Upper link bar angle
 

Hey first time posting on here ...im doing air ride on my square and im currently working on my tri 4 link..now i have the bottom bars tacked up and am ready to tack the uppers up but im a little unsure of exactly how they should be ...i have a piece of 6x2 tubing btwn the rails as a xmember for the upper links and I was planning on welding the upper bar brackets to it but after notching for the driveshaft i wouldnt be able to triangulate them much, they look almost straight....question i have is what angle should the top bars be on...someone told me level but i know ive seen them on angle.....ps how do i post a pic to go with this post

Re: Upper link bar angle
 

Level will work for street driving. If yourmputting serious power to the ground you'd want the bottom bar level and the top bar angled down. In the front ..so if they continued on an imaginary line the lines would intersect about 3 ft ahead of the front bumper..search for ron sutton suspension..hes a master of suspension setup..he has a tutorial on proper setups

Thanks for the input. It's funny bc I see a lot of pics with the bars angled up sloping towards the back..how can I share a pic ?
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Re: Upper link bar angle
 

The lower bar should be horizontal at ride height.

Upper bar horizontal will be fine (as mentioned above).

I have seen some tutorials suggest angling the upper bars so that their centerline intersects with the lower arm centerline at about the front bumper of the vehicle.

Angling steeper increases anti-squat (usually good for launch, not always good for cornering).

DO NOT have the upper bars angle ~up~, such that the centerlines intersect ~behind~ the truck. Don't do that.

Re: Upper link bar angle
 

5150..different devices vari on how to do pics...on mine if I scroll down from where I reply to a post there's a (manage attachments) box..I click that and it gives me the option to add 5 pics..clicking on those takes me to my photo gallery where I chose my pic..then hit download and its done..what device are you using?

Re: Upper link bar angle
 

After rereading you question I think we may not have understood what you asked...I think the angle your referring to is the top bar of the triangulated 4 link..the angles of the the top bars if you looked straight down at it from above..I'm thinking you mean you can't bring the front of the top bars together because if your driveshaft loop...is this right? You may have to do a reverse triangulation..or go with a panhard bar or watts link...but from a side view the bars should be level..

Re: Upper link bar angle
 

Mongo iPhone
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Re: Upper link bar angle
 

I don't know about a I-anything...I know people have difficulty with those

Re: Upper link bar angle
 

I found my instant center witch came out to 5 degrees. Should I tack them at 5 degrees or level?

Re: Upper link bar angle
 

Your instant center is a location. What location did you pick? If it's around the front bumper, and the upper arms end up at 5° down (at ride height), then tack it in. 5° seems a bit steep off the top of my head, but I certainly haven't done the measurements for the C10.

.... or did you use one of them 4-link calculators available online? If they say 5° and you're happy with the amount of anit-squat, giv'er. It may be worthwhile to make them adjustable - not a whole lot more work.

This is on my Pontiac Firefly (Chevy Sprint) (notice the forward mounts):

http://gwellwood.com/wordpress/wp-co...73-480x360.jpg

Re: Upper link bar angle
 

Not to hi jack. ..too much... but that 10 bolt must be a quarter of the weight of the car almost, ha. What on earth are you buildin? Got a thread?

Re: Upper link bar angle
 

What I did was put a string from the upper bar mount on the rear end and ran it to the fromt of my bumper where it intersected won the lower bar and I put a angle finder on the string and the angle was 5*... am I confused lol

Re: Upper link bar angle
 

That intersection point will be different depending on your wheelbase..thus changing that top bar angle..i agree with skinny,, if your happy with it then go with it..should be ok..but you can raise the front mount up to the point of being level and still be ok for just a street cruiser..adj front brackets like he used are great for fine tuning..the intersection point of the top and bottom bars is more critical in a higher hp truck..adj the angle of the bars moves the intersection point foward or back and thus affects the weight transfer of the truck under hard acceleration.

Re: Upper link bar angle
 

Consensus seems to be put em level. And it's a cruzer so level it is. Thanks for the help. I shoulda tried this forum months ago when I was told about it..

Re: Upper link bar angle
 

Another ? Is it ok to clock the axle bar bracket forward or should it be at 12o'clock? I'm trying to get the front bar bracket to be level with the xmember but when I clock it forward one of the axle brackets comes off the axle a little bit

Re: Upper link bar angle
 

It should be ok as long as both sides are the same..making sure the axle is centered side to side and square with the centerline of the frame measured with triangulated measurements..I'm assuming the u bolts are holding the axle in place where it cant move while you setup the 4 link..typically you would want the pivot points at the axle to be lined up vertically but I think you can cheat it a little

Re: Upper link bar angle
 

Garagely, sounds like you are on the right track. I approve. Keep going!

The Fiendish Firefly <<<<<<<< Here is my thread.

Re: Upper link bar angle
 

Thanks will do

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All tacked up... feeling pretty good about it. I'm a little anxious about cutting the tacks off the frame to the axle bc if I did something wrong my axle won't be squared in the frame anymore

Re: Upper link bar angle
 

It looks to me like you need to rotate the axle a little bit to bring your pinion angle down. I see that you have some adjustability in the links so maybe that will be enough. For what you are building I think you only need a couple of degrees there. My experience is with off road stuff so others know more than me here, but I thought I should open the conversation.

Re: Upper link bar angle
 

I would match the output shaft angle, less 1° because you're using poly bushings. At ride height.

If the trans points 5° down, point the pinion 4° up. Make sure the arm brackets are such that you have adjustment either way, in case reality differs from theory (it often does).

Re: Upper link bar angle
 

I tried to match the pinion angles. I was told 3* is optimal. But all I could get out of my tranz is 8* if I jacked up the tranz any more it was putting a lot of stress on my motor mounts. So I made my axle 8* as well but I just articulated my axle up about 10 inches and put it back down and it seems to be ok but after I checked my axle pinion angle again it's more like 7* and when I cycled it up the pinion angle dropped to 0 at 10 inches high

Re: Upper link bar angle
 

Cycled 10 inches up

Re: Upper link bar angle
 

You will have ~some~ pinion change because your upper and lower link arms are not the same length. If they were the same length, the pinion angle shouldn't change at all.

Just optimize the pinion angle for whatever ride height you will run the most. Other heights will be a compromise (good thing you made it adjustable *big*grin*)

Re: Upper link bar angle
 

I would rework your motor mounts to correct that angle a bit. You could pie cut the front of your mounts and raise the trans then weld them back together. Check your clearance between your oil pan and rack and pinion.

How do you plan to get 10 inches of travel up? Bag on bar? That is a lot of travel and could result in a harsh ride with the needed pressure to get there.

I would install my notches now to see the actual angles of everything as you are kinda working opposite. I would also shorten the lower bars in order to minimize the change in pinion angle.

Lastly, from a visually pleasing perspective I would rework the upper front link tabs to make them "flow" better.

Hope this helps.

Re: Upper link bar angle
 

I was just cycling it and I jacked he frame up 10 inches. Not planning on going that high. It's not notched so I can only cycle it one way to check for binds. I am gonna put a gusset up the upper tabs it's not ideal but should work. I don't really know what else to do there. That's where the bars fall.... I should shorten the lowers bars huh? Cuz I was told longer the better and I didn't cut any of them. I read the top bars should be 70% of the lowers

Re: Upper link bar angle
 

I assume you are going to go a lot further down than the 10 inches you went up. Since your upper links are tacked in you already know where your holes are. I would cut up some construction paper and play with the shape a bit until you find something you like. I think a tab that has a 90 degree angle cut into the bottom that spans the upper and side of your cross member would look good. You will need to cut them and drill them yourself. If that doesnt make sense let me know and I will use my crappy paint skills to draw something.

Longer is better to a point. The 70% thing isnt really correct and I would say that your upper bars should be AT LEAST that long. You can make them longer (or lower bars shorter).

Re: Upper link bar angle
 

When designing a short-long-arm "double wishbone" suspension for front suspension, a 70% upper arm is a reasonable ball park (but there is a lot more to it than that).

On a rear suspension, upper arms are only short because there is usually a back seat there.

Re: Upper link bar angle
 

Redid my upper bars. Found my instant center. Now my upper bars would intersect with the lowers in front of the bumper. If they kept going obviously
.. also I decided to back half it bc there was a lot of pitting on the rear rails.

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Back half removed

Re: Upper link bar angle
 

Reworked upper bar tabs. Back half cut off

Re: Upper link bar angle
 

Bars and tabs look a lot better.

Re: Upper link bar angle
 

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