Spring replacement, leveling springs

[Glider]

I have been researching springs in an overall effort to firstly make a smoother ride and second raise the front end to level. I have researched from several sources:

EDIT: The below link is dead.
https://midwestmilitaryequipment.co...v-humvee-h1-front-only-30-lighter-1-5-2-lift/

Springs

4x4Parts Front Stock Coils HMMWV M998 Hummer H1

HMMWV H1 M998 HMMWV Hummer Front Stock Coils

www.4x4parts.com

I plan to run a winch at some point in the future. According to MWM their springs will not give as much lift when a winch is used. They rate their springs as 30%(750lb) less rate than stock and have an overall unsprung height of 13.9". Factory springs are 954 for use without a winch, 1250lbs with winch. If the 4x4 parts ad is correct the factory spring is 13 1/2 tall, only .4 shorter than MWM leveling springs.

The rear variable rate spring does not list pounds but does list spring diameter for H1. The diameter starts at .800(smaller than 954lb diameter) and ends with 1.260(3000lb). Midwest soft spring is 1200 flat rate.

I have read that installing spacers will make the ride worse and agree with that to a point. If you are using spacers to add several inches lift it will make the ride stiffer. If you are adding 1/2 inch the ride will be stiffer but not anywhere as noticeable as 2" spacer.

This is what I am considering. Please point out my errors and keep in mind I am on a budget.

For front, I plan to use factory 954lb springs with 1/2 spacer. My reasoning is MWM is 30% lighter than stock but wont hit height with winch. Factory winch springs are 1250lb. 1250x.666=833lbs. My spring rate will be 22% softer than recommended by OEM with winch. At 70.00 per spring and 30 for a spacer. I'm at 200.00 for front.

Then just go variable rate for the rears. They appear to start very light and taper to heavy. This should have a pretty good ride based on my experience with variable rate springs on other vehicles and will still have the capability to haul a load.

Then I will be studying shocks!

 

[jrtoffroad]

Sounds like a good plan. I think you'll be pretty happy with the front, especially with a shock change. I'm curious to hear how you like the rear. Personally I think the cost of the Midwest springs is nuts. Another good option could be 954lb front springs in the rear if you convert to the welded mount (which gives you the same top spring mount height as the front).

I've been running a Nissan Aramada spring in the rear (626lb/in) that I really like, but just swapped to a pathfinder model for a little more height.

 

[Glider]

What are the drawbacks to the Armada spring?

 

[Action]

a 2" suspension lift does not put 2" spacers on the springs. The wheel is further away from the pivot point than the spring is. So a slight difference in spring height will give a higher lift than the spring height difference.

 

[jrtoffroad]

What are the drawbacks to the Armada spring?

I suppose the drawbacks are having to change the upper mount or maybe add a small spacer to dial in your ride height. Other than that, they're a direct swap and have a nice couple choices of spring rate.

There are 4wd and 2wd springs. The 4wd are longer and have a higher rate (858lbs/in I think) and apparently work well with the stock HD upper spring mounts. These are probably the best option for most.

I went with the 2wd version, which required me to swap the HD cast mounts for the stamped steel mounts to get the right ride height. The ride is awesome and load capacity is decent. The only reason I'm going to a different spring is that I'd like my HMMWV to sit about 2" higher and don't want to risk coil bind if I add a spacer. If you check on Rockauto for a ~2008 Nissan Armada you can see the various rear spring options. The ACdelco springs are well priced and list spring rate and length.

 

[Glider]

a 2" suspension lift does not put 2" spacers on the springs. The wheel is further away from the pivot point than the spring is. So a slight difference in spring height will give a higher lift than the spring height difference.

I was going off the difference between Midwest Military spring height and advertised stock spring height.

I do agree with your statement.

Actually I guess I should ask the question: Will a 13.5" 954# spring and a 1/2 spacer provide similar lift as a 13.9" 750# spring? Also given the same combinations would the spring spacer combo with a winch added ride similiar to un weighted 750# spring.

 

[jrtoffroad]

I was going off the difference between Midwest Military spring height and advertised stock spring height.

I do agree with your statement.

Actually I guess I should ask the question: Will a 13.5" 954# spring and a 1/2 spacer provide similar lift as a 13.9" 750# spring? Also given the same combinations would the spring spacer combo with a winch added ride similiar to un weighted 750# spring.

We need to make a few assumptions with out exact weights, but lets say your HMMWV weighs 6000lbs and has a 52/48 weight distribution. You'd then have 3120lbs on the front suspension. If you assume a 2 : 1 control arm ratio, each spring would see the full 3120lbs force.

With this force, the stock 954lbs spring would compress from 13.5" to 10.3" and the new 750lbs springs would compress from 13.9" to 9.74". Or, assuming the same 2:1 control arm ratio, the new springs would actually lower your HMMWV 1.12". With a 1/2" spacer on your stock springs that difference would increase to 2.12".

So, how are people getting a lift out of the Midwest Military Springs? Probably need to confirm your stock front springs are actually 13.5". I think the rated height of most are 13.36. Also, it could be that Midwest Military Spring rate is under stated. To gain the rated 1.5" lift with the dimensions provided the average Midwest rate would have to be 1094lbs/in.

Please note I am not trying to say anything bad about their springs or that this is the actual rate, just how the math works out with the dimension provided and my assumed weights. I've never seen their springs first hand.

 

[Glider]

Thank you for the insight. Looking back at the 3 links in first post. In the spring link there is a 14" 954# spring that is used on a truck with a winch. Oddy enough there is a 13.3" 1250# listed for all other vehicles.

 

[Glider]

We need to make a few assumptions with out exact weights, but lets say your HMMWV weighs 6000lbs and has a 52/48 weight distribution. You'd then have 3120lbs on the front suspension. If you assume a 2 : 1 control arm ratio, each spring would see the full 3120lbs force.

With this force, the stock 954lbs spring would compress from 13.5" to 10.3" and the new 750lbs springs would compress from 13.9" to 9.74". Or, assuming the same 2:1 control arm ratio, the new springs would actually lower your HMMWV 1.12". With a 1/2" spacer on your stock springs that difference would increase to 2.12".

So, how are people getting a lift out of the Midwest Military Springs? Probably need to confirm your stock front springs are actually 13.5". I think the rated height of most are 13.36. Also, it could be that Midwest Military Spring rate is under stated. To gain the rated 1.5" lift with the dimensions provided the average Midwest rate would have to be 1094lbs/in.

Please note I am not trying to say anything bad about their springs or that this is the actual rate, just how the math works out with the dimension provided and my assumed weights. I've never seen their springs first hand.

JRToffroad, could you please tell me what your thouights would be considering using the following:

06005787 B2 OEM Spring. It is 954lbs straight rate spring with 14" freeheight for front.

Then this armada spring for rear: https://www.rockauto.com/en/moreinfo.php?pk=2607596&cc=1434653&pt=7512&jsn=858

Lets assume 2.3:1 control arm ratio, 6150 gvwr(this includes 150lb winch in front)

I really appreciate everyone's help from the forum and from phone conversations.

 

[jrtoffroad]

JRToffroad, could you please tell me what your thouights would be considering using the following:

06005787 B2 OEM Spring. It is 954lbs straight rate spring with 14" freeheight for front.

Then this armada spring for rear: https://www.rockauto.com/en/moreinfo.php?pk=2607596&cc=1434653&pt=7512&jsn=858

Lets assume 2.3:1 control arm ratio, 6150 gvwr(this includes 150lb winch in front)

I really appreciate everyone's help from the forum and from phone conversations.

I think you'll really like the spring rate of that Armada rear spring and the 16.625 free length should work pretty well with the standard HD mounts.

Without the winch the 14" springs should give you a 1.15" lift (using the 2.3:1 ratio and a 13.5" height for your current springs). Adding the winch in theory would only bring it down 0.18". Although since the winch is forward of the axle centerline, it would be a touch more, but still very little with the 954lb springs. This should be a great option overall.

The next big upgrade would be shocks. The rear shocks on a m1123 are extremely stiff (you have a m1123 right?). Even just putting a set of front shocks in the rear might be a very nice upgrade in ride comfort. Note, I haven't done a in depth comparison between front and rear shocks yet to see if there's any regrets with doing this.

 

[Action]

Has anyone mentioned that the old springs currently in these can be saggy? So, just putting the same spring (new) in could raise the truck a bit?

 

[Glider]

I have a M998. I am assuming that my current springs are a little tired. The front isnt too bad but the rear is very stiff.

Am I correct in the assumption that I will need a slightly stiffer spring for the front as compared to the rear? If the same rate is ok could I cut armada springs for the front?

EDIT: I ordered the armada springs. I have had trouble locating any 954 springs in the 13.6 or 14 length. If anyone knows of a good source please let me know.

 

[jrtoffroad]

Although unloaded the front is heavier, you don't need a higher rate than the rear. I actually like about the same rate on all 4 corners. The armada spring would work well for the front with some trimming (not a lot though, with the lower spring rate it will have a lot more preload).

Does your m998 have the cast HD mounts in the rear or the sheetmetal/ welded style?

 

[Glider]

Welded style. I cant remeber where, but I read someone mentioned they thought Armada in front would be borderline too soft.

 

[jrtoffroad]

Welded style. I cant remember where, but I read someone mentioned they thought Armada in front would be borderline too soft.

Ok. You'll want to trim the front and rear similarly to get your desired ride height.

I believe that discussion was focused on the 4x2 Armada springs that have a 0.77 wire dia. I ran these for a bit on the rear of my HMMWV and they were a little soft. Nice, but ride height was a bit low with a spring length that still allowed full compression without coil bind.

I don't think you'll have an issue with the 0.81 wire springs. I just installed some ram 0.81 wire springs in the front of my HMMWV and so far really like them. Not overly soft, but ride and flex much nicer than the stock 954lb springs. I would choose the Armada spring over the ram though, since I found the ram spring is tapered and has a larger lower ID that does not fit the spring seat well.

 

[Glider]

Armada 4wd 16.5 springs. Post side by side pics when installing later next week.

 

[Glider]

I installed the springs yesterday evening. This was more of a job than I had expected. The 16.5 spring will not fit the rear. We installed it intact initially. When jacking the lower control it lifted the truck off jackstand before we could reconnect. We removed the spring and cut off one round of the coil it did fit with that modification. It was late when finished and i had a 45min drive to get home. My initial feeling from interstate driving is that it does ride smother.

I do wonder if the spring is still too long or if I need to change shock absorbers. There is one spot on my drive that has a pretty good low speed bump. Going over it was bumpy but the compression and rebound felt like it was happening too slowly. Im thinking i need to experiment with shocks. I have in my mind using a bushing that will allow the use of common truck springs.

As far as the DIY part goes. I would not recommend anyone doing this without a good spring compressor. I don't think it would have been possible without one. Even with the compressor it was a challenge to get the spring into the perches.

I will post more info when I have time to do measurements. I didn't get many pictures either. sorry.

 

[jrtoffroad]

Good work. Shocks are definitely your next step. The factory shocks are VERY stiff and won't let the new springs move like they should.

Make sure to "exercise" the new springs some to get them to settle. I like to fully flex out my HMMWV a few times when I install new springs. Typically they'll settle about an inch or so for me.

BTW, when you were installing the new springs, did you loosen the lower control arm bolts allowing it to lower all the way to vertical? I've been able to install 16.5" springs in the rear without a compressor this way.

 

[Glider]

Good work. Shocks are definitely your next step. The factory shocks are VERY stiff and won't let the new springs move like they should.

Make sure to "exercise" the new springs some to get them to settle. I like to fully flex out my HMMWV a few times when I install new springs. Typically they'll settle about an inch or so for me.

BTW, when you were installing the new springs, did you loosen the lower control arm bolts allowing it to lower all the way to vertical? I've been able to install 16.5" springs in the rear without a compressor this way.

I didn't loosen those bolts. I will on front when the time comes! Also if it will settle an inch it should be back at the original ride height based on my brief measurements last night. I did measure before installation but havent been able to park in the exact spot to remeasure. I still have concerns in my mind about it riding too high and not having enough droop when offroading.

 

[Action]

You can chain the jack to the frame to stop from lifting the chassis. The front is easier with the airlift hoops.