How well-designed is the Duff 4 link?

[destinbeachman]

I'm currently running a set of WH 5.5 springs in the rear, behind a 351, C4, Terra low D20 to a locked 4.88 9" and 37s, and am tired of the spring wrap, and worn u-joints. I've decided to link it, and am trying to decide whether to build or buy. I am a good fabricator, but work overseas, and don't usually have much time at home. So, that time has become increasingly valuable.
How does the Duff rear work out on a calculator? Any reported problems? I do drive my rig a lot on the street as well, and would run an anti-rock bar, and fairly stiff shocks.
Every 4 link is a compromise, of course. I'm looking for input based on experiences, and don't expect any absolutes, so no worries.
In any case, I'll either have the Duff setup waiting for me when I get home, or PP or RS basics and make my own. If the Duff setup works okay, I'd rather go that route.

 

[KyleQ]

I've had WH 5.5 rear leafs for years and I absoutly love the way they ride and flex - but I know what you mean about spring wrap and u-joint failure. I didn't feel like I needed the extra articulation so I went with a Ruff Stuff anti-wrap bar. I lost all of that crappy feel and no articulation. Unless you are dead set on linking - I would highly suggest their wrap bar.

 

[destinbeachman]

I've had WH 5.5 rear leafs for years and I absoutly love the way they ride and flex - but I know what you mean about spring wrap and u-joint failure. I didn't feel like I needed the extra articulation so I went with a Ruff Stuff anti-wrap bar. I lost all of that crappy feel and no articulation. Unless you are dead set on linking - I would highly suggest their wrap bar.

I considered several anti-wrap devices. But, in for a penny, in for a pound. The 4 link provides more advantages than just keeping the pinion in line. I think, for most, that the anti-wrap devices are fine for most users, but not for me in this case.

 

[beaux312]

I have the Duff setup. I LOVE IT, It is solid as can be, I have beat on it very hard and had NO issue at all. I even dumped the cluch on pavment, my axle didnt like it. On the street it does take a second to get use to. But real smooth and tracks straight. Hope this helps.If you ever head north a little you can come look at it.

 

[Monster Mike]

Great time to ask about the duff 4 link. it has evolved into its 3rd revision since it first came out. I have been working hard at making it a more compatible with other axles. I'm just about to build the first batch of 4 links that will work on full width 9'' F150 axles


as of right now the 4 link only works on a 9" early bronco axle and we also have a 1 ton 4 link truss that works on a stock rear dana 60 and 70, 10.25 and the 14 bolt


For just over a year now we have offered the new duff 4 link with a 3.5 suspension offering an even lower center of gravity coupled with The lower axle links being set up at the axle center line which provides better stability (amongst other things). this kit also works with a 5.5" suspension. It does require a 2" body lift to mount the inboard shock hoop and the coil cups

your exhaust will have to be modified as well.

 

[destinbeachman]

Mike, my rig has a 3" body lift already to run the front shocks(has Duff long arms). I have heard about the 3.5 4 link and it's improved ride. I was planning on using BF or RS adjustable height upper cups anyway, so wondering if those, plus 5.5 coils from you guys, would get me where I want to be with the 3.5 link kit. I take it that it works just as well with the taller lift-maybe even better with the added headroom?

 

[Amac70]

so how long till the full-width 9" version is available, i've been thinking about this a lot the last few weeks. doing 4 link rear with ori's. if you need a guinea pig??

 

[NYLES]

Cant wait till mine gets here!

 

[Monster Mike]

Mike, my rig has a 3" body lift already to run the front shocks(has Duff long arms). I have heard about the 3.5 4 link and it's improved ride. I was planning on using BF or RS adjustable height upper cups anyway, so wondering if those, plus 5.5 coils from you guys, would get me where I want to be with the 3.5 link kit. I take it that it works just as well with the taller lift-maybe even better with the added headroom?

The 4 link uses our stock bronco height coils for a 3.5'' lift. then we offer a kit that raises the coil retainer up 2'' for guys who run 5.5'' in the front. with your adjustable coil cups and an extra inch of body lift. its possible you could run our 3.5'' coils instead of the spacer kit.

by added headroom you mean the extra inch of body lift right?

 

[Monster Mike]

so how long till the full-width 9" version is available, i've been thinking about this a lot the last few weeks. doing 4 link rear with ori's. if you need a guinea pig??

it should be available by the middle of march

 

[destinbeachman]

The 4 link uses our stock bronco height coils for a 3.5'' lift. then we offer a kit that raises the coil retainer up 2'' for guys who run 5.5'' in the front. with your adjustable coil cups and an extra inch of body lift. its possible you could run our 3.5'' coils instead of the spacer kit.

by added headroom you mean the extra inch of body lift right?

Well, by added headroom I meant the extra space above the housing and upper link brackets.
Which set of coils would provide the most flex? 3.5s or 5.5s?

 

[outofphaze64]

On graigslist in mi

http://saginaw.craigslist.org/pts/4876470584.html
Here is a set up 1200. Not mine

 

[Monster Mike]

Well, by added headroom I meant the extra space above the housing and upper link brackets.
Which set of coils would provide the most flex? 3.5s or 5.5s?

Suzy's crawler has 3.5" coils in the front and stock coils in the rear with 40" tires. She can get a rear tire about 50" vertical before another tire will lift.

There is such a thing as too much flex. You get to a point where the bronco gets too floppy and is unmanageable above 45 mph. Our theory is go as low and as wide as you can. Suzy's crawler is 79" tall and the track width is 85" wide.

The 5.5 will give you more tire clearance and you won't have to remove much of the wheel opening (if any) and the longer coil will flex more but not compress as much

 

[mavereq]

If you're going to run could in the rear, you'll have to notch your fender wells if you want to use adjustable coil buckets. There isn't much room under them. I like taller buckets and longer springs so they don't limit your travel. I also recommend the duff lower spring mounts. They allow the spring to pivot away from the mount so you can get some extra droop.

 

[mavereq]

Could = coils.

 

[Yeller]

IMO dollar for dollar is a great way to go. It fits, it works and the geometry is pretty good. unless you have a LOT of suspension design experience it would be very difficult to do something that works better and even at that it would be marginal let alone something you can have installed in a long weekend.

 

[destinbeachman]

IMO dollar for dollar is a great way to go. It fits, it works and the geometry is pretty good. unless you have a LOT of suspension design experience it would be very difficult to do something that works better and even at that it would be marginal let alone something you can have installed in a long weekend.

Right on. Thanks for your opinion. That's what I'm thinking also. I have a friend who has been raving about the ORI struts, after installing 2 pairs on his Mog-equiped ride, so I will take a ride with him before deciding on coils or not.

 

[Monster Mike]

Update on the Duff 4 Link. Over the last year I've made some more changes to the truss, frame mounts and upper links to make the install process even easier.

We also have the Full Width 9" 4 Link available now.

We just finished approving a design on a rear sway bar that will be offered as an add on. It will work on all of our 4 links and hopefully be available early next year.

http://www.dufftuff.com/SearchResults.asp?Search=4+link&x=0&y=0

 

[68rustbucket]

Mike,
What if I want to move my rear axle back 6"? Could I do this with your 4 link? Would the geometry still be right? If not, what would need to be done to correct it?

 

[Monster Mike]

Mike,
What if I want to move my rear axle back 6"? Could I do this with your 4 link? Would the geometry still be right? If not, what would need to be done to correct it?

One of our customers is in the middle of trying that. He already has our 4 link and is extending his wheel base. As long as The Frame mounts can be slid back you should be fine. I'd have to look at the frame and see if there would be any issues doing that.