The leaf springs in my BJ73 are fairly flat. I have added about 150lb or so to the nose of my vehicle with the addition of a strong front winch bumper and brush guard. I now have about 1.5" between the front bump stop and leaf spring, and 2.5" between the rear bump stop and leaf spring......I am considering some OME 2" lift medium springs. I am also considering air bag suspension. By this I mean removing all leafs but one on each corner used for locating the axle and adding air bags at each corner(individually inflated). From a simplicity/durability standpoint I see new leafs as the best answer. From a ride quality/adjustability standpoint the air bags seem attractive..............................Any opinions/experience?
Air bag suspension?
- Thread starter robmobile73
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There are aftermarket manufacturers that do air bag suspension retrofit systems for full-size trucks and Jeeps. Speaking as someone who has worked in the consumer aftermarket, I HATE them. Not saying the end result doesn't ride and drive well, but it combines two of my least favorite things for the average auto enthusiast: a complete scrapping of the factory style suspension (in this case, having to install a link suspension that the vehicle was not designed for) and the complexity and durability issues associated with air bags.
Having worked with everything from daily drivers to race cars, I have become a big fan of utilizing the suspension style that your vehicle was designed for from a reliability standpoint. I am also a huge fan of leaf springs. Leaf springs don't have to suck, you can get 90% of the performance and ride quality you get out of a link style suspension with the simplicity of leafs, you just have to plan it out and spend a little money to get it right. I have OME mediums on my BJ74 and while the shocks are lacking in the handling department, the ride is surprisingly good, at some point I'll do custom leafs but this is pretty good for the time being.
Then there are airbags. I can recall multiple times when I worked at a shop that I had to deal with the nightmare of repairing a broken Kelderman air suspension on some dumb show truck that came in on a flatbed, and I've also managed a couple of installations. You're multiplying the complexity of a custom link suspension by the complexity of an air suspension. No thanks. Now, I will say that getting some big dumb Ford on 42" Super Swampers to ride like a Cadillac and handle well is pretty sweet, but the ROI on the cost, time and maintenance on something like this is not worth it in my book.
If you are one of those that just need to do a custom suspension and want ride and infinite adjustability, you can look into ORI struts. At least once it's dialed it will be robust. I have a lot of experience with ORIs and the stability and ride quality you get out of them is unsurpassed. Again, I would NEVER do this on my BJ74 even if I wanted to go all out, I'd stick with leafs, nice shocks and some sort of performance bump stop, but it's more reliable than air bags.
In the end do what makes you happy, what I or anyone else thinks doesn't matter. If you're gonna do something big and custom, do it right and don't cut corners. Good luck with whatever you decide!
So you changed the original leafs of your BJ74 to medium OME leafs? Are you talking about the rear axle or both axles? How's the ride comfort compared to a full coil suspension J70, if you have any experience with that? If you had to do a full rebuid of a J73/74 with rear leaf springs would you chose custom leafs or a coil conversion for the rear axle? (with ride comfort in mind, not simplicity or reliability)
None of the upgraded leaf suspension trucks come close to ride like the ones with coil springs , Old Man Emu, Dobinson ,TJM, Terrain Tamer are all good upgrades for stock leaf springs but the coil sprung models give a way smoother ride and much better articulation offroad . If you need to carry heavy loads or pull heavy trailers then leaf sprung trucks are your best bet, everything has a time and a place.
Do you know any good coil conversion tutorial / guide? I've seen a thread by user SNLC on his rebuild of a PZJ70 that contains the conversion, but I guess it does't hurt to have more info.
I'll agree with @MyCruiserisaHogBeast on the leaf springs. My BJ74 rides actually pretty nice for a lifted leaf spring setup. I think my lift is 2.5~3" although I have no idea how to determine that short of getting measurments from people with other lifts.
I have some wallow as my shocks are nearing end of life, but the ride down the highway is great. I'm debating which shocks to get, Ironman Foam Cell Pro or Bilsteins.
I'm not using this rig as a super flex machine, and if the ride quality stays the same or better with new shocks, I will be completely happy.
My 80 series rode really nice lifted and I don't expect the BJ74 to be that nice, but I will say it does ride pretty good. There are TONS of other things I could spend money on my rig that would be better than the investment to a coil/link setup.
I have some wallow as my shocks are nearing end of life, but the ride down the highway is great. I'm debating which shocks to get, Ironman Foam Cell Pro or Bilsteins.
I'm not using this rig as a super flex machine, and if the ride quality stays the same or better with new shocks, I will be completely happy.
My 80 series rode really nice lifted and I don't expect the BJ74 to be that nice, but I will say it does ride pretty good. There are TONS of other things I could spend money on my rig that would be better than the investment to a coil/link setup.
- Thread starter
- #9
I really appreciate all the replies from everyone. I had not considered dropping leaves and adding coilovers that is interesting and simpler than air bags. I have no intention of doing any sort of custom link suspension. I'll try to explain the Idea again here.
Remove all the leaves except for the single leaf with the eyes on each end. That leaf locates the axle when holds it together. Rubber bump stops will be removed. Airbags will be placed between the frame and the top of the axle where The bump stop was originally with a simple Schrader valve on each airbag.,................ The downside I see in this right now is possibly axle wrap and wheel hop in sand.
Remove all the leaves except for the single leaf with the eyes on each end. That leaf locates the axle when holds it together. Rubber bump stops will be removed. Airbags will be placed between the frame and the top of the axle where The bump stop was originally with a simple Schrader valve on each airbag.,................ The downside I see in this right now is possibly axle wrap and wheel hop in sand.
Or just get a LJ/RJ/KZJ73 that already has coils , if you are gonna spend an entire day trailriding it makes a world of difference vs riding in a BJ/HZJ 73
True. I remember the first time I wheeled my 80 series after years of 40s/55s. Wow, super comfy.
This truck came with a brand new OME suspension. My previous HZJ73 had stock suspension with shackles with some sort of weird garbage shocks that came on it from Japan, so I do know the difference between factory and what I've got.
I've said this to so many people, but I mean it and I speak from experience (including my last one, where I didn't listen to my own advice and build a gigantic rock crawling overloading daily driving Cummins powered Land Cruiser of my dreams that consumed transmissions, money and tears... and nearly my marriage....) -
if you plan on daily driving, "overlanding," road tripping, etc I would never recommend stepping away from a vehicle's factory drivetrain unless you have the skills and time to really dial it in and have the luxury of trail and error, fix and repeat. Even if I had infinite money I'd keep the leaf springs if I wasn't going huge. Matter of fact, if I had infinite money I'd just buy a vehicle with factory coils on it if that's what I wanted.
Would I link a Land Cruiser using crazy race car parts if I was going to throw it on 40" tires and trailer it everywhere? Sure thing! But I don't have that luxury right now, 99% of enthusiasts don't. The fact of the matter is there are diminishing returns on that level of customization. With a good driver you can get anywhere you would want to take a full bodied rig with 35" tires, lockers and gearing.
I actually have spent a bit of time in a KZJ78 with a fresh Dobinson's kit and I'm not gonna lie, it was sweet. But it was a light duty truck and felt like it. I have owned a clean FZJ80 and coils and it was great, too. Definitely felt heavy like my BJ74.
You would have have to have a zero rate leaf spring built specifically designed to handle this sort of thing. Axle wrap would destroy this set up, you would have to install some sort of ladder bars or bam bar to keep from blowing stuff up. Everyone knows someone who has gotten away with some redneck engineering but that doesn't mean you will. I'm sure it can be done "right" but I certainly wouldn't bother. Grab yourself a nice leaf spring and spend some coin on a really good set of 2.5" big boy shocks and you'll be in good shape. If you want coils, I might seriously recommend just grabbing yourself something that came with coils from the factory unless you want to do it just for kicks. You'll find diminishing returns on something like this real quick. My $.02 says so anyway
- Thread starter
- #13
This is why I enjoy this forum....I have alot of unconventional ideas, but I am very analytical and "think out loud" bouncing my ideas off of other people.................I think you are right. I already have some bounce and wheel hop when digging along in wet sand. ...............On the coilovers and on air shocks I think the shock mounts would have to be beefed up substantially as they are not designed to "support the vehicle".You would have have to have a zero rate leaf spring built specifically designed to handle this sort of thing. Axle wrap would destroy this set up, you would have to install some sort of ladder bars or bam bar to keep from blowing stuff up. Everyone knows someone who has gotten away with some redneck engineering but that doesn't mean you will. I'm sure it can be done "right" but I certainly wouldn't bother. Grab yourself a nice leaf spring and spend some coin on a really good set of 2.5" big boy shocks and you'll be in good shape. If you want coils, I might seriously recommend just grabbing yourself something that came with coils from the factory unless you want to do it just for kicks. You'll find diminishing returns on something like this real quick. My $.02 says so anyway
Thankyou all for the replies.