Satchell Link Help

ok ive always wanted to learn more about suspension setups. i have several books on suspension/chassis design that were recommended to me. i haven't really gone through them much yet. just thumbed through, and looked at certain pages..

anyways, i plan on doing a full frame build for my luv now.. decided i want to be able to rip through curves if wanted.. i am choosing to go with a satchell link.. i found some info on them, but i dont understand all of the terminology yet. so heres what i have came up with.

28" uppers pointed down 1°
30" lowers pointed up 3°

heres pics.. hopefully it explains everything.

and as long as i read this right.. "for 100% antisquat the intersection of your arms (in side view) needs to lie on the antisquat line. above it you have over 100% antisquat."

that means anywhere on my antisquat line correct?

setup like it is i think my lower bars will only have 22° angle.

if i want 35° the lowers will be 22.80"
if i want 45° the lowers will be 17.25"

opinions? did i **** something up yet? how can i improve this?






now since i will probably have to be running somewhere between 17-22" long lowers, should i shorten the uppers to the same length so i dont have camber change? i dont know how much all that will affect it since its not going to be bagged.

Have you messed around with any of the calculators?
You would want to use the one at the top of the first post in this link.
http://www.pirate4x4.com/forum/showthread.php?p=2269127#post2269127
To the best of my knowledge you can get away with very short arms on a Satchel link. I would try to keep those arms as close to 45* as possible. The angle of the arms will have an affect on roll steer.

i dont have excel.. can i just download a viewer to use it?

Try this
http://mysite.verizon.net/triaged/4linkcalcv15html/index.html
Only problem I see with that is you have no way to save it for adjusting the inputs.

You could DL open office but it's a big program.

downloaded a viewer. i can open the file now, but cant change the numbers

my new computer should be here the 31st and IIRC i bought it with microsoft word etc.

damnt.. i really wanna use that calculator!

hmm. ill download open office.

Some fool on the old site has a satchell link in his project thread. I hear he's really lazy, likes to procrastinate, and not real savvy w/ computer internet stuff, so you might not see his thread uploaded to this site for a long time.

For the lower links:
--As close to 45 degrees in plan view is what Terry Satchel recommends. Either side of 45 degrees will put more loads on your bar ends and mounting brackets. I wouldn't be comfortable w/ that shallow of a converging angle in your design to keep the axle laterally located. I hear that 38-45 degrees is what you are looking for w/ the bars in plan view.
--You have the bar ends angled in relation to the bar. This will just further increase the loads on the end bushings and tabs, which will be more likely to cause bind. Get the end bushings perpendicular to the bars. You will find the angled lowers do not have much torsional rotation during articulation. It's the upper bars that will be effected more and show signs of binding WAY before the lowers.

Triaged's calculators help me greatly, I highly recommend using it for your design.

Feel free to bounce some of your ideas around. I would be happy to contribute.

thanks for the reply! and i was wondering about how i had the bar ends angled. i mainly drew it up for ease, and because its just a drawing. but thanks for the tips on that.

38° gives me a 18.5" long bar
and to have a matching upper, the bar will be 14".

i just downloaded open office. so hopefully that will work for me, and ill be back with some better info!

Yep. The more you angle the lowers, the shorter the bar gets to retain that 38-45 degrees.. You can get a sharper angle and more bar length by locating the bar mount on the axle as close to the wheel as possible (outboard of the frame), if your design allows it. My lowers actually set inside the rim a little bit. Of course I had this same dilemma you speak of in my design. You keep shortening your bars... you gonna start getting some nasty roll steer numbers OR you are gonna sacrifice a consistent anti-squat thru travel...... decisions-decisions......

yeah i pushed the lowers out as far as i could to the tires.. at first i was trying to make it work with current frame which of meant everything couldnt be wider than 28".

well i entered some numbers into the calculator. going off my drawing i had lower bars 38° which made them 18.5. so i figured upper would be 14. but in the calculator, i had to lengthen the uppers to 18.5 as well so they were the same length in side view..

heres a print screen.


ignore vehicle weight/unsprung front and rear weight.. i have no idea on those

If you change one of the 23.5" dimensions to 23.6" or 23.4", you'll get to see your roll center migration during travel.
I believe if you change one of your "axle end" points to a factor other than 0 you'll get to see the pinion rotation.
You can determine how much roll steer you're getting by comparing the difference of the travel roll axis from ride height to bump or droop.
Yep... your unsprung mass is way off.... which effects what the anti-squat readings reflect in this calc. If I was to guess... I'd say 300 front and 400 rear... which is still probably too high for your rig.... but should get you closer.

changed a coupe things as you said.



180° pinion change??

Now click on the [BUMP] button.... it will show what happend to the geometry when the suspension was compressed and inch. Compare those numbers to the ride height numbers....  this will tell you your amounts of change.

 FYI: I suspect your roll steer numbers will be fairly drastic and therefore noticable while driving when the suspension articulates.

i click the buttons and they do nothing..

You probably need to enable your macros when you start the program. It usually prompts you to do this before the spreadsheet opens.

i went to Tools>Macros>Run Macro... then clicked the + sign by my file name then there is 14 different ones to choose from. ranging from sheet# module# etc

tried several of them, and they dont make it move

This might be an Excel issue.... in which case, I'm retarded.

Try closing excel and reopening it and see if you are prompted to enable anything when you go to open the calculator.
I have an old version and new version of Excel on 2 different computers and it enables the macros differently... maybe it has something to do w/ security settings??? Dunno?

Seeing how your geometry reacts to movement/travel is the best way to see if your design is acceptable. That's the main reason Triaged's calculator is such a great tool. The hard part is knowing what all the #s mean and what ranges you want to fall within. Then you start getting into personal preferences & making compromises.
decisions-decisions

well im using open office.

I'll try running the numbers later today for you. I have the calc and it seems to work fine for me. Maybe something didn't DL right.

cool man, i appreciate that!