80 series spring/weight questions

[adventurebuddies]

97 FZJ80

I have 850Js in the front and 421s in the rear. Front sits at 22.5 hub to fender. Rear sits at the same when unloaded - weight of Kaymar rear, Maggiolina RTT, and 35" spare included. I'm happy with that amount of lift.

Since the truck is not a daily driver and I hate loading/unloading gear all the time, it basically always has the 60L fridge, tools, and camping gear like chairs, grill, lantern, propane tank, etc. With this weight, I loose .5" in the rear and since this stuff is almost always in there, I basically get 22" rear hub to fender and am driving with the rear slightly lower than the front.

A full aux tank, 2 jerry cans on the bumper, 23 gal of water, food, drinks, climbing gear, etc brings me down another inch. So, fully loaded I sag 1.5" in the rear. I was thinking of adding Air Lift bags to the rear to compensate. Do you think that makes sense or would changing springs be more beneficial for the weight I'm carrying. I like the soft ride of the 421 comp springs, though I get some body roll with the RTT and bridging ladders on top. My goal is to maintain ride comfort without sagging so much in the rear and loosing that rear ground clearance.

 

[cruiseroutfit]

Alright, thanks for posting this here. I had asked him to post it here instead of a PM as I think some of the other 80 owners might benefit from this kind of discussion. Many don't even realize there are higher spring rate coils (ala the Comp coils) available from Old Man Emu.

Lets start with your numbers.

22.50"/850J Front
22.00"/421 Rear & 21.00"/421 Rear

Do you want to bring up the front at all? Or just the rear?

Without even plugging your numbers into the calculator I could tell you one great option for your rear dilemma is the 422 coil, its 1" taller than the 421 with the identical spring rate. So no change in ride quality however an instant 1" taller regardless of loading conditions. So when unloaded you might have ~.5" of rake, but that's nothing too major.

I can interpolate backwards using your known spring values to come up with your Front & Rear weights. These are based off of the sample numbers I've been given by customers with builds similar to yours. That said I would love for someone to actually weigh their rig F&R and give me a report back so I can further calibrate my calculator.

I come up with ~2500 lb Front & 3100 Rear for your setup, sounds a bit heavy in the rear (number wise) but given the amount of stuff on your rig I guess its not out of the question.

 

[Wombat]

My 80 has the 44 gallon Long Ranger aux tank, Slee rear bumper with a 305 MTR on the tire carrier, Hanna sliders, 45l Engel, ARB up front with 10K winch, and and AO roof rack. No RTT, but on the rack were two La Fuma chairs with a 60 inch hi-lift on the side of the rack and an EZ-up on the other side. Camping gear for two (tent/sleeping bags/pads) in a kangaroo pouch on the roof as well. Inside were tools and various mechanical spares, plus food for us and the dog.

With this setup and both tanks full of fuel my 80 weighed 7160 lbs with 3260 on the front and 3900 on the rear. I do run OME864 with airbags in the back, but I also unload when I get home. The Engel usually stays, but all the camping gear, tools, and spares are removed, and I usually take the AO rack off and put the hi-lift on the rear bumper.

 

[adventurebuddies]

Thanks Cruiseroutfit. I don't want to bring anything up past the 22.5" because I already sit as tall as I need, I'm sometimes nervous about my high COG, and I don'twant to risk any drive train issues. So, I don't need any adjustments in the front. By the way, the front weight is ARB bumper, M12000winch, 2 batteries, and axe/shovel,hi-lift.

The 422 sounds interesting. My questions/concern with that is body roll. The crossbars, RTT, and bridging ladders on the roof weigh between 200 and 250. I have to take corners pretty slowly (which I'm fine with). Will the taller 422 springs have any effect (positive or negative) on body roll? Will my "normal" weight (without aux tank, jerry cans, food, etc) cause the truck to sit higher in the back than the front with 422s?

Thanks

 

[ginericLC]

I would ditch the J spring in the front and go with a 419 in the front and then go with the 422 Kurt suggests in the rear. Yes you will be slightly higher in the front again, but one of your concerns was body roll with a rooftop tent on it. The 419 will calm down the body roll in the front. Body roll is a combination effect of both front and rear springs so addressing just the rear really isn't going to provide 100% solution.

I ran the 419 in the front of my last 80. It was comparable to a J with a 1.5" spacer after things settled down. So that would give you a height idea.

Another thing to consider if you are worried about stability is to go wider. There are a few wheels you can find in 16x8 with a 3 5/8" backspacing. It doesn't quite give you an inch on each side of more width but it helps tremendously. I hate spacers so I won't even recommend going that route.

 

[adventurebuddies]

I hadn't considering changing front springs primarily for budget reasons - wife already thinks I spend waaaay too much on this rig.

Would it make sense to buy 422s for the rear and brings the 421s to the front? I don't want to go taller than the 850Js in the front for caster and driveline reasons.

By the way, I think there might be small spacers in the front - reddish-purple plastic material at the top of the springs. 850J up front give me 22.5" hub to fender. Does that sound right with or without a spacer?

 

[cruiseroutfit]

My 80 has the 44 gallon Long Ranger aux tank, Slee rear bumper with a 305 MTR on the tire carrier, Hanna sliders, 45l Engel, ARB up front with 10K winch, and and AO roof rack. No RTT, but on the rack were two La Fuma chairs with a 60 inch hi-lift on the side of the rack and an EZ-up on the other side. Camping gear for two (tent/sleeping bags/pads) in a kangaroo pouch on the roof as well. Inside were tools and various mechanical spares, plus food for us and the dog.

With this setup and both tanks full of fuel my 80 weighed 7160 lbs with 3260 on the front and 3900 on the rear. I do run OME864 with airbags in the back, but I also unload when I get home. The Engel usually stays, but all the camping gear, tools, and spares are removed, and I usually take the AO rack off and put the hi-lift on the rear bumper.

Excellent, I'll add your weights to the calculator, that is very helpful. For giggles what are your fender (bottom of plastic fender) to the center of hub measurements?

864 on rear, what on front?

 

[cruiseroutfit]

I would ditch the J spring in the front and go with a 419 in the front and then go with the 422 Kurt suggests in the front. Yes you will be slightly higher in the front again, but one of your concerns was body roll with a rooftop tent on it. The 419 will calm down the body roll in the front. Body roll is a combination effect of both front and rear springs so addressing just the rear really isn't going to provide 100% solution...

Excellent suggestion!

I'm starting to see more and more 80 owners do just this. They get the rear dialed in and use a slightly higher spring rate from coil to counter body roll as well as get rid of some adverse dive on a heavy rig.

 

[cruiseroutfit]

I hadn't considering changing front springs primarily for budget reasons - wife already thinks I spend waaaay too much on this rig.

Would it make sense to buy 422s for the rear and brings the 421s to the front? I don't want to go taller than the 850Js in the front for caster and driveline reasons.

By the way, I think there might be small spacers in the front - reddish-purple plastic material at the top of the springs. 850J up front give me 22.5" hub to fender. Does that sound right with or without a spacer?

You might be able to sell your 850J coils for say $75, spend another $100 and you've got the new front coils.

I'm not at my work computer right now but tomorrow I'll try and remember to run your numbers with the 419 fronts to see what that will do for you height wise.

You can't put the 421's in the front. The coil diameters and free heights are drastically different front to rear on an 80.

 

[Pskhaat]

New one for you:

My 1996 FJZ80 all OME
Front 850J 22.5" hub-to-lip
Rear 864 23.5" hub-to-lip

Unloaded completely except for 2200 atop. When loaded (and I have not measured lately) but the rear I'm guessing is 2-3" down from the front. According to specs (is my maths correct?) 2" = 640 lbs on an 864? That seems actually less weight than expected.

I like a high rear-end, is 868 the way to go? I have not had any issues with articulation in the 864s.

868s have a ΔK of...what...41 lbs/in? Thus let's just assume 640 lbs (which I really think is too little) will help all of 1/3"? Is that right?

 

[adventurebuddies]

Maybe I'm misunderstanding the driveline issues. I have no caster correction or any other changes besides the yellow caster bushings. If I went with the 419 in the front, I think I'd gain an inch over the 850J, correct? With that extra inch, I think I'm now into the territory of needing to make further caster mods and possibly even drive shaft mods. Correct or not?

 

[cruiseroutfit]

New one for you:

My 1996 FJZ80 all OME
Front 850J 22.5" hub-to-lip
Rear 864 23.5" hub-to-lip

Unloaded completely except for 2200 atop. When loaded (and I have not measured lately) but the rear I'm guessing is 2-3" down from the front. According to specs (is my maths correct?) 2" = 640 lbs on an 864? That seems actually less weight than expected.

I like a high rear-end, is 868 the way to go? I have not had any issues with articulation in the 864s.

868s have a ΔK of...what...41 lbs/in? Thus let's just assume 640 lbs (which I really think is too little) will help all of 1/3"? Is that right?

I'll play around with your numbers in my calculator tomorrow. You are correct 864's are 320 lbs/in - per side, so a 2" sag would be 1280 lbs. of additional load. That is a substantial amount there, if your loading varies that much between regular driving of loaded and unloaded, airbags would likely be the best option. I would recommend measuring it next time you load up and see what you come up with. In the meantime I'll try and remember to plug all these number in tomorrow

 

[cruiseroutfit]

...By the way, I think there might be small spacers in the front - reddish-purple plastic material at the top of the springs. 850J up front give me 22.5" hub to fender. Does that sound right with or without a spacer?

Sounds like a spacer to me. It would be worthwhile to measure it. Does it sound right? Well hard to say as all we are doing is comparing know distance measurements (22.5") with known spring rates and calculating what different coils would do in that same position. My calculator makes a guess on the weight, but its arbitrary and just used to compare coils under the same loading. Ideally I would need to know the weights of the vehicle, but we get pretty close this way.

 

[cruiseroutfit]

Maybe I'm misunderstanding the driveline issues. I have no caster correction or any other changes besides the yellow caster bushings. If I went with the 419 in the front, I think I'd gain an inch over the 850J, correct? With that extra inch, I think I'm now into the territory of needing to make further caster mods and possibly even drive shaft mods. Correct or not?

The yellow bushings are likely they OME CA77B caster bushings, good for ~2.5 degrees which relates roughly to a 2-3" increase in suspension. Any more than that and I do recommend investigating more caster, however there are piles and piles of 80 owners running 3-4" suspensions with just the OME caster bushings. Any more than 4" net gain and you really need to look into the driveline upgrade, again plenty run it without but your results may vary.

FWIW the stock fender to wheel center measurement is ~20" for the front. So your 3.5" coils are sitting more in the 2.5" range due to the added weight of your rig.

 

[ginericLC]

I ran the Slee Caster Plates on mine. Landtank on Mud also makes Caster Plates. I never had to run the Double Cardin drive shafts on either of my lifted 80s. I think the drive shaft issue is two parts: 1. Part of it is luck as to what the caster was set at from the factory. There are differences. 2. The condition of the drive shaft and ujoints makes a huge difference in vibration. A drive shaft will wear in one spot after 200k, when you lift it you change the angle and it is no longer in the spot it has been in and that can cause a vibration. I don't like the caster bushing OME sells. They are too hard. They don't allow the suspension to flex enough. They are also a real PITA to get in.