooyee.com/linkcalc/4BarLinkV3.0c.xls

http://www.patooyee.com/linkcalc/4BarLinkV3.1d.xls

The last one is the latest publicly available version, where I added the 'travel' window and replaced the need for the 'solver add-in' with straight vector math so you don't need anything special to view it in Excel or OpenOffice. Depending on macro settings the buttons for travel might not work but you can put a number directly into the 'travel amount' box (positive for bump, negative for droop) and view the same thing.

edit: hey Austin , Pat's had these hosted on his private server since 2014, is there a way to upload directly to here?

Not sure how I missed this. I can probably make a page for all this type stuff.
 

OC IH

Old & Broken
Joined
Jun 7, 2020
Member Number
1889
Messages
10
We used 4 Bar Linkage Calculator v4.1 for this. I would appreciate some feedback on what the calculator is giving me. This is for a Scout 800, radius arm front, and 4 link rear. The front is done. We’re working on the rear.
The calculations show the longest links possible. Things that can change are;
  • Upper Link Axle end can move forward up to 2 inches.
  • Upper Link Frame end can move down 1 or 2 inches (adjustable bracket).
  • Lower Link Axle end can drop up to 2 inches.
  • FRAME ENDS can get up to 9 inches shorter.
The biggest changes in the calculator come from shortening the links. This increases anti-squat, anti-lift, and roll axis in the rear.
This is the first time we’ve set up a rear four link. Any feedback is appreciated. We want to get the numbers as good as possible before we start cutting new steel.
Scout 800 20200627 Link Calculator Long & High Points.jpg
 

Austin

Blame Canada
Joined
May 1, 2020
Member Number
1
Messages
1,850
Location
St.Louis, MO.
I've been looking at this and thinking about it. Would this be something that would be beneficial to have an a built in calculator on here? I could see it being somewhat of an attraction to the site ... but would that make it a PIA or is it preferred to run in Excel?
 

Treefrog

Book Wheeler
Joined
Jun 11, 2020
Member Number
1958
Messages
201
Location
Central Florida
I've been looking at this and thinking about it. Would this be something that would be beneficial to have an a built in calculator on here? I could see it being somewhat of an attraction to the site ... but would that make it a PIA or is it preferred to run in Excel?

I would think that Excel is preferred. That way it can be improved by the community without having to worry about how it gets updated. Keeping it in Excel also makes it easier to keep track of multiple setups, for example if you are helping a buddy with his rig. And the current version (4.1) has a page, materials, that allows users to add to a personal database. When playing around with it in Excel, I would often create design specific outputs or have outputs normally not shown presented to me.

The best approach may be a resources page that has the files or link to threads about the files so that you don't have to dig around to find them. Having the thread links may be the best way because it will make feedback and discussion about a particular calculator easier to follow, at least until the inevitable change into a check my numbers thread. File uploading, at least for Excel docs, would help with the issue that started this thread, namely dead and broken links to where they are stored.
 

Austin

Blame Canada
Joined
May 1, 2020
Member Number
1
Messages
1,850
Location
St.Louis, MO.
I would think that Excel is preferred. That way it can be improved by the community without having to worry about how it gets updated. Keeping it in Excel also makes it easier to keep track of multiple setups, for example if you are helping a buddy with his rig. And the current version (4.1) has a page, materials, that allows users to add to a personal database. When playing around with it in Excel, I would often create design specific outputs or have outputs normally not shown presented to me.

The best approach may be a resources page that has the files or link to threads about the files so that you don't have to dig around to find them. Having the thread links may be the best way because it will make feedback and discussion about a particular calculator easier to follow, at least until the inevitable change into a check my numbers thread. File uploading, at least for Excel docs, would help with the issue that started this thread, namely dead and broken links to where they are stored.

I hear ya. I was planning on having a public/private setting where you could share your results with others.

I totally get having it improved by the community. Who keeps it in check? From breaking and giving bad data?
 

desertPOS

Red Skull Member
Joined
Jul 2, 2020
Member Number
2236
Messages
73
Version 4 is bad ass - I've been using V3 like a chump:homer:
 

Treefrog

Book Wheeler
Joined
Jun 11, 2020
Member Number
1958
Messages
201
Location
Central Florida
I hear ya. I was planning on having a public/private setting where you could share your results with others.

I totally get having it improved by the community. Who keeps it in check? From breaking and giving bad data?

What sort of public/private setting are you thinking? Namely, what would public look like?

The community has to keep it in check; it is no different than the old board threads on designing suspension or choosing springs. The threads on the calculator help. It is also not a thing that many people dig into and edit; as far as I can tell only 4 people have made new versions. And from playing with it, it is usually obvious if something isn't right.

A good middle ground may be to have both a built in and excel version. The built in lags behind some while an update is getting vetted.
 

Austin

Blame Canada
Joined
May 1, 2020
Member Number
1
Messages
1,850
Location
St.Louis, MO.
What sort of public/private setting are you thinking? Namely, what would public look like?

Basically it's sharable or not sharable. Once you start designing and save it you'd have your own URL for it. You can share it or not, maybe even add it to a list of shared Calcs with a link to your rig so people can see them all? Just spit-balling here.....

vetteboy79 - are you the keeper of the calc now? I just emailed the guy whose email is in the calc.


I made a new link for this kinda stuff in the main nav called Resources. If you need something added/updated just shoot me a PM
 

Treefrog

Book Wheeler
Joined
Jun 11, 2020
Member Number
1958
Messages
201
Location
Central Florida
Why are the travel AS numbers so far off from previous versions?

Think I figured it out. Versions 4.0 through 5.2 do not account for the motion of the wheel relative to the body during travel. I caught it while doing version 5.3, which I put out a few days ago. 5.3 should be more accurate than V3.1, which I believe you are using.
 
Joined
Oct 14, 2020
Member Number
2940
Messages
6
Think I figured it out. Versions 4.0 through 5.2 do not account for the motion of the wheel relative to the body during travel. I caught it while doing version 5.3, which I put out a few days ago. 5.3 should be more accurate than V3.1, which I believe you are using.

I was looking at version 4.1 compared to anything less than 3.1.
Got a link to said V5.3?
 
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