Triangulated Vs. Parallel Vs. Pro- Street 4 Links

[johnsrob]

Happy New Year to you boys,

I am always on the forum (everyday in fact) been a while since I said something.

Time has come to set up my rear suspension and I want to go with a 4 link. Many version of this suspension: Triangulated, Parallel and Pro-Street 4 links are out there. I am leaning toward the triangulated 4 link. Looking for some tribal knowledge in this area, this will be my first 4 link setup ever. What is a good brand, size and installation tips and what size rims and tires to use? I really want my set up to be operational my truck will indeed see some track time lol lol.

My truck is 1973 Stepside with a small block full roller with competition package AFR heads. She has some growl to her lol. I bought a 30 spline Eaton Detroit Truetrac (913A315 part number series 4) limited slip locker and Richmond Gear Ring and Pinion, 4.56 and the Richmond Gear Mega Ring and Pinion Installation Kits (831018M) for my 12 bolt. I really want to narrow this rear end and get some strange axles for the 4 links set-up. I have not installed this yet in my 12 bolt. Not really sure how much is going to cost to narrow the rear end and who can do it lol lol, I told this was my first.

Currently I have some brand new WELD Draglites 15x10 with 7 inches of backspacing 5on5 the single set bolt pattern and some Hoosier Pro-Street tires 29x 12.5 on the back now. I also have a belltech flip kit on the truck with 8 leafs in the leaf springs. That is how I am able to get away the size of tire tucked under the stepside fender and no rubbing of the tires.

Please feel free to critique my set up and make suggestion and I will appreciate any input. I really want a nice set-up that is operational. I really need some expertise in the area. I still currently in Fremont California but I like to let it be known I am originally from the best state in the world at this TEXAS. If any of you boys are local are in my area please feel free to look me up and maybe we can discuss over breakfast or cup of coffee.

[Super73]

Jonsrob

I am in Freakmont 3-4 days a week. PM me some time, we'll grab a cup of coffee of something.

[Marv D]

I guess first question is please explain the triangulated 4link. Are you speaking of something akin to the the old 60's GM stamped 4link like the Chevelles?

Just curious what is driving the decision towards the triangulated 4link? How much of a driver is this going to be?
I'm going to suggest going to the track and look under 1000 cars, those with / required to have stock suspension generaly have the original 4link reconstructed in some way, and have a ladderbar setup next to to. The other 999 have a standard solid rod end adjustable 4link or simply ladder bar/coilovers.

Only thing I really can offer here is a quote from Dave Morgan's book "Doorslammers"

Misery loves a bunch of adjustment holes in a suspension bracket

[johnsrob]

Hey Mr. Marv D and Super 73

You guys or the man on this forum, I mean big brothers to guys like myself. Thank you for taking the time reply to my post. I have copy a page I have been study and getting my info on the different 4 links. THE FIRST IMAGE IS A TRIANGULAR 4 LINK AND THE SECOND IMAGE THE PARALLEL

What's the difference between a triangulated 4 link and a parallel 4
link?
Which is better?

Both styles of 4 link accomplish the same thing... very simply, they hold the rear axle in
the vehicle. The function of a 4 link is to keep the rear axle in its proper place under the
vehicle. The bottom 2 links keep the axle in place front to back. The upper 2 links keep
the axle from rotating, keeping the pinion angle as constant as possible.





On a triangulated 4 link the uppers bars are placed at an angle to the
lowers. When connected securely to the axle and the frame they form
a "triangle". This is what keeps the rear axle centered under the
vehicle.




On a parallel style, a "panhard bar" must be used. It runs horizontally
across the vehicle connecting the axle to the frame, allowing only up
and down movement. Although there are several theories as to which
is "better", in the real world it comes down to available space and
preference.

A parallel 4 link fits most trucks better because the fuel tank is usually
right in front of the axle, inboard of the frame. A parallel is sometimes
easier to install because the link bar frame mount is one piece instead
of two... less time in placing and welding the upper bar mounts. But a
parallel 4 link requires a panhard bar which adds slightly to the
expense and can use up valuable space needed for the exhaust
system. A panhard bar will also induce a small amount of side to side
movement during suspension travel... not enough to feel but it may
concern the customer who has an extremely tight tire to fender
clearance. With a parallel 4 link you are locked into a sideframe link
position... with a triangulated 4 link the lower links can be placed
beside the frame or under the frame for clearance purposes.

Either system is very straightforward to install. You will spend more
time with the tape measure than the saw or welder. All else being
equal, for the absolute rookie, the parallel may be a bit easier to
visualize and understand during installation.


Triangulated 4 link (vs. parallel 4 link)

PROS
No side to side movement at all... you can run tighter tire to fender
clearance
Less hardware to buy and install (no panhard bar)
Allows flexibility in bar placement to avoid obstacles

CONS
Angled upper bars can interfere with exhaust
Angled upper bars can interfere with fuel tank on late model trucks
4 more attachment points to plot and install (parallel has bar mounts
built together)



Parallel 4 link (vs. triangulated 4 link)

PROS
Slightly easier to visualize and install (bar mounts are built together)
Can be installed beside framerail, inboard or outboard
May allow more room for exhaust (no angled upper bars)

CONS
Requires a panhard bar (extra cost and installation)
Panhard bar will induce a slight amount of side to side movement
during suspension travel... requires slightly more tire to fender
clearance
Panhard bar may interfere with exhaust



Why should I put a 4 link under my car?
What will a 4 link do better than a leafspring?

In a leafspring suspension, the leafs perform 2 functions. First, they
hold the rear axle in the car. They prevent both forward and aft
movement and minimize pinion angle change during suspension travel.
Secondly, while they are doing this, they also support the load of the
vehicle. For an OEM vehicle that has had thousands of hours of
development time behind it, and that will operate within a predictable
range of suspension travel, leafsprings do a very adequate job. The
problem occurs when the operating envelope is changed... lower ride
height, more horsepower, different weight distribution, maybe a
trailer... it's called hotrodding! The leafsprings cannot be expected to
perform as intended if the operating parameters are changed.

With a 4 link suspension, we have separated the function of locating
the rear axle and supporting the vehicle, just as GM has done since
1958. We like the 4 link rear suspension because of its ability to
properly locate the rear axle no matter how soft we want to make the
spring. With a leafspring rear suspension, softening the spring rate
can cause other problems such as side to side flex or axle wrap (when
the axle tries to twist the leafs out of the vehicle).




In setting up my rear 4 link air suspension, should I
place the airsprings in front or behind the axle? Inboard
or outboard of the framerail?

It really comes down to where there is the most room. A forward
position will offer slightly more travel and can sometimes offer better
ride quality. A rear position can offer slightly more load capacity. Any
spring, coil, leaf or air will perform better if placed farther apart under
the shassis. Keep in mind these performance differences are quite
small and that the real criteria should be available space in your
particular vehicle.



At what angle should I place the 4 link bars? The
panhard bar? How critical are the angles?

We typically try to place the lower bars level at ride height. This will
minimize "roll steer" (slight wheelbase change caused by the arc of the
bars going through their travel). The upper bars should also be level,
or slightly down at the front if need be. This configuration will provide
stable handling and braking characteristics. It is important to get the
bars exactly the same from side to side to avoid unpredictable
handling problems. It is also extremely important to make sure the
panhard bar is level at your highway ride height. This will minimize side
travel of the rear axle induced by the arc of the panhard bar going
through its travel. Obviously there are precise formulas for placement
of the 4 link bars to maximize certain performance criteria, but these
performance differences are quite small on a road car. Put the bars in
level, or close to it, at ride height, and you'll be fine.


What about "reverse" 4 links? What happens when you
run the bars backwards?

NO NO NO!!! By the way, did we say NO?! It doesn't matter what the
truck magazines say... DO NOT run the 4 link bars backwards! Here's
what happens... When the top bars are run backwards, the diverging
arcs of the upper and lower bars will create such a massive pinion
angle change that under extreme amounts of suspension travel, you
may actually pull the driveshaft out of the transmission! If you want to
see this effect for yourself, get a sheet of pegboard and a couple of
yardsticks... simulate the scenario for yourself. The second effect of
running the upper bars backwards is completely screwed up handling
dynamics. With a normal 4 link, when you hit the brakes, the
suspension geometry wants to lift the rear of the vehicle... therefore
trying to "plant" the rear tires and assisting the braking action. When
the upper bars are reversed, this dynamic is eliminated or even
reversed... when you hit the brakes the suspension actually unloads
the tires thereby massively reducing available braking performance.
This is not our opinion... it is simply physics.

Then again I really could be splitting atoms here.

[Marv D]

Yeah that was what I thought. Again no expert here, but if your building a cruiser and want to spin the tires at the liocal cruises,, I don't think it matters which youchoose, the triangulated 4ling might be a nice cimple way of doing things.

If you making enough power to be conserned with hookin gup... 4link or ladderbar is the ONLY two I'd consider. Think abou tthe stresses on the angular deals with a vehicle that has enough power to wheelstand...... I see failure looking to happen.

[vin63]

Originally Posted by johnsrob

Happy New Year to you boys,

I am always on the forum (everyday in fact) been a while since I said something.

Time has come to set up my rear suspension and I want to go with a 4 link. Many version of this suspension: Triangulated, Parallel and Pro-Street 4 links are out there. I am leaning toward the triangulated 4 link. Looking for some tribal knowledge in this area, this will be my first 4 link setup ever. What is a good brand, size and installation tips and what size rims and tires to use? I really want my set up to be operational my truck will indeed see some track time lol lol.

My truck is 1973 Stepside with a small block full roller with competition package AFR heads. She has some growl to her lol. I bought a 30 spline Eaton Detroit Truetrac (913A315 part number series 4) limited slip locker and Richmond Gear Ring and Pinion, 4.56 and the Richmond Gear Mega Ring and Pinion Installation Kits (831018M) for my 12 bolt. I really want to narrow this rear end and get some strange axles for the 4 links set-up. I have not installed this yet in my 12 bolt. Not really sure how much is going to cost to narrow the rear end and who can do it lol lol, I told this was my first.

Currently I have some brand new WELD Draglites 15x10 with 7 inches of backspacing 5on5 the single set bolt pattern and some Hoosier Pro-Street tires 29x 12.5 on the back now. I also have a belltech flip kit on the truck with 8 leafs in the leaf springs. That is how I am able to get away the size of tire tucked under the stepside fender and no rubbing of the tires.

Please feel free to critique my set up and make suggestion and I will appreciate any input. I really want a nice set-up that is operational. I really need some expertise in the area. I still currently in Fremont California but I like to let it be known I am originally from the best state in the world at this TEXAS. If any of you boys are local are in my area please feel free to look me up and maybe we can discuss over breakfast or cup of coffee.

My initial questions are:
What is your primary goal for the truck (how much street v. strip driving do you honestly plan for the truck)?

If your plan is mostly strip, are you willing to actively monitor your instant center and pre-load, and make adjustments according to track conditions, etc?

I usually explain to friends and customers that a triangulated four-link eliminates the need for a housing centering device (panhard bar, watts link, track locators, wishbones, etc.). Most street parallel four-links do not permit as much adjustability as a drag race type four-link. As far as brands, I've installed many kits from Chris Alston's Chassisworks, and a couple from Art Morrison. Both companies offer different types of four-link systems, so check them out to see what fits your budget and plans for your truck.

http://www.cachassisworks.com/cac_products.html

http://artmorrison.com/homepage.html

[BigDan3131]

My El Camino with a reinforced stock type triangulated has run high 9's. I will be modding it this summer for more adjustabilty. My friends truck has the Poly Bushed Drag 4 Link and he drives it everywhere.

His truck:http://www.kellyandsoncrazypainters....y/IMG_0061.jpg, http://www.kellyandsoncrazypainters....y/IMG_0054.jpg

[phipp13]

straight, triangulated 4 link is not that important to me. when i think of hooking up i think of weight transfer which IMHO is more important. 4 links are by nature are short, Ladder bars are slightly longer. the trailing arm pivots on a coil spring rear c-10 are about 48" forward of the rear axle. the further forward your pivot point is the quicker your weight transfers to your rear tires. Also maintaining a minimum -2degree rear pinion angle and the compression and rebound of your shock settings are critical to staying hooked up. look at Kevin T's passtime run he ran(correct me if i'm wrong kev) boxed trailing arms and coilovers w/ a 10" or 12 inch slick and shot 350HP nitrous to his BBC dead out the hole and his 68 stood up was GONE! I made my own 50" 1"x.125 chrome molly ladder bars& panhard bar w/ QA1 adjustable coilovers. moved the pivot point aprox 2" forward of the stock location under the cab and i have no doubt it will hook solid, also i have back halfed the frame w 2"x4"x.125 boxed tubing and tied it together diagonally underneath the truck with some more 1' x .125" chrome molly tubing adding rigidity to the frame. I used 1" tubing because the truck has been lowered 4.5" up front, 6.5" rear and i'm running 3" exhaust between the frame rails on the street. i worked in a chassis shop for 10+ years i have no doubts in the design. My truck is going to paint 3-1-12 and will be completed by 4 july 2012. personally i would only use 4 link setup on c-10 if i was bagging it. just my 2 cents.

[kpeztruck]

[QUOTE=phipp13;5104623]straight, triangulated 4 link is not that important to me. when i think of hooking up i think of weight transfer which IMHO is more important. 4 links are by nature are short, Ladder bars are slightly longer.

This statement is not true. The four link bars are short, I agree. But they are short for packaging into a car. You must continue to draw lines through your uppers and forward, and through your lowers and forward to find your intersect point. That intersect point will be your instant center. Some pro stock and promaod cars are running instant centers as far out as 60+". Can you imagin how that ladder bar would feel going through your back, and abdomen to package a 60+" ladder bar in most cars. We do have the luxury in these trucks of having much more room. But you will never have the adjsutment options with a ladder bar, triangulated 4-link, as you will with a traditional parallel four-link.

That being said, I still run factory trailing arms, but with Coil-overs, and an anti-roll bar. At this point in time, I do not need the misery that comes with more adjustment holes. I have been 1.24 60' on a 29x10.5 tire. I just did not want a misunderstanding of how things work, to turn into other being misled. I hope all this helps. If I were not contained by rules that state stock-suspension, my choice would be parallel 4-link for the long term future. Paul

[Super73]

Paul is correct. The 4-link bars nead to be looked at from a side view. Continue the line they are on from rod end to rod end. When the upper meets the lower, that the actual IC distance from the tire.

Most the time you will find a ladder bar has a shorter IC distance than a 4-link.


Paul, A buddy of mine races old gassers. His 57 actually uses a ladder bar where the front hole is about equal to the door hinge. Talk about a looooonnnnggggg ladder bar. But the car is up in the air with a solid axle front end.

[phipp13]

my bad for the miss leading statement.

[kpeztruck]

Originally Posted by phipp13

my bad for the miss leading statement.

Don't even give it a second thought man. I think I made this chassis, and suspension thing so complicated in my mind, that it took me longer to grasp it all. There is a ton of information on here, but Dave Morgan's book about door car chassis is very helpfull, and can be found at a Summit store on sale at times.
Paul

[johnsrob]

Mann, This is literally a like to take in. My buddy has a 72 stepside and he has trailing arms, but I don't I have trailing arms.I have a leaf spring set-up. I have been really looking into the various 4 links and ladder bar set-ups. See you guys have suspension down to a science. My question is a 4 link is a better way for me to go oppose the ladder set-up for leaf springs. The truck will see some track time and driven on the street. My ultimate goal is to hook up, pull the front ones off the ground and GO!!!!! I spend the tires with literally no effort. I don't care about "SHOW and want "GO" lol.

[johnsrob]

I apologize for taking so long to getting back to guys, I work GRAVEYARD shift. That's what funding the whole operation. I look at the Chris Alston's website like you told me, they have a sub department called KP Componets they have a bolt on 4 link kit for my year of truck.

To answer Mr. VIN63 questions if am taught how to do it yes of course I will monitor, adjust, and even feed it if it's required. LOL LOL

I just want some direction and yes some take by hand and teach. I just don't want to waste any money, I have been through that. Broke, Busted and Disgusted is not a good look on me let alone anyone.

[kpeztruck]

A street rod style 4- link with bushings will move around if hit with a lot of power. A friend of mine did this, and said it felt like it had uncontrollable rear steer. He ended up changing over to a race style four link with a panhard bar to fix the problem. Please understand that hiem joints require cleaning and maintenance, even more so when street driven. Ladder bars are very simple in operation, but do not allow you to change instant center length. If it were me in your position, I would install a race four link set up. This speed thing is addictive, and will lead to more power in the future. You might as well plan for unforseen long term needs. Paul Baxter

[vin63]

Originally Posted by johnsrob

...My ultimate goal is to hook up, pull the front ones off the ground and GO!!!!! I spend the tires with literally no effort. I don't care about "SHOW and want "GO" lol.

Originally Posted by johnsrob

...To answer Mr. VIN63 questions if am taught how to do it yes of course I will monitor, adjust, and even feed it if it's required. LOL LOL

I just want some direction and yes some take by hand and teach. I just don't want to waste any money, I have been through that. Broke, Busted and Disgusted is not a good look on me let alone anyone.

If your primary goal is to "hook up," I would recommend going with a drag race four-link, get rid of the leaf springs and go with a coil-over shock configuration. The reason I say that is because if you keep the leaf springs, you'll have to install a rear housing isolator or floater device, and I've never really been able to make those work very well. Plus, with a drag race four-link, it will be a lot safer in what you want to do (the street style, poly bushed kits permit a lot of movement and can cause unpredictable steering, especially if you pull the front end off the ground, plus they absorb energy). The drag race four-link will permit you to locate instant center relatively far forward to compensate for the large weight bias at the front of our trucks. Just as an example, the instant center on my Super Gas 1963 Chevy II hovers around 53 inches forward and 5 inches above the ground and my weight distribution is 52% front to 48% rear. If you want to learn more about the geometries and applications behind a four-link suspension and setting up a chassis, Rick Jones' chassis book is a good start http://www.rjracecars.com/The-Rick-J...-Prodview.html...it's not too expensive. If want more in depth info, you can get Jerry Bickel's book http://www.jerrybickel.com/complete-...t-rt-2013.html...it's a bit more money. Let us know what you decide to do.

[johnsrob]

Thank you Mr. VIN63

Well what do you suggest from the Chris Alston website, do you think I just go ahead and back half the whole thing and and install a drag race 4 link rear frame clips. like one these on the website. its looking that way huh

http://www.cachassisworks.com/c-398-...ame-clips.aspx

[johnsrob]

Ok everybody,

I think I got it, after researching taking all the input given calaculating and looking at what I really want for the vehicle. I call Chris Alston Chassis good thing they are right here by me in Sacremento about a 1 hour 30 min drive.


DRAG-RACE ELIMINATOR II 4-LINK REAR CLIP - 3x2"
FRAME RAILS

Description: CLIP 4-LINK DRAG ELIMINATOR II 3x2"

SYSTEM CONTAINS 3x2" BOX-TUBE FRAME CLIP;

ELIMINATOR II DRAG RACE 4-LINK WITH 4130 ROD

ENDS; LOCATER; ANTI-ROLL BAR; BILLET SHOCK

MOUNTS. OPTIONS: LOCATER, SHOCKS, SPRINGS, WHEEL


TUBS, AND ROLL CAGE.

SKU: 78E223

Price: $1,377.00



Also Add VariShock Coil-Over - Bearing Eye Top, Bearing

Eye Standard Base - Double Adj., 7.15" Travel

Description: C/O QUICKSET 2, 7.15 TRAVL COM8 ,

SPHERICAL ENDS 1/2 BORE x 1" WIDE, 20.10" EXTENDED

LENGTH, STANDARD VALVING

SKU: VAS 11211-715

just for $150 more

Grand total out the door $2175.00

I think if I go this route I save my self a lot a headaches and can achieve what I want.

Oh Yeah, The guy (MIKE) says the kit sit 5 to 6 inches low and can take a 33 X 18.5 tire easy. What do you guys think, just run my 12 bolt 456 gears, True Trac linited slip, and some new axles till it DIES!!!!