Y-link suspension

FJBen · 08-03-05, 12:45 PM

I haven't seen this before...I know this is a

H*(P but what would be the benefits or bad points of this setup?

bustanutley · 08-03-05, 12:55 PM

its called radius arm. Long arms for jeeps up front. Keeps the geometry pretty good up and down and a taller vehicle

Stock broncos and also fj80s use this in stock form up front

link suspension that is easy to implement up front because there are only 2 mounts to the frame. 4 links up front are hard because of steering, engine, ect. Works well for the most part, anti-squat isn't really much in the equation for the front.

The bad is that the links bind each other and are really hard on the mounts, you should have some sort of bushing on one end of the uppers, but they see quick wear.

woody · 08-03-05, 12:59 PM

actually a pretty standard front link suspension setup...SpaceGhost ran a similar setup in his comp buggy for a year....

note that the design includes a panhard bar.

Running the y-link on both sides does create some inherent bind since the axle needs to twist as it rotates...I know SG broke at least one upper link on his.

IMO, an easier and simpler method is two parallel lower bars, one similar-length upper bar to the passenger side, and a panhard....added strength of more long lengths and less bind during arcitulation.

Note that design uses bushings throughout to absorb the axle rotational movement.

FJBen · 08-03-05, 04:46 PM

So similar to the 80's series...like zach said...hmmm interesting...I understand the whole bind theory on it as well. Nothing that I would want to run...

I'm prolly just going SOA front, 4 link/coils rear.

clownmidget · 08-03-05, 05:14 PM

So what are the disadvantages of going to a 4-link w/panhard in an 80 as in this pic? Especially with respect to driving on the highway at a typical speed. I believe NW Sickboy did these Y-arms on an 80 already (http://forum.ih8mud.com/showthread.p...m+control+arms) but no pics anymore. Thanks for input/advice.
Mike

crap forgot the pic

clownmidget · 08-04-05, 11:28 PM

Come on, someone has to have at least an opinion...

AlaskanWheeler · 08-05-05, 12:03 AM

Some type of sleeve on the axle housing to allow the arms to move independently of the axle would make for an interesting set-up. would be alot easier to do on a dana axle because of the round axle housing.

clownmidget · 08-05-05, 12:44 AM

Yeah, this is close to the same topic in the 80's section on "wristing" the front control arms
(http://forum.ih8mud.com/80-series-tech/54555-wristing-control-arms.html)

Super 70 · 08-16-05, 06:07 PM

I have 4 link front and rear in my BJ70 and like it. Rides awesome on the highway. I had a previous cruiser with Y style radius arms, coils all around, with pins and bushings on the frame and axle... needless to say it doesn't compare to the 4 link... but not bad at the time though... (over 10 years ago).

Super 70

clownmidget · 08-16-05, 09:11 PM

Jeezus, I about fell over when I saw someone actually responded.

Thanks Super70, I would love to have you bring your truck over to my place so I could check it out, possibly buy it...

Did you do the 4-link front yourself?

Super 70 · 08-16-05, 10:04 PM

Well if I was closer, you could take a look.... but California is a fair drive from me. Nope, didn't do the 4 link myself.... had a friend ( professional ) who does this type of thing full time to build it. Of course there are lots of examples out there of poor 4 link suspensions ... but if they are done right... they are awesome.

Here are some old pics of the suspension near the end of the build up.

Mark W · 08-17-05, 01:51 AM

I used an old fashioned, homegrown "5 link" on Tiny. Unequal length upper and lower on each side with a panheard bar. Easy to clear steering and engine componets up front, simple, sturdy and redundant. In theory it can not provide as much movement as some other approaches. But I've got a stupid amount of travel at every corner andcan't even use it all so I'm not too worried about that. It is a bit heavier than some approaches (more links) but weight was not a primary concern (the rig has rockwells and 52 inch tires now so...)

When I had Toy axles and 42s on it the rig ran the highway just fine at 65 and worked the trails like a dream.

Mark...

woody · 08-17-05, 05:47 AM

missed yer post earlier

The 80-series red 4-link above has the same inherent bind issues...as the axle flexes, it also needs to rotate, and running the upper and lower in such a fashion causes the bind.

A triangulated 4-link reduces much of the bind because while there are 4 mounts the axle for strength, two of these "act" as only one point since they triangulate (usually the uppers)...tri the lowers at the frame-side and you eliminate bind more and reduce flex-steer characteristics as well.

Mark is spot on tho, most link suspensions get stupid travel....I've seen too many done wrong tho...too short of link arms, lowers at too steep of an angle, poor bracketry, lack of double-shear mounting, etc.....there is little that's difficult about building/installing one, but there are certain "rules" to try and follow...

Rock Taxi · 08-17-05, 07:47 AM

I like my radius arm front suspension. I am certainly biased about my own rig, but it seems to work reasonably well.

Without a question it was the key to the low ride height I was shooting for (no lift). There is no way I could have gotten a 4 link under my rig without going up a few inches.

Ed

Tools R Us · 08-17-05, 10:19 AM

Super 70, what kind of rod ends are used on your unit and how have they held up?

Super 70 · 08-17-05, 09:19 PM

Joints on my triangulated 4 link are big rig (Semi) steering ball joints.... greasable and used to 80000lbs .... 16 control my suspension. They are overkill but not obnoxious in size or weight.... (slightly larger in size than the Johnny joints) and I have been running my rig hard for a year with absolutley no wear at all on the joints. I drive my truck daily and also do lots of long hunting trips so... sometimes I am on the highway for 12hrs plus only to hit logging roads of 500km plus in one direction. For my needs, I wanted to build a rig that was DOT legal with great road manners and yet as trail ready and buggy like as possible. It gets to be expensive and a hard balancing act to try and build the best of both worlds and of course in the end you can never fully be either so... it is a compromise whatever you do. Enough rambling... the joints are amazing... no complaints whatsoever.

Super 70 · 08-17-05, 09:43 PM

One more shot of the rear suspension....

Tools R Us · 08-18-05, 11:53 AM

Nicely done!

Is the shank on the TRE tapered, did you buy or machine the inserts? What's the applaction for them, or are they genaric amoung brands of semis? What did you pay for them?

Mace · 08-18-05, 12:35 PM

why is the CV at the axle end???

Super 70 · 08-18-05, 02:55 PM

Tools R U,

Don't know the brand of joint... yes, tapered, with the link arms machined. I didn't build the truck myself so some of the detailed stuff could be answered by the builder..... I can put you in contact with him if you want the specifics.

Mace,

That is the exact question we had when I pulled the shaft out of the box.

That was a screw up with the drive shaft shop when I ordered the shafts... we put the rear shaft on the truck with the CV at the wrong end only to move it around the shop and on and off the trailer while in the build process. The drive shaft was changed before the truck went on the road.

The pinion angle on the rear picture has been changed too as in the picture it looks like it is still pointing down. This was pre alignment etc. Airbags are are aired up higher than usual....in the picture and put the truck is sitting a little higher than normal ride height in the rear.

The truck continues to be a constant evolution. These pics were taken april 2004.... truck was on the road in July 2004.

woody · 08-18-05, 02:58 PM

hey, nice lookin star....now, start attachin some pics

sharp rig!

I have yet to see a tie rod end of any sort that wasn't tapered, but there is always a first time....looks like a simple enuf design, I'd be curious on the cost of those ends versus a heim....and the only concern I'd have is the lack of double shear safety when they do finally loosen/break.

clownmidget · 08-18-05, 04:19 PM

Super70, that is some beautiful work. Thanks for the input regarding road manners/front end behavior of the 4-link. What you describe in terms of use is pretty much exactly what you would expect in the western US. 1000+ miles of highway pavement followed by a few hundred of dirt or gravel roads and then a couple of dozen miles of serious trails. I use my truck for work as well so it needs to be at least as safe as it was oem. Let me know when you'll be taking that "drive" over to CA and I'll start cooling the beers

.

Also, have you heard of/dealt with Overkill 4WD shop in NSW? They offer a very interesting 4/5-link front for the 80 series for what seems to be pretty reasonable cost.

Thanks for the pics again, very nice setup.

Super 70 · 08-18-05, 04:47 PM

Woody,

Thanks.

You may be right... not really sure about the taper.

As for breakage or double shear safety, I wouldn't claim to be an expert in that subject matter. I'll leave that to the engineers to debate. As far as I know.... those joints are used as a single point on big rigs and usually have 80000lbs of weight behind them. 16 joints like that on my little rig, that weighs in at a fraction of that.... I doubt greatly weather I will break or see one fail... the other side of that is this truck has a super regular maintenance schedule and gets looked at by my mechanic and the fabricator routinely. Personally speaking, I tend to be very proactive about maintenence and replacing worn parts.

Not sure of the cost difference between hiem joints and these ones. I don't recall them being very expensive...

My dad's truck has hiem joints on his Dodge Skyjacker suspension... they don't look nearly as big or strong. They are not greasable. He is running the coilover suspension from Skyjacker on his 3/4 ton dodge turbo diesel.... which is actually a suprisingly slick kit for the Ford/dodge 4x4s.

kodiak would be able to answer all the technical questions re the suspension as he is the builder.

Here are a couple pics... one early in the suspension buildup. The second of the front end... in the pic the high steer setup is the Marlin crawler kit... I was by OTT recently and ordered a full kit with arms that have a higher rise etc. So I will be switching my steering setup to the OTT full kit in the next week or so.

Gumby · 08-18-05, 05:45 PM

I like the TREs. 16 of 'em would be worth buying a tapered ream.

crawlin cruiser · 08-19-05, 08:36 AM

Silly question,

Ive seen the "y link" suspension many times on the front of trucks. But why is it never used on the rear?

thanks Dan

woody · 08-19-05, 08:43 AM

y-links require use of a panhard....much easier to avoid in the rear with no engine to clear....and that panhard frequently wants to end up where the fuel tank sits....

y-links are notoriously pathetic for antisquat values under accelleration...some of the Early Bronco crowd has run their C-bushing arms all around with coils with limited success, but a standard VV or XX 4-link will work better.

(my rear suspension is essentially the VV style)

clownmidget · 08-21-05, 12:28 AM

Ok, Woody, then how important is the rear panhard on something like a 80-series strictly off road? It appears on a lot of these custom rear 4-links there's no panhard, but when I finally got around to installing an adjustable one on my 80 my rear axle was offset 2 inches. Now maybe it was the stock length panhard pulling it out like that and just removing it would have let the axle center???? Interested because obviously there's a downside to having that panhard, even adjustable, off road under articulation.

Neat stuff. I just realized that the 70 doesn't have a panhard in the front either!?!? Thanks in advance for clearing up the 4-link vs 5-link pros/cons.
Mike

Tools R Us · 08-21-05, 01:56 AM

Quote:

Originally Posted by clownmidget

then how important is the rear panhard on something like a 80-series strictly off road? Mike

The parallel link setup in the 80 uses the panhard center the axle, the links are not setup to take sideloads. A triangulated 4 link setup is designed to take sideload so the panhard is not needed. The easiest way to eliminate the panhard on the 80 would be by replacing the two top links with a wishbone type link?