4-Link Thoughts - and Full-Width Axles???

[reddingcruiser]

I'm in the planning stages of putting a 4-link suspension in the rear of my FJ40 and just doing my due diligence. So, I am looking for input on the following items from folks that currently have a 4-link suspension on an FJ40:

• Single vs. double triangulated systems
• Coil springs vs. coil-over shocks
• Any issues related to offset diff as opposed to a centered rear diff. I have a very low mileage Orion t-case but am not opposed to switching to an Atlas, and I am currently building a FF disk brake Dana 60, but have not yet cut the housing.
• Johnny joints vs. heim joints
• Pinion rotation issues related to mount locations.
• Planning on using Ruff Stuff components.

 

[White Stripe]

I would use johnny joints, they are serviceable which is nice and give a little give in them where as heims have no give. Once heims develop play the impact loading will accelerate the wear. Coil overs allow for more fine tuning. I thought of doing a rear 4 link, but I got tired of fabricating when I finished the front suspension so when I got to the rear I just did a soa.

 

[Mace]

On doubly triangulated link designs the axle will walk forward less than one with a singly straight links (for the most part). Other than that, it's preference.

Coil springs and coilovers are essentially the same, but Coilovers are easier to adjust the spring rate on. Packaging is generally easier on Coilovers as well.

Only preference and packaging. Sometimes it's harder to get everything to fit with a offset housing.

JJ (I prefer the RE style joints that screw together) give a bit more "cushion" to the links over a Heim. Personally, I like havong one style at one end of the link and the other style at the other end.

Pinion rotation should not be an issue at all with links.

RS makes burly stuff. I've been using them for almost as long as they have been around. Never been disappointed..

 

[reddingcruiser]

I would use johnny joints, they are serviceable which is nice and give a little give in them where as heims have no give. Once heims develop play the impact loading will accelerate the wear. Coil overs allow for more fine tuning. I thought of doing a rear 4 link, but I got tired of fabricating when I finished the front suspension so when I got to the rear I just did a soa.

I'm SOA with 60 springs, but have been wanting to do a 4-link for years. My new 'day job' affords me some flexibility I didn't have before, so I'm taking the plunge. My preference is also Johnny Joints, so I was looking for some feedback on how long they last vs. Heim joints. Though I do drive this around town occasionally, it is not a daily driver.

 

[reddingcruiser]

On doubly triangulated link designs the axle will walk forward less than one with a singly straight links (for the most part). Other than that, it's preference.

Coil springs and coilovers are essentially the same, but Coilovers are easier to adjust the spring rate on. Packaging is generally easier on Coilovers as well.

Only preference and packaging. Sometimes it's harder to get everything to fit with a offset housing.

JJ (I prefer the RE style joints that screw together) give a bit more "cushion" to the links over a Heim. Personally, I like havong one style at one end of the link and the other style at the other end.

Pinion rotation should not be an issue at all with links.

RS makes burly stuff. I've been using them for almost as long as they have been around. Never been disappointed..

Spring rate is a concern I have and the major reason I am leaning towards Coil-over shocks. The downside to coil-over shocks is the price! What works well real well driving around town empty doesn't work real well on a rig loaded for several days on the trail. Two sets of coil-over shocks would be nice!

I am fortunate I get to the Sacramento area several times a month and can stop by Ruff Stuff when I need to. I've been using there stuff for years.

I know pinion rotation is affected by the length of the upper and lower links and their connection points on the axle housing and frame. I'm looking for specific design information from proven, trail tested setups similar to my current drive train so I'm not reinventing the wheel.

 

[White Stripe]

I'm SOA with 60 springs, but have been wanting to do a 4-link for years. My new 'day job' affords me some flexibility I didn't have before, so I'm taking the plunge. My preference is also Johnny Joints, so I was looking for some feedback on how long they last vs. Heim joints. Though I do drive this around town occasionally, it is not a daily driver.

Cool. Looking forward to seeing your progress.

 

[Mace]

Spring rate is a concern I have and the major reason I am leaning towards Coil-over shocks. The downside to coil-over shocks is the price! What works well real well driving around town empty doesn't work real well on a rig loaded for several days on the trail. Two sets of coil-over shocks would be nice!

I am fortunate I get to the Sacramento area several times a month and can stop by Ruff Stuff when I need to. I've been using there stuff for years.

I know pinion rotation is affected by the length of the upper and lower links and their connection points on the axle housing and frame. I'm looking for specific design information from proven, trail tested setups similar to my current drive train so I'm not reinventing the wheel.

With Coilovers you can set them up for a initial rate and then a stiffer rate after a couple inches of compression. That may work for you. Also, There was a company that made Air bags that went over the coilover. Very sweet setup.

No clue how well they work tho. My 40 on the con was fairly well loaded, and it was not a big deal for the rear coils. Probably not as good at speed, but it was fine while driving. Air bags might be an option as well. They are the most dynamic when it comes to load capacity, and can allow a huge amount of flex.

The amount of pinion travel during articulation is a interesting one. Most of the time it's not enough of a issue to bother with. But very short top links and long lower links can cause the diff to dive badly. The 4 link calculator does a good job of plotting the pinion travel IIRC.

 

[reddingcruiser]

Airbags on a coil over shock. Interesting, and worth more research.

 

[Mace]

No clue if they took off. But I REALLY wanted a set when they came out. IIRC they were cost prohibitive..

 

[reddingcruiser]

No clue if they took off. But I REALLY wanted a set when they came out. IIRC they were cost prohibitive..

Cost prohibitive? Just don't tell the wife.

 

[mano002]

I tried to fit 2.5 x 16" coilovers outside the frame using a 60 series rear end. With this big of a coil, I couldn't get it all to fit width wise. I'm going to 1-tons now. The tire rubbed the coil at full stuff, the coil hit the frame at full bump.

 

[reddingcruiser]

I tried to fit 2.5 x 16" coilovers outside the frame using a 60 series rear end. With this big of a coil, I couldn't get it all to fit width wise. I'm going to 1-tons now. The tire rubbed the coil at full stuff, the coil hit the frame at full bump.

That's exactly why I am looking for input. I am building the Dana 60 to match my stretched FJ60 front axle at 60" WMS to WMS (my, that's a lot of 60's). I should have room for coil overs without rubbing. Centering the diff also makes this easier, which is why I need to decide whether to keep the Orion or put in an Atlas. All things I need to decide on before I chop up the axle housing.

 

[White Stripe]

I remember your setup. I widened my fj60 front axle myself and looked at your rig to help determine if thats what I wanted to do. Have you thought about using a fj80 rear axle? That would not be as heavy as a dana 60 housing. Personally I have found the front axle not wide enough. I would prefer to be more in the 63-65" range wms. I have 2" offset wheels and that gets me the width I want. Also, do you have room under your tub to do a cantilever setup for the coilovers? That would be pretty trick.

That's exactly why I am looking for input. I am building the Dana 60 to match my stretched FJ60 front axle at 60" WMS to WMS (my, that's a lot of 60's). I should have room for coil overs without rubbing. Centering the diff also makes this easier, which is why I need to decide whether to keep the Orion or put in an Atlas. All things I need to decide on before I chop up the axle housing.

 

[Tapage]

Ever consider a ORI setup ..?

I've seen few rolling around here and pretty dynamic load wise and more compact than a CO

 

[Mace]

There is no reason to go to a 2.5" co on a rig like this.

Ori's are a great option tho.

 

[mano002]

There is no reason to go to a 2.5" co on a rif like this.

Ori's are a great option tho.

I would agree. My rig is pretty heavy loaded up, and I got up-sold on the 2.5s. My current plan is to use the 2.5s up front and get a set of 2.0s for the rear.

 

[reddingcruiser]

I remember your setup. I widened my fj60 front axle myself and looked at your rig to help determine if thats what I wanted to do. Have you thought about using a fj80 rear axle? That would not be as heavy as a dana 60 housing. Personally I have found the front axle not wide enough. I would prefer to be more in the 63-65" range wms. I have 2" offset wheels and that gets me the width I want. Also, do you have room under your tub to do a cantilever setup for the coilovers? That would be pretty trick.

I had considered widening the rear axle with the thought that I might put a Dana 60 up front, too. However, I have no issues or complaints with the current width at 60". I did ponder a FJ80 axle, was actually looking for one for awhile and almost bought a non-running local FJ80 to part out. But I already have many of the parts for the Dana 60. As far as the cantilevered coil over setup, I think I'll stick with the more traditional setup. I AM looking at the ORI struts that @Tapage and @Mace mentioned, and I like what I see (except maybe the price).

 

[reddingcruiser]

@White Stripe, regarding the weight of the Dana 60, I have thought about it and came to the conclusion if I was planning on a lot of high speed off-road travel I might be more concerned with the added un-sprung weight. For crawling, I'm not expecting much of a problem, there are plenty of them in FJ40's already.

 

[reddingcruiser]

Business travel has side-tracked me a bit, and obviously this build IS NOT going to happen before the 2016 Rubithon! So, I have a new question related to this 4-link/Dana 60 build, with regards to full-width axles. Among folks who ACTUALLY run full-width axles, what are the advantages and disadvantages you've experienced? Would you do it again?? Truthfully, I know many of the answers, but knowing about something and actually using something can be two different things.

 

[Mace]

From running the con a couple times in both a stock width 60 and a 40 on one tons (and when it was stock with 32" tires), there is no issue with wider axles on the con. At all.. I love the full width axles, and I would do it again in a heartbeat. Strong, low and wide makes for a very stable rig. Not going one tons because of weight is a mistake. Strength comes with a price. Make the rest of the rig light. My 40 weighs in at 4200lbs.