How good can a full-size solid axle suspension be?

[Metcalf]

Sure, off the shelf coils would work. Some vendors even off a spring exchange (with modest fee) if you need to change the rate in the first 30 days.

It should be pretty easy to pick a good spring rate though. Start with what you got, do the load calculations for the ideal rate. Then pick the length which gives you the desired ride height. Should be plus/minus 1/2" if your weights are accurate.

Either way you can get spares if needed. Factory design might be easier, but either way you can get them in a few days in the unlikely event you break one.

Shock travel also figures into it, specifically total stroke and what kind of up-down bias it will have. Also how much preload I want to try. Also the sprung weight should be pretty much at a final number ( which it isn't yet ). An 'ideal' rate sounds great, but I don't think it is THAT simple really. I think being able to swap in off the shelf coils of a known rate and length could help which is why I suggested it. I think building in a little wiggle room as far as adjustment for height/preload could be good.

 

[Metcalf]

I would venture to guess that because the art of making custom suspension is basically gone in the last few years. Used to be ample competent custom spring makers.

I've wasted $2k+ in the last couple years trying to get custom springs made for my Tundra, from both Deaver and from Boise. Both once reputable shops. Now just cranking out premade stuff.

I know you're talking coils, which are easy to swap, but when youre a one man show and do all youre own work, swapping out 4 different sets of LEAF SPRINGS that incompetent morons cant even get close to right, your faith disappears.

My .02

Thank you for the honest post. This is one thing I have been running into when talking with vendors these days. Many can't even a communicate well or consistently.

I also have to go through the custom rear spring process also.

 

[nitro_rat]

I'm not against custom coils. If you have any vendors that you have experience with I would love to hear about it.

I used to have springs done by a shop in Houston that's gone now. I know some guys who have had good luck with Coil Spring Specialties, mostly car stuff. Usually arond $250 a pair IIRC. At that price point you could do a couple sets if necessary I would think. They were pretty good at nailing ride heights though. If it's something odd they might request you send in a spring for them to measure but I would bet they have the specs for your truck already.

There are spring charts online for the Ford truck spring codes. You can find your spring code on the sticker in the door jamb. There might be a factory option that will work for you depending on what final ride height you want.

 

[mk216v]

Thank you for the honest post. This is one thing I have been running into when talking with vendors these days. Many can't even a communicate well or consistently.

I also have to go through the custom rear spring process also.

Ha, so true, and so sad! Customer service at most vendors has gone to ********.
Deaver did them for GG here; https://expeditionportal.com/featured-vehicle-goose-gears-overland-f-350/ (I plan to get the same/similar from Deaver, if my rear axle weight is close to GG)

 

[Metcalf]

I used to have springs done by a shop in Houston that's gone now. I know some guys who have had good luck with Coil Spring Specialties, mostly car stuff. Usually arond $250 a pair IIRC. At that price point you could do a couple sets if necessary I would think. They were pretty good at nailing ride heights though. If it's something odd they might request you send in a spring for them to measure but I would bet they have the specs for your truck already.

There are spring charts online for the Ford truck spring codes. You can find your spring code on the sticker in the door jamb. There might be a factory option that will work for you depending on what final ride height you want.

Yup, I posted the coil chart a few pages back. The ford spring rates seem incredibly stiff for the sprung weight numbers I have. That is the issue. The ford rates don't make much sense to me really in overall planning unless the front end is loaded down a ton. The other thing I need to measure is shock travel up/down to see what the bias is and how that changes things vs total shock travel on a stock truck ( which is pretty limited on the front end )

 

[CodyY]

Legit question, what's the cost difference in coilovers and having custom coils done AND dealing with not getting them right the first time?

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[CodyY]

Yup, I posted the coil chart a few pages back. The ford spring rates seem incredibly stiff for the sprung weight numbers I have. That is the issue. The ford rates don't make much sense to me really in overall planning unless the front end is loaded down a ton. The other thing I need to measure is shock travel up/down to see what the bias is and how that changes things vs total shock travel on a stock truck ( which is pretty limited on the front end )

My v10 on 37s with my 6yo, a full tank of gas and rtt on the back

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[Metcalf]

My v10 on 37s with my 6yo, a full tank of gas and rtt on the back

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A good example of the issue.....it is amazing the difference in weight on similar vehicles ( and how that effects spring rates )

Here is mine.

 

[Metcalf]

Legit question, what's the cost difference in coilovers and having custom coils done AND dealing with not getting them right the first time?

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From my evaluation of things, at close to stock height, there isn't room to package a coil-over ( with very much travel ) without going pretty far into the engine bay on a custom mount. I'd rather not go that far. Carli has an decent mount if you can deal with more overall height.

Personally, I think a coilover tends to be a little squeaky and clunky with the metal on metal rod end mounts. Good for being strong, not for being quiet in the NVH department. I think retaining bushing type mounts would be the 'best' way to go all around. Fox and King both have 2.5 options. Fox has a few things in 3.0 stuff, but not a wide selection. The tipping point between things in general for good to great shocks seems to be in that 2.5 to 3.0 range also.

 

[jwpnrp]

Metcalf your builds are always educational and fascinating.

I don't post much as my builds are pretty basic and progress is approximately glacial (started collecting parts trucks and parts on Maui 14 years ago, shipped basic bones / barely drivable roller to Washington 2015, just got front axle rebuilt to have four-wheel drive this winter, next step is front coil conversion and rear airbag mounts with integrated gooseneck hitch). Work truck that's comfortable ( on / off road) empty and with varying loads is what we are working towards, all though much older suspension plan is similar. 80s F350 Mechanical 7.3 manual trans CCSB, early 80s coil spring in front with two wheel drive towers and 08 and up rear leaves from deaver ( I've had good experience with deavers semi-production springs from CJC off-road 08 up, from wild horses 4x4 built by national spring on an early bronco years ago, and full custom F350 leaves by national spring but that was also at least 15 years ago, all still going strong with hard wheeling and work truck use but not any real high-speed desert type stuff). Large diameter / long travel semi bags for varying load are in the works for current build. Lightest front springs I found are production coils sold by bronco graveyard for the TTB broncos and F150s, coil mounting design may be similar enough to super duties and price cheap enough to just buy and try as mine are not in use yet to give you feedback.

Hope this helps or at least give some more food for thought / research.

 

[madakira]

Here is my Thuren/King 4.0 setup on my 07 5.9. It is Thuren's stage 6 valving, so it is made for high-speed desert stuff. King 4.0's with the extended race resi in the front and King 3.0 Quadruple bypass in the rear. I am running Thuren leaf springs and his Alien long arms in the front. The axle is also using a Thuren truss kit. Carli Ball Joints and Synergy steering setup to keep me going straight.

I love this setup. The Kings eat up all the bumps at 75 mph in the dunes. Desert runs are so fun. I can push this truck over any terrain and it just eats everything up. Of course, if your needs are different, you can go with a softer valving and still get great performance.

 

[mk216v]

Good lawd!

 

[glock7018]

On the topic of softer coil, I am 99% sure the 2017+ trucks still use same coil design. Carli list the same part number for their coils for either an 05 or 2017. That being said what about coils from a new 2020 ford 7.3 Tremor? They have a softer coil in the Tremor? Would take out a lot of the guess work. I would imagine it give you about a 3 inch lift up front.

 

[Buliwyf]

Softer and taller. But OEM's are limited by weak shocks and safety regs. You're better off with 4" coils from BDS, Carli, etc.

Coil swaps are free unless you ding up the coils. But the coils are still cheap. Keep in mind that a 4" spring only nets you 2" more travel. So the travel that a coil over ford setup loses, likely is harmless in the 4" range. I'm sticking to shocks and coils in the OEM spots. I can get good enough there. But many are running 2.5 coil overs, and another 3.0 bypass shock in the OEM location up front. And 3.0 bypass shocks in the rear.

 

[Metcalf]

Here is my Thuren/King 4.0 setup on my 07 5.9. It is Thuren's stage 6 valving, so it is made for high-speed desert stuff. King 4.0's with the extended race resi in the front and King 3.0 Quadruple bypass in the rear. I am running Thuren leaf springs and his Alien long arms in the front. The axle is also using a Thuren truss kit. Carli Ball Joints and Synergy steering setup to keep me going straight.

I love this setup. The Kings eat up all the bumps at 75 mph in the dunes. Desert runs are so fun. I can push this truck over any terrain and it just eats everything up. Of course, if your needs are different, you can go with a softer valving and still get great performance.

Good stuff, an excellent data point from the opposite side of things. I have a few questions.

-Do you hear your bypass shocks?

-Did you try anything in-between getting to this point? One thing I can't find a decent description of is the various differences ( or even rules of thumb ) for when you need more shock diameter. I'm pretty sure I can rule out a 2.0 shock for what I want to do with this truck off-road, it is just too heavy. Some people say you can do a LOT with a proper valved 2.5 shock in a full size. I definitely remember seeing the first KORE and Carli stuff with 2.5s and being amazed. The tipping point in a few areas seems to be between a 2.5 and 3.0 shock as far as packaging, investment, some areas of ride quality, etc. Then throw in the difference between velocity sensitive shocks and position sensitive shocks.....yikes!