Read up on anti-squat and you will understand. To put it short, the axle will want to drive under the truck giving you wicked hop unless you build as i have described above. The greater the angle between axle and frame attachment the greater the anti-squat, this is bad. The only way tame this with this suspension design is to do as I have described, or use band-aids like tight limit straps. 4 links create a virtual pivot and allow you to end up with a numerically low anti-squat number thru the travel of the suspension, this is why they are superior.
Front and rear x-link in a 60-series cruiser ute. (1 Viewer)
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Read up on anti-squat and you will understand. To put it short, the axle will want to drive under the truck giving you wicked hop unless you build as i have described above. The greater the angle between axle and frame attachment the greater the anti-squat, this is bad. The only way tame this with this suspension design is to do as I have described, or use band-aids like tight limit straps. 4 links create a virtual pivot and allow you to end up with a numerically low anti-squat number thru the travel of the suspension, this is why they are superior.
here is a good article, not rockcrawling but all the concepts are the same.
Rear Suspension - Instant Center - Mini Truckin' Magazine
Ignore their comment about anti-squat not being a major concern, in an offroad application where you are trying to climb a nasty ledge it is the biggest concern. In an offroad application low anti-squat is good, shoot for ~50-70%
There is a metric ton of info on pirate
This is the drawing that u need to understand to comprehend what i'm getting at in my earlier post.
I'll try to dig up some pirate threads, I read so many good ones a few years back that dug deep into suspension theory investigating cause and effect trade offs and compromises but they are hard to find.
Rear Suspension - Instant Center - Mini Truckin' Magazine
Ignore their comment about anti-squat not being a major concern, in an offroad application where you are trying to climb a nasty ledge it is the biggest concern. In an offroad application low anti-squat is good, shoot for ~50-70%
There is a metric ton of info on pirate
This is the drawing that u need to understand to comprehend what i'm getting at in my earlier post.
I'll try to dig up some pirate threads, I read so many good ones a few years back that dug deep into suspension theory investigating cause and effect trade offs and compromises but they are hard to find.
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here is a pretty good thread, you have to figure out who knows what they are talking about and who doesn't
Link suspensions for dummies? - Pirate4x4.Com Bulletin Board
StrangeRover is a good one to listen to
Link suspensions for dummies? - Pirate4x4.Com Bulletin Board
StrangeRover is a good one to listen to
Tapage
Club 4X4 Panamá
Thanks for this lesson dude .. everyday learning ..
Link to 4link calculator
http://mysite.verizon.net/triaged/files/4BarLinkV3.0.zip
Here is a good explaination of anti-squat and diagrams
"When a vehicle accelerates, the weight shifts rearward. The higher the weight is above the ground, the greater the shift off the front and onto the rear. This extra weight will compress the rear suspension, make it SQUAT. But there is also a torque on the rear axle, equal and opposite of the tire torque. The pinion will try to rotate upward. The links resist this torque by putting forces into the frame. These forces may try to lift upward. The upward force will cancel some of the squat from the weight shift, ANTI-SQUAT. The easiest suspension to understand is a ladder bar/radius arm setup. if the axle trys to rotate backwards, the end of the arm will push upwards. The shorter the arm, the more upward force it will create. The greater the force, the more anti-squat it has. For understanding anti-squat, a 4 link can be visualized as a ladder bar, wherever the links would cross is the theoretical length of the arm. This picture is a ladder arm and 4 link with the same anti-squat geometry
For more antisquat, the 4 link should have more angle, making the intersection shorter, for less anti-squat the links should have less angle. The height of the intersection is also important, the higher it is the more antisquat it has. Another pic, the red setup has more than 100% anti-squat, the blue has less. The drawing has a horizontal line through the CG, and a vertical line through the front wheel. Then a line is drawn from the rear tire contact patch through the 4 link intersection, till it crosses the front axle. In the drawing the CG happens to be 38" the red suspension crosses the front axle at 48" 48/38 = 1.26. Thats 126% anti-squat."
It should also be noted that the COG measurment is of the unsprung weight
Another cool analysis to make things more complicated
Anti Squat, the final answer - Pirate4x4.Com Bulletin Board
http://mysite.verizon.net/triaged/files/4BarLinkV3.0.zip
Here is a good explaination of anti-squat and diagrams
"When a vehicle accelerates, the weight shifts rearward. The higher the weight is above the ground, the greater the shift off the front and onto the rear. This extra weight will compress the rear suspension, make it SQUAT. But there is also a torque on the rear axle, equal and opposite of the tire torque. The pinion will try to rotate upward. The links resist this torque by putting forces into the frame. These forces may try to lift upward. The upward force will cancel some of the squat from the weight shift, ANTI-SQUAT. The easiest suspension to understand is a ladder bar/radius arm setup. if the axle trys to rotate backwards, the end of the arm will push upwards. The shorter the arm, the more upward force it will create. The greater the force, the more anti-squat it has. For understanding anti-squat, a 4 link can be visualized as a ladder bar, wherever the links would cross is the theoretical length of the arm. This picture is a ladder arm and 4 link with the same anti-squat geometry
For more antisquat, the 4 link should have more angle, making the intersection shorter, for less anti-squat the links should have less angle. The height of the intersection is also important, the higher it is the more antisquat it has. Another pic, the red setup has more than 100% anti-squat, the blue has less. The drawing has a horizontal line through the CG, and a vertical line through the front wheel. Then a line is drawn from the rear tire contact patch through the 4 link intersection, till it crosses the front axle. In the drawing the CG happens to be 38" the red suspension crosses the front axle at 48" 48/38 = 1.26. Thats 126% anti-squat."
It should also be noted that the COG measurment is of the unsprung weight
Another cool analysis to make things more complicated
Anti Squat, the final answer - Pirate4x4.Com Bulletin Board
- Thread starter
- #27
O.k so I picked a few things up from pirate, however all of this information relates to 4-link setups, I am sure some of the principles can be related to a Radius arm setup.
These are:
-NO perfect setup for all rigs, even if they are all rockcrawlers. Wheelbase, width, height, horsepower, weight, driving style, terrain ect all factor into the design.
-You should start with a tried and true setup, with a resonalble antisquat, a fairly high and level roll center and go from there. Reguardless you will have to make some adjustments after you get out there and see how the rig responds.
- make the radius arms as long as you reasonably can
- make them as flat as you reasonably can
- make the roll axis as high as you reasonably can (what is a roll axis?)
Anyway I feel that I could make all of the above points incorporated into my design and constructon of my suspension.
Something completely separate I thought of also was the following to incorporate into the build:
-4 identical length Radius arms,
-4 identical width mounts on the front and rear diffs,
-4 identical width mounts on the chassis (for the front and rear arms)
-identical width coil-over/air shox upper mounts, and finally
having the same angle of travel for the front and rear coil-over/ air shox both front and back and towards the centre of the vehicle.
By having identical front adn rear suspension geometry I feel that the truck would be much more predicatible and get better travel in all situations.
These are:
-NO perfect setup for all rigs, even if they are all rockcrawlers. Wheelbase, width, height, horsepower, weight, driving style, terrain ect all factor into the design.
-You should start with a tried and true setup, with a resonalble antisquat, a fairly high and level roll center and go from there. Reguardless you will have to make some adjustments after you get out there and see how the rig responds.
- make the radius arms as long as you reasonably can
- make them as flat as you reasonably can
- make the roll axis as high as you reasonably can (what is a roll axis?
)Anyway I feel that I could make all of the above points incorporated into my design and constructon of my suspension.
Something completely separate I thought of also was the following to incorporate into the build:
-4 identical length Radius arms,
-4 identical width mounts on the front and rear diffs,
-4 identical width mounts on the chassis (for the front and rear arms)
-identical width coil-over/air shox upper mounts, and finally
having the same angle of travel for the front and rear coil-over/ air shox both front and back and towards the centre of the vehicle.
By having identical front adn rear suspension geometry I feel that the truck would be much more predicatible and get better travel in all situations.
True but it isn't really necessary understanding the physics, that is what is important. The number that most everyone uses as a guild line is the height of the top bolt on the bellhousing.
I think you mean roll center, which will be the center of your panhard
You have apparently made up your mind
, why did you ask for opinions- Thread starter
- #30
True but it isn't really necessary understanding the physics, that is what is important. The number that most everyone uses as a guild line is the height of the top bolt on the bellhousing.
I think you mean roll center, which will be the center of your panhard
You have apparently made up your mind
That is a bloody beaut rule of thumb.
Top bolt on the bellhousing.
But what about roll centre if you have no panhard?
Is there another option.
the easiest way to figure it out is with the 4-link calculator I posted above
but it isn't too hard to understand, it is the point which the axle pivots around so:
if I am thinking correctly
a 3 link wishbone roll center is the pivot point on the wishbone frame.
a 4 link where only one set of links are triangulated, it is the point where those links converge.
a 4 link where both links are triangulated, I don't have an answer, my understanding is that it still gives you a high roll center,
but it seams like it would have to be in between the two convergance points. I need to play with the calculator to understand this.
but it isn't too hard to understand, it is the point which the axle pivots around so:
if I am thinking correctly
a 3 link wishbone roll center is the pivot point on the wishbone frame.
a 4 link where only one set of links are triangulated, it is the point where those links converge.
a 4 link where both links are triangulated, I don't have an answer, my understanding is that it still gives you a high roll center,
but it seams like it would have to be in between the two convergance points. I need to play with the calculator to understand this.if you are doing an x-link, it is the essentially the same as a radius arm suspension without the binding, you will need a panhard, roll center is easy.
And just so you know what I am trying to achieve.....
I plan on using coil-overs, and I want more flex than these pictures however I don't want mega flex because I do alot of high speed mud runnng also
im SUA and have more flex than that...
looks like that truck is too tho.
- Thread starter
- #36
My truck is SUA and it has fully standard suspension (except the 2 leaves I took out of each rar spring pack
Because i am building a trailer queen I am considering my options.
haha my options are as follows...... (thank-you bustanutley, mace, and anyone else that offered idea/ reasoning.
)Go with a triangulated 4-link.
Make a 'true' 3-link.
And I must say that I most likely go with the 'true' 3-link, something of the TG design, except use .500" wall instead of the recomended .250" wall 2" pipe and also make the upper and lower links longer.
(and as per another thread I threw up) I will most likely go with Fox 2.5" Air-shox.
TG is not the end all be all btw. Just because they designed somethign for a mini does not mean that it is the best solution for a 60.
A true 3 link I like for the front. In the rear, a doubly triangulated 4 link is pimp.. But I did a wishbone three link on my 60 that seems to be a very balanced suspension system (not much flex tho, still better than the rig you posted but..)
I looked at your build on TG's site.
If you are planning on running 2 sets of calipers on the front. You will need a custom master cylinder.. The 1" bore aint gonna cut it. Think of how much fluid you will have to move!
A true 3 link I like for the front. In the rear, a doubly triangulated 4 link is pimp.. But I did a wishbone three link on my 60 that seems to be a very balanced suspension system (not much flex tho, still better than the rig you posted but..)
I looked at your build on TG's site.
If you are planning on running 2 sets of calipers on the front. You will need a custom master cylinder.. The 1" bore aint gonna cut it. Think of how much fluid you will have to move!
- Thread starter
- #38
hello again!
I realise that TG is not the be all and end all but what they offer allows me to buy a certain amount of suspension parts instead of fabricating all of them myself. Thus speding up my build.......... I am really sick of researching **** on the intermanet. But better off doing it first time round than rebuilding my creation in a couple of months.
Any way about the brakes.
I have e-mail wilwood and another ob of brake guys. I wanted to see what they could offer and basically this is what the brake guru's said:
On the road you NEED a short throw high-pressure MC. The MC must deliver maximum performance (which is derivitive of your effective disc ratio, and lever ratio) because you have a reliable sturdy braking platform (road-car), and you have a solid footing (asphalt). The harder the pedal and the shorter the throw the more feel you get, and the braking performance is increased to achieve a realistic goal.
Off-road (trail-rig) a 1" master cylinder will serve the purpose of a standard 80-series set-up (single pot rear, and quad pot fronts). By adding a further set of quad pot caliper I will effectively decrease system pressure for an idential pedal effort due to the pedal lever ratio not being altered. This means that you are correct Mace I will have a longer pedal throw. Anyway back to the facts: By increasing pedal effort (the amount I have to push on the pedal) I will have substantially more control and feel in an off-road scenario due to the more lever effort required.
If (as standard) I have 1" throw for 0% braking and 4" throw for 100% braking I may (no-one is quite sure, but brake techs said a 60% increase in throw length is more than reasonable). After adding the extra calipers I will have about 1" throw @ 0% and maybe 6 1/2" throw @ 100%.
I hope that all makes sense.
I realise that TG is not the be all and end all but what they offer allows me to buy a certain amount of suspension parts instead of fabricating all of them myself.
Thus speding up my build.......... I am really sick of researching **** on the intermanet. But better off doing it first time round than rebuilding my creation in a couple of months.Any way about the brakes.
I have e-mail wilwood and another ob of brake guys. I wanted to see what they could offer and basically this is what the brake guru's said:
On the road you NEED a short throw high-pressure MC. The MC must deliver maximum performance (which is derivitive of your effective disc ratio, and lever ratio) because you have a reliable sturdy braking platform (road-car), and you have a solid footing (asphalt). The harder the pedal and the shorter the throw the more feel you get, and the braking performance is increased to achieve a realistic goal.
Off-road (trail-rig) a 1" master cylinder will serve the purpose of a standard 80-series set-up (single pot rear, and quad pot fronts). By adding a further set of quad pot caliper I will effectively decrease system pressure for an idential pedal effort due to the pedal lever ratio not being altered. This means that you are correct Mace I will have a longer pedal throw. Anyway back to the facts: By increasing pedal effort (the amount I have to push on the pedal) I will have substantially more control and feel in an off-road scenario due to the more lever effort required.
If (as standard) I have 1" throw for 0% braking and 4" throw for 100% braking I may (no-one is quite sure, but brake techs said a 60% increase in throw length is more than reasonable). After adding the extra calipers I will have about 1" throw @ 0% and maybe 6 1/2" throw @ 100%.
I hope that all makes sense.
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Jonathan_Ferguson
★ is in the wrong locale
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haha my options are as follows...... (thank-you bustanutley, mace, and anyone else that offered idea/ reasoning.
Go with a triangulated 4-link.
Make a 'true' 3-link.
And I must say that I most likely go with the 'true' 3-link, something of the TG design, except use .500" wall instead of the recomended .250" wall 2" pipe and also make the upper and lower links longer.
(and as per another thread I threw up) I will most likely go with Fox 2.5" Air-shox.
hello again!
I realise that TG is not the be all and end all but what they offer allows me to buy a certain amount of suspension parts instead of fabricating all of them myself.
Any way about the brakes.
I have e-mail wilwood and another ob of brake guys. I wanted to see what they could offer and basically this is what the brake guru's said:
On the road you NEED a short throw high-pressure MC. The MC must deliver maximum performance (which is derivitive of your effective disc ratio, and lever ratio) because you have a reliable sturdy braking platform (road-car), and you have a solid footing (asphalt). The harder the pedal and the shorter the throw the more feel you get, and the braking performance is increased to achieve a realistic goal.
Off-road (trail-rig) a 1" master cylinder will serve the purpose of a standard 80-series set-up (single pot rear, and quad pot fronts). By adding a further set of quad pot caliper I will effectively decrease system pressure for an idential pedal effort due to the pedal lever ratio not being altered. This means that you are correct Mace I will have a longer pedal throw. Anyway back to the facts: By increasing pedal effort (the amount I have to push on the pedal) I will have substantially more control and feel in an off-road scenario due to the more lever effort required.
If (as standard) I have 1" throw for 0% braking and 4" throw for 100% braking I may (no-one is quite sure, but brake techs said a 60% increase in throw length is more than reasonable). After adding the extra calipers I will have about 1" throw @ 0% and maybe 6 1/2" throw @ 100%.
I hope that all makes sense.
By the time you buy that kit and modify it to be what you need, it will be cheaper to fabricate it yourself..
Go try to maintain the rig on a steep hill with a second set of calipers and come back and chat with us..
Think of it another way. Off road you can EASILY lock up the tires (low frictional coefficient) why would additional calipers help?
