Questions for the link gurus

marvilusone

marvilusone

Well-Known Member
Joined
Oct 21, 2007
Location
Charleston, SC
Here's the setup I have in mind for the Ranger. Kind of a wristed radius arm type setup. The y link will be on the driver side mounted vertically. The arm for the passenger side will be just a single straight arm. The yellow dots are JJ's. Overall length of the links will be around 30". Main link tubing is 2.375 OD, .4375 wall, 1.5 ID.:D The upper part of the y will be 2 OD .25 wall, 1.5 ID. I would just build a traditional 3 link but I don't have the space. BTW I will be running air shocks and full hydro.

picture.php


Questions
Should this setup perform well?
What problems do you see with it?
Should I use bushings in place of any of the JJ's?
Should I keep my track bar totally flat?

If it would benefit the setup I can extend the links up to 44".

I'm lost at what to do on the front for links as I have next to no space. This is all I have been able to come up with.
 
You will not need the JJ's on the axle end of the Y arm they will be useless because with the UL mounted to the LL it will not alow the two joints to flex all your flex will come from the frame end of the link. I would use a fixed poly on the lower and adj poly on the upper so you can adjust the pinion angle.

From my own personal experience I would make the links as close to the front driveshaft length as you can so you have minimal spline travel.

Since your running full hydro yea I would try to get the panhard as flat and long as you can.
 
x2 on above.....

typically the longer the links the better it will perform... you want the trackbar to be parallel with the axle/ground (flat/horizontal) halfway through the suspension travel... so if you run very little uptravel (like most with airshocks) the track bar won't be flat at ride height...
 
So I need to............

make links longer
adj bushing @ top of y
fixed bushing @ bottom of y
JJ's everywhere else or just at the frame ends?

I follow you on the track bar. I'm only planning on having around 4" of up travel so I'll need to get the links built then articulate the suspension to find my mounting points.
 
JJ's at frame end of both and JJ at axle end of passenger. Then as far as the Y end goes you could do it a few different ways. You could just weld the upper link to the lower where they meet or you could use a joint. If it were me I would say prob use JJ frame end, fixed poly axle end lower, fixed poly axle end upper, and 3/4 heim where upper meets lower so you can adjust pinion. Thats probably the cheapest and easiest way to go about it and still have full adjustability and as far as the upper part of the link goes you can build it either way like this or like I said earlier it wont make much difference. You just dont need to waste the money on JJ's for the axle end of the y cause they will be useless.
 
Gotcha. Now I can finally start on building some links and brackets. I also just figured out a way to tuck in a double tri 4 link but I can't figure out how to post a screen shot of the program to get feedback on my #'s. Even though I got it to clear the frame and crossmember I think I'm going to run into DS clearance.
107% AS
15" roll center
9 degree roll axis angle
 
Have you thought about running parellel upper links and triangulated lowers. In other words make your upper link mount on the outside of the fame, and make a crossmember under the TC output where the lower links converge. Its kinda the reverse of how most people do it but makes alot of room cause no links have to be run up inside the frame area. I've see alot of the rockwell guys do it that way. The biggest problem is that your axle has to be wide enough that that the tires don't hit the upper link at lock.
 
Unless Im missing something from this picture, the problem you have is the lower engine cradle. and maybe the forward part of your frame rail where it drops down.
Cut it all off. Make a simple tubular cradle and you can cut off the frame and make new where you want it.

ai237.photobucket.com_albums_ff7_marvilusone1970_100_3412.jpg
 
The engine cradle is going to be trimmed even with the bottom of the frame and then plated in. Even with that done the sump of the oil pan sits right in the middle of the plane of the lowers. I have found enough space to fit everything in but I can figure out how to post a screen shot of the link program.
 
The thought has crossed my mind a few times but I don't know too much about them. It's on my list of things to research but I havent gotten to it yet. Can I run a wishbone setup and eliminate the trackbar? I'm pretty sure I can make room for it. Whatever style upper links I would run would need to be 30" or less. I'll look again tonight but I believe thats about all the room I have to work with on my uppers before I run into the transmission. All my clearance issues are because I don't want any extra lift. I have plenty of clearance for the tires its just getting the links in there with it so low.
 
to post a screen shot, open up the program/file, hit PRNT SCRN button, open up Paint or other image software, PASTE, save image, post here...

The AS number you posted earlier seems high, so you can make links longer, or change their spacing to get that number down...
 
Yea a wishbone 3 link will let you eliminate the panhard bar. One good thing about a wishbone is that you dont have to make it symmetrical. As long as your frame pivots are in the same plane and spaced as far apart as possible and the axle end is in the center of the axle you can make it any shape from there. It could be a basic triangle or anything you need it to be to clear the crossmember or the oil pan. Look into some of the desert race guys front upper control arms. They have to build all kinds of crazy shapes to clear 4" coil overs or big by-pass shocks. I think the most common shape is a J which in your case would probably work well. you could make it hook around the passenger side of the oil pan to eliminate having to worry about exhaust and driveshaft clearance.
 
I'm going to take a good look tonight and see how short I can get the engine crossmember and make some clearance for a wishbone to go around each side of the engine. I will have to un the frame ends of all my links a little lower but it should put them almost level with the ground. Thanks for all the help so far. I literally gave myself a headache trying to figure everything out last night.
 
Well after alot of measuring and another headache I've come up with this. The wishbone is going to be the lowers and the uppers will be running from the knuckles back to the outside of the frame rails. Here's the numbers.
picture.php
 
Few problems with this. First I assume your running larger that 32" tires?

The idea with a wishbone is to use it for your uppers to get around the oil pan. 99% of link suspenions uppers converge at the axle end and lowers converge at the frame end.

Me thinks you need to do some more measuring.
 
Are you doing these calculations as a front link suspension or rear? In the rear when you launch the pinion tries to raise up and in the front it tries to go down which means it wont do what your expecting. I think with front susp anti-squat is actually referred to as anti-dive which relates more to braking than power transfer which would change everything.
100% anti-squat means that the rear suspension 100% counteracts the weight transfer to the rear on acceleration. IMO if there is any "true" A-S in the front then you would lift the front alot even if you had 100% in the rear, and you would dive alot on the brakes I'm not sure thats true but I think that's how it would work.
If the calculator your using is for rear suspension then all the squat #'s your getting would actually apply to braking not acceleration. There are so many things to account for when you build a link susp it's not hardly worth worrying about. I would build it how you can with the room you have as long as your links don't bind you'll be fine.
 
My design is based off of the suggestion in post #7.

I'll be running tires somewhere in the 39" range. All my measurements that are entered are taken from how it sits on the 32" rollers. I've measured forever trying to fit the wishbone around the oil pan, motor mounts, starter and driveshaft. Without running more lift or raising the drivetrain it will not fit and keep enough link end vertical seperation at the axle. Even with running my lowers under the axle to get the wishbone to fit up top the upper axle mount will only be 6" above the lowers. I've even lifted it an additional 2.5"(that I don't want to do) today to try to get more clearance. Belly height once all said and done will now be around 27" which is more than enough.
 
I don't see any problem with you using a wishbone for the lower. It will still function the same way as it would being the reverse, as long as you keep the lowers longer than the uppers your fine. Im not knocking you csudman but nobody says you have to be like everyone else it's always nice to see people do stuff different.
In post #7 I had actually meant for the links to converge at the frame end not the axle end but I don't think there is a prob with how you have done it. Lets see how it works.
 
One thing I just noticed is that your pinion may interfere with with the lower link on down down travel if you do it the way your talking about in. Just something to think about.
 
I've tried every way to try to get everything to fit the "traditional" way and it just won't do it. Do you think there will be too much load on the single axle joint of the wishbone? I can split the wishbone and run seperate lowers if it would be better. Where can I find a front link calculator? Money is limited right now so I'm trying to get everything figured out the best I think I can so I only buy what's needed.
 
MarsFab said:
One thing I just noticed is that your pinion may interfere with with the lower link on down down travel if you do it the way your talking about in. Just something to think about.
Click to expand...
I checked that and since my D50 is a HP and offset so far to the driver side, everything clears according to my measurements. I could be wrong but trust me I'll double, triple and quadruple check everything before I begin to actually build it.
 
I cant find a front calculator I've tried and from what I can tell nobody can there's not one out there. Which is suprising considering how many people are doint it now. I can't imagine that a JJ wouldnt be strong enough but use one with the biggest shank you can get. For security I would go with 2 lowers and make it a 4 link though. Keep posting pics of the build I want to see how it turns out.
 
If it just won't fit, Do a true 3 link w/ panhard. Simple to build and proven to work. I would hate to spend all that time and money, and find out your front suspension flat doesn't work.
 
Looking at your calc there, Id say 27% is too low, you will probly want it up around 60-70%... you can do it by having less vertical separation on the frame side... That calc will work in the front and rear, it just means a little different depending on which end... In the front it will actually be anti-dive or anti-squat moving in reverse... the closer to 100 it is the less it will want to dive when on the brakes... over 100 it will not dive at all... Also you want to run the numbers with the tire size your going to run, because it will make a difference...

Also, the links lengths will affect axle rotation when cycling... to keep the caster the same throughout travel, the links need to be equal length... to keep the pinion pointed at the tcase the whole time, they will need to be different lengths...

I would use 2 links on the lower... if you land on a rock with that lower it'll probly break even a big joint...
 
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