- Thread starter
- #21
Yah, I have mock up links, mock up brackets, mock up mock ups......you get the idea.
Final 4 Link Calculations (1 Viewer)
- Thread starter etrnlbzz
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WOW! That's an INSANE amount of detail. One moment while I pick my jaw up off the floor.
Most folks just estimate the CoG on the first pass, by using the top center bolt head on the bellhousing.
That's typically a decent guess, but it's not worth splitting whole numbers of inches over... which is why I brought up the accuracy question.
Out of curiosity, where does your calculated CoG sit relative to that?
Most folks just estimate the CoG on the first pass, by using the top center bolt head on the bellhousing.
That's typically a decent guess, but it's not worth splitting whole numbers of inches over... which is why I brought up the accuracy question.
Out of curiosity, where does your calculated CoG sit relative to that?
couple things...
-my antisquat is in the low 80's
-my upper links triangulate above the top of the pumpkin and point slightly DOWN to the mount inside the frame rails
-my lower links locate at the centerline of the rear axle and point up to under the frame rails...they are 'splayed' to the outer edges of the axle housing.
-all my links are 39" eye to eye
-7075 is a GREAT choice
-my rig on 39's fits in a 7' door
(no hardtop, cage only)
it works great...handles well, drifts well, rides well, climbs well, articulates well, etc. My ONLY complaint is poorly designed mounts under the frame rails....should have made them longer and boxed for improved 'sliding' over rocks. I might also go with all links at 36" eye-to-eye...might...
Remember, there is NO gospel to this...the quick-easy adjustment is to raise the axle point for the upper links...
also remember, steep links are a poor idea and will not climb...a friend had a linked rear suspension put on his CJ and it was totally done wrong...any loose hillclimb and the tires would dig DOWN and not FORWARD...ridiculously poor design with tons of rear steer...but as he put it, "it's kewl to lift a front tire on sharp turns in town!"
-my antisquat is in the low 80's
-my upper links triangulate above the top of the pumpkin and point slightly DOWN to the mount inside the frame rails
-my lower links locate at the centerline of the rear axle and point up to under the frame rails...they are 'splayed' to the outer edges of the axle housing.
-all my links are 39" eye to eye
-7075 is a GREAT choice
-my rig on 39's fits in a 7' door
(no hardtop, cage only)it works great...handles well, drifts well, rides well, climbs well, articulates well, etc. My ONLY complaint is poorly designed mounts under the frame rails....should have made them longer and boxed for improved 'sliding' over rocks. I might also go with all links at 36" eye-to-eye...might...
Remember, there is NO gospel to this...the quick-easy adjustment is to raise the axle point for the upper links...
also remember, steep links are a poor idea and will not climb...a friend had a linked rear suspension put on his CJ and it was totally done wrong...any loose hillclimb and the tires would dig DOWN and not FORWARD...ridiculously poor design with tons of rear steer...but as he put it, "it's kewl to lift a front tire on sharp turns in town!"
Just to add some more here. 7075 t6 is a great material.... on paper. It has a yield strenght that is amazing, meaning that it resists flexing and bending, but it can flex. Then it snaps right back to where it was, this is what makes it best for suspension. These characteristics are what make it great, strong for sliding over rocks and returning to shape. Super stiff and "springy" so you don't lose traction from flex in the suspension. But what most don't realize is that it is brittle, this is the nature of a material that can do what 7075 t6 can. Something like a high modulus graphite fishing rod for a crude example, if that helps.
Point here that I am trying to make is, build it strong enough! It won't bend, it will just crack and break so don't risk it on size. 2.25" + would be my guess, it would be best to calculate the load it can take, so talk to the engineer you know, he could help.
Great stuff, just needs to be engineered to except the sort of loads put on it by your cruiser. I didn't use it on mine, and went with solid 4130 on my rig. I did this because could use a smaller dia. for ground clearance. I new I could trust it to bend first and not just break, even though it has a poor yield by compare. I'm also not worried about damage causing it to fail as I might be with aluminum. I'd have to say if yours get too damaged from bashing, replace them for sure.
Speaking personally about my rig, I may build something else for links later, we'll see how mine hold up. I did calculate the load they could take, and it's right on the line of being just strong enough. You understand, so I could use the smallest dia. for ground clearance possible.
Just my advice
GOOD LUCK!
Also I would think that woody is suggesting the possibility of shorter links just to increase overall triangulation of them? Not sure there.
Point here that I am trying to make is, build it strong enough! It won't bend, it will just crack and break so don't risk it on size. 2.25" + would be my guess, it would be best to calculate the load it can take, so talk to the engineer you know, he could help.
Great stuff, just needs to be engineered to except the sort of loads put on it by your cruiser. I didn't use it on mine, and went with solid 4130 on my rig. I did this because could use a smaller dia. for ground clearance. I new I could trust it to bend first and not just break, even though it has a poor yield by compare. I'm also not worried about damage causing it to fail as I might be with aluminum. I'd have to say if yours get too damaged from bashing, replace them for sure.
Speaking personally about my rig, I may build something else for links later, we'll see how mine hold up. I did calculate the load they could take, and it's right on the line of being just strong enough. You understand, so I could use the smallest dia. for ground clearance possible.
Just my advice
GOOD LUCK!
Also I would think that woody is suggesting the possibility of shorter links just to increase overall triangulation of them? Not sure there.
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actually, my 'shorter link' suggestion is based on measurements from a dozen well-designed buggies that I've studied...but the KEY is the plane in which those links are located...
- Thread starter
- #26
My calculated CoG is.....I'll probably have to take a picture but it's ~1' forward of the bellhousing and just above the crank centerline.
We thought it would be fairly important so we tried to get accuracy on this......and my dad was bored.
We thought it would be fairly important so we tried to get accuracy on this......and my dad was bored.
- Thread starter
- #27
As for the shorter links....I was under the impression that longer links would give it a better overall ride. This is going to be driven to the trails in far far far away lands and I'm going for streetability. Woody, with the calculator (or other means) telling you that with your configuratation you are at ~<85% AS, how does that affect the ride. does ass really drop when you step on it or is it well behaved? Oh, and I like the fact that you can say your FJ40 sitting on 39's "drifts well"
. Thats fricken great.
. Thats fricken great.
mine is very well behaved...the rig plants and goes on hard acceleration...
well, as hard as a smallblock with well over 280,000 miles can run...it DID do great on Pismo in 2wd, second gear, high range at 5000rpm tho
well, as hard as a smallblock with well over 280,000 miles can run...it DID do great on Pismo in 2wd, second gear, high range at 5000rpm tho
I'd say "well designed" is key when using shorter links! Shorter links would have a smaller window of good travel. I say this meaning "where the axle travels up and down, not forwards and back". You want your suspension to travel up and down for sure, and if your links are too steep it won't. Also shorter links make for less travel, and less room for error when setting it all up. You want your ride height ,center tracking as well as your actual travel all just right, so there aren't problems. This would take much planning and wouldn't be as easy, but there are benifits
Shorter links would be stronger and flex much less than longer ones! It may also offer more positions for mounting points.
I found this photo last night and it's a good representation of how you could raise the lower brackets and keep the proper separation at the frame. I'm guessing that shorter links were used in order to keep the right triangulation with narrower mounting points in between the frame. It looks like the best way to mount the lower links as high as possible.
alot of speculation in here. Only a few with real experience.:whoops:
Heres my toyota. It works well.
Less seperation at the frame end than the axle end is key.
Like doc said never spread the seperation further at the frame than the axle.
Start looking and asking "comp" guys about the calculator. Its a starting point, not gospel.
Most guys end up drilling a few upper link mount holes at the frame and end up using one higher than originaly planned by the calculator.
Links should be as close to level as you can, but if one is going to be angled more than the other than is should be the lower. Uppers level, lowers barely angled down to axle, barely.
I never want my upper links to run uphill to the pumpkin.
I believe you want the uppers 80 percent on the lenght of the lowers and the same for seperation (frame sep 80 percent of axle sep).
Heres my toyota. It works well.
Less seperation at the frame end than the axle end is key.
Like doc said never spread the seperation further at the frame than the axle.
Start looking and asking "comp" guys about the calculator. Its a starting point, not gospel.
Most guys end up drilling a few upper link mount holes at the frame and end up using one higher than originaly planned by the calculator.
Links should be as close to level as you can, but if one is going to be angled more than the other than is should be the lower. Uppers level, lowers barely angled down to axle, barely.
I never want my upper links to run uphill to the pumpkin.
I believe you want the uppers 80 percent on the lenght of the lowers and the same for seperation (frame sep 80 percent of axle sep).
I couldn't resist throwing my 2 cents into the mix on this. I am a novice when it comes to suspension design but if my experience with building a triangulated 4 link rear and 3 link/panhard front has taught me anything it's that you can only build what fits into your rig. No offense Chop Shop (nice rig by the way) but you have a bit of an advantage over a lot of us that have kept the rear half of our trucks. I do agree with Doc/Shop that frame end separation should be less than axle end because of the negative effect on the pinion angle. I'll probably be burned at the stake for saying this but....When I first started playing around with the idea of building my 3/4 link I messed with the calculator but...When it came time to build it I did not use it again. I followed a few simple rules, keep the links as flat as possible, build some adjustability into the links, keep the panhard as flat as possible and also as parrallel with the drag link as possible at ride height, BUILD WHAT FITS, and of course don't burn anything in untill you have that warm and fuzzy feeling. I feel pretty good about my build but I guess time will tell if avoiding the calculator was a good idea or not.
Chop shop I don't see any bump stops in there at all, or limit straps? It looks like your links might be hitting there on the driver side frame end stopping the up travel of your suspension. Is this what your using to stop the up travel before your tire crashes into the coilovers? If so, that is no good at all!!!! You need a bumpstop of some kind for sure, and limit straps. Also your waisting all of whats left of your shock looks like 4" of travel or so! Why, your tire is obviously in the way to get any more up travel?
I personally don't think it is a good idea for your tire to get so close to your coilover, I think it's a real bad idea.
Having your links so close together at the frame will give you low squat numbers and less up travel, if you designed it for that fine.
I have a ton more experience than you'd probably think! I'm the first to admit I don't know everything.
Your rear axle is bad ass though!
I personally don't think it is a good idea for your tire to get so close to your coilover, I think it's a real bad idea.
Having your links so close together at the frame will give you low squat numbers and less up travel, if you designed it for that fine.
I have a ton more experience than you'd probably think! I'm the first to admit I don't know everything.
Your rear axle is bad ass though!
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My links dont hit at all. Its the angle of the pics.
The pics I posted were on my way to Bobbys to charge the shocks and I had yet to install any straps. It has limit straps and a limmiter on the diff aswell.
The tires DO NOT rub the shocks at all. This is a guess based on the pic of the truck when it was flexed on the lift with different wheels. It is fine now.
I do not have any bumpstops cuz its a wore out 22r, it will never jump anything. The coils are setup so the top coil is a 14 inch 100# and the lower is a 350# the top coils adjuster is setup to bottom out right before the top coil binds and then put the load on the lower coil ramping it up on the 350 rate quickly acting as a bumpstop of sorts.
The truck is setup to have about 6 inches of up travel. way more than enough. If you think an 18 inch shock should have 9 inches of up and 9 inches of down travel, then you have alot to learn.
with 6 inches up and 9 inches of droop that leaves 3 inches of shaft in the shock body at all times lowering the chance of a bent shaft.
I have many hours in this truck and most is hand built and you compliment me on the mailorder axle housing? Thanks I guess?
First shot is full stuff tire/shock clearance and second pic is full droop shock/frame clearance.
Third shot is when it was sitting on "full stuff" while building it. It clearly shows links clearing at full compression with an inch of shaft left, just enough for the shaft mounted bumpstops.
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- #35
So after some tweaking, this is what I've come to. Woody’s suggestion of an AS around 80 go me to thinking, so I moved the numbers around and heres where I'm at. I also had to shorten my upper frame side location as it interfered with my TC. so with that I had to go through and move my links around a little. I shortened my lowers by a few inches. As it sits now, the only adjustment that I have built into my links will move the AS up, and I don't see to many other options other than putting brackets in places I don't want them such as under the frame. I realize that my lower links already hang in that direction but there’s not a lot can do about that. I'll post some pics of the brackets and axel. I also had to notch the body mounts for the lower frame side links but it will be glued to the bracket so no harm done.
I realize that this isn't an ideal set up for a dedicated trailer queen but, but this isn't a trailer queen so.......
I think I'm going to notch the frame for the coilovers to go up through the fender wells. I'm pretty sure since this is what I'm planning/want to do, that it won't work.
I realize that this isn't an ideal set up for a dedicated trailer queen but, but this isn't a trailer queen so.......
I think I'm going to notch the frame for the coilovers to go up through the fender wells. I'm pretty sure since this is what I'm planning/want to do, that it won't work.
- Thread starter
- #36
These are the axle mounts tacked in.
- Thread starter
- #37
The first two are of the frame side uppers. You can see where I had to notch the body mount. The last one is the centerline of my axle, it gives me a ~24 inch driveshaft. It just happened to line up with that hole in the frame. Does anybody have any pics of their rigs at about this location with 35's so I can get an idea of what it will look like. So far I think my rig will look very similar to Nota Fn jeep's.
Oh yah, and instead of 7075 al. I'm thinking of using 1/16th wall conduit with cardboard spacers........
Oh yah, and instead of 7075 al. I'm thinking of using 1/16th wall conduit with cardboard spacers........
Eskimo
SILVER Star
You really shouldn't be offering "advice" like this...
Smaller diameter for ground clearance? How can you even say that without laughing with those rock-anchor lower link mounts you have?? He's giving up 3/8" clearance. whoop-tee-fawkin-doo.
Rationalizing a weaker material is like having a "hub fuse". And by the way, while your links would have bent to the point of taking out your coilover shafts and snapping u-joints, his/my aluminum links would be back straight as an arrow.
OP: - great choice of material, especially in that size.. I'm "only" using 2" on my rockwell'd buggy, and they're holding up great.
If you're going to street drive a lot, I'd focus on reducing your roll oversteer as close to zero as you can, to help keep things pointed the right way when you get the body leaning.. I personally prefer even less AS than 80%, but also make sure it stays consistent throughout a reasonable range of travel.. I know I'm giving up a little bit of traction, but I can mat the throttle and peel out without any hopping... but that's an east coast technique..
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ETRNLBLZZ
Cool, I happy for you! It is nice to see someone use the good info thrown their way! Looks like you made some good compromises to get what you felt was important. I haven't checked in for a while, but it looks like a good set up to me, I'll bet your happy with it.
ESKIMO
I am sick of your down talk to me, even though you edited your last post some! Unlike you, I actually have a legit education of materials and their properties, real world experience and the stuff taught on paper. If you need to quote me as you have here and other threads do it accurately!!!! I told him to engineer it well because of its material properties, not to use the aluminum all together.
It is people like you wanting to be the "alpha dog" who scare people from asking the questions and getting good info out to the community. Also it scares others away from putting their stuff out there for us to see as they fear ridicule and disrespect from individuals like you. Who is really causing harm here?
It seems you have a real personal problem with me FINE! Expressing it on line is masturbation, but you have an open invitation. If you want to come out here and meet up with me to discuss it in person, eye to eye, I'm all for it! I mean that.
As for my rig, I did it to learn, and built it my way as I felt was best. Not exactly the way someone else told me to!! I made compromises, It's not perfect, neither is your rig I promise. I built what I felt would be the best point to start from. I plan to dial it all in AFTER I see how and what suits my driving style, and the terrain I use it on. Tell me, how else can I (or anyone else for that fact) know what I (they) want with out the experience of driving a cruiser w/ a 4-link, as I haven't until now?
If you want rid of me fine, I probably wont be around as much for a while. I have lots of priorities other than my cruiser right now. I just wanted to give back to the community that has been a benefit to me. If you actually read what I post, I try to say "I don't know everything", and own up to my wrongs. I have done my best to give good info, and share my ideas/opinions. Also I try my best to be RESPECTFUL to any one seeking help or needing it.
Cool, I happy for you! It is nice to see someone use the good info thrown their way! Looks like you made some good compromises to get what you felt was important. I haven't checked in for a while, but it looks like a good set up to me, I'll bet your happy with it.
ESKIMO
I am sick of your down talk to me, even though you edited your last post some! Unlike you, I actually have a legit education of materials and their properties, real world experience and the stuff taught on paper. If you need to quote me as you have here and other threads do it accurately!!!! I told him to engineer it well because of its material properties, not to use the aluminum all together.
It is people like you wanting to be the "alpha dog" who scare people from asking the questions and getting good info out to the community. Also it scares others away from putting their stuff out there for us to see as they fear ridicule and disrespect from individuals like you. Who is really causing harm here?
It seems you have a real personal problem with me FINE! Expressing it on line is masturbation, but you have an open invitation. If you want to come out here and meet up with me to discuss it in person, eye to eye, I'm all for it! I mean that.
As for my rig, I did it to learn, and built it my way as I felt was best. Not exactly the way someone else told me to!! I made compromises, It's not perfect, neither is your rig I promise. I built what I felt would be the best point to start from. I plan to dial it all in AFTER I see how and what suits my driving style, and the terrain I use it on. Tell me, how else can I (or anyone else for that fact) know what I (they) want with out the experience of driving a cruiser w/ a 4-link, as I haven't until now?
If you want rid of me fine, I probably wont be around as much for a while. I have lots of priorities other than my cruiser right now. I just wanted to give back to the community that has been a benefit to me. If you actually read what I post, I try to say "I don't know everything", and own up to my wrongs. I have done my best to give good info, and share my ideas/opinions. Also I try my best to be RESPECTFUL to any one seeking help or needing it.
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- Thread starter
- #40
Eskimo, Thanks, I need the encouragement to keep after the aluminum links, there’s pretty heavy opposition to even the idea. My buddy that was originally going to do the machining for me won't as he feels the material is not correct. So I'm glad to hear your using a thinner diameter than I'm proposing and you have nothing but good things to report with heavier axels. I think if for nothing other than keeping the controversy going, I will have to use al. Thanks also for the advice on the roll center, this is the stuff that I'm looking for. I'll work on the roll center, I'm planning on a sway bar anyway so we'll see if I can lower it as well.
notaf-ingjeep, Thanks as well, I totally agree, If somebody disagrees with you great, state it, but refrain from taking digs. It seems like you take an extra helping of sh&t on here. I say f it. you contribute your opinion, your ideas and your knowledge. good bad or in-between, ideas in this arena are just that ideas, there are a few out there that people can take away and there are a few that people may have thought about but now don't have to execute because somebody already made that mistake. so keep checking in and giving your 2 cents.
The banter between everybody is friggin hilarious!!
notaf-ingjeep, Thanks as well, I totally agree, If somebody disagrees with you great, state it, but refrain from taking digs. It seems like you take an extra helping of sh&t on here. I say f it. you contribute your opinion, your ideas and your knowledge. good bad or in-between, ideas in this arena are just that ideas, there are a few out there that people can take away and there are a few that people may have thought about but now don't have to execute because somebody already made that mistake. so keep checking in and giving your 2 cents.
The banter between everybody is friggin hilarious!!
