Rear Suspension

[lbcadvntr]

More or less. You can't just go by free length. Spring thickness, number of coil wraps, length all affect the spring rate.

I did a paper comparison of a ton of springs here which will give you an idea. To be fair I don't even understand how springs are truly rated because if you compare the King Springs at the top to the Tough Dog ones you'll see they're the same spec yet they have different load ranges.

Rear spring recommendation

forum.ih8mud.com

Is it just me or is it confusing that the 2721 are 0" lift while the 2722 are 0.75" lift given both are the same height. and the 2721s have a progressive spring that's 270#/in & 350#/in while the 2722 are a linear 275#/in. i don't get it...

 

[bloc]

Is it just me or is it confusing that the 2721 are 0" lift while the 2722 are 0.75" lift given both are the same height. and the 2721s have a progressive spring that's 270#/in & 350#/in while the 2722 are a linear 275#/in. i don't get it...

Something odd about "progressive" springs.. when you effectively stack two different rates on top of each other, until one of the coils has bound the whole system ends up at a rate much lower than either of them. In this case the combined rate is about 150#/in until those coils start binding.

Think of it this way.. One 300# spring compresses 1" with 300# on it. Now if you stack another on top, return the weight, each spring will compress 1", so you get 2" total with 300# load, meaning you now have a 150#/in spring.

 

[lbcadvntr]

Something odd about "progressive" springs.. when you effectively stack two different rates on top of each other, until one of the coils has bound the whole system ends up at a rate much lower than either of them. In this case the combined rate is about 150#/in until those coils start binding.

Think of it this way.. One 300# spring compresses 1" with 300# on it. Now if you stack another on top, return the weight, each spring will compress 1", so you get 2" total with 300# load, meaning you now have a 150#/in spring.

Interesting thinking of progressives as to separate springs...
i guess i was thinking of it like my mountain bike fork/shock having linear vs progressive compression. small drops vs big ones / jumps.
anyhow i ordered my springs and went with 2722s b/c i wanted the extra lift. i was told the net lift is actually larger than 0.75". hopefully it is...

 

[lbcadvntr]

@bloc & @linuxgod,

Gents quick update since both of you provide some useful info….

I got the 2722 and BP-51 installed in rear and truck looks great!

I’m bummed I didn’t take measurements pre install but going from 11 yr old stock springs to 2722 the lift in rear was WAY more than what was listed on ARB website (0.75”). I believe in the range of 2”+. I love the stance and amount of rake (pretty much level loaded).

The drive is noticeably better. I haven’t played around with compression and rebound settings beyond initial setting to slightly firmer than recommended from OME.

I think only downside is now I want bigger tires

I’ve been reading on forum and looks like 295/70r18 is largest tire I can fit into apart carrier under truck. Are either of you running oversized tires and did you have to do much if any trimming given 200 with 2”+ of lift? FYI I’m currently running tundra takeoffs with 60mm of offset.

Also have either of you used any sliders to protect spare from damage?

TIA

 

[CT3]

295/70/18 is a do able size, assuming you’re up for some trimming, alignment work etc.

I currently run 275/70/18 without issue and if I were buying new tires today I would probably do 285/70/18 to give myself more clearance on the KDSS and UCA

 

[bloc]

I only went up to 285/70r17 and that fits easily, but now back to stock wheels/tires.

 

[lbcadvntr]

295/70/18 is a do able size, assuming you’re up for some trimming, alignment work etc.

I currently run 275/70/18 without issue and if I were buying new tires today I would probably do 285/70/18 to give myself more clearance on the KDSS and UCA

Hi ct3
That’s interesting going to 285/70/18 only adds another 1/2” or so. Do you have aftermarket UCA? Do you know if KDSS near front driver side would rub with 295/70/18s?
Also, are you on stock wheels or wheels with large + offset? I have tundra takeoffs w +60 offset. I was hoping to just keep those wheels if I went to 295s but would consider aftermarket wheels if that helped eliminate need for trimming or other mods due to larger tires.

I only went up to 285/70r17 and that fits easily, but now back to stock wheels/tires.

did you go back to stock on suspension too?
why did u good back to stock?

 

[CT3]

Hi ct3
That’s interesting going to 285/70/18 only adds another 1/2” or so. Do you have aftermarket UCA? Do you know if KDSS near front driver side would rub with 295/70/18s?
Also, are you on stock wheels or wheels with large + offset? I have tundra takeoffs w +60 offset. I was hoping to just keep those wheels if I went to 295s but would consider aftermarket wheels if that helped eliminate need for trimming or other mods due to larger tires.

did you go back to stock on suspension too?
why did u good back to stock?

I haven’t run 295/70/18 myself, but others have. I personally don’t see a need to go that wide. You will almost certainly rub regardless of offset; if the goal is to have zero rubbing then 275/70/18 is a solid choice and what I am running currently. No rubbing in that size with 1.25in spidertrax spacers and wheels with the same offset as yours.

 

[bloc]

did you go back to stock on suspension too?
why did u good back to stock?

Yes, Low-mile take-off springs, shocks, and UCA's from someone's 2021 build, plus the 10mm OE spacer up front. Stock-sized P-metric Michelin Defender LTX.

It just made more sense given how I use my rig.. lots of road miles to get to the trails, and when I am there I'm too far from home to push really hard anyway. A stock cruiser is probably more capable than I am, so in a way now there are less compromises and it's on me to best use the vehicle instead of slapping band-aids all over it to mask my lack of skill.

 

[lbcadvntr]

Yes, Low-mile take-off springs, shocks, and UCA's from someone's 2021 build, plus the 10mm OE spacer up front. Stock-sized P-metric Michelin Defender LTX.

It just made more sense given how I use my rig.. lots of road miles to get to the trails, and when I am there I'm too far from home to push really hard anyway. A stock cruiser is probably more capable than I am, so in a way now there are less compromises and it's on me to best use the vehicle instead of slapping band-aids all over it to mask my lack of skill.

totally get it. we used to own a wrangler rubicon and initially we did a decent amount of off roading after the first year the tax of getting to trailheads made offroading more challenging and limited it to when we were on vacation in the southwest (AZ or UT).
I don't imagine we'll push our 200 as hard as we did our wrangler but i'm sure we'll have some fun on trips.
for us it's personal preference. i do like the way the 200 looks with a lift and slightly bigger tires.
first thing the mrs.'s asked when i purchased our 200 was "can we put 35s on it"? LOL

 

[lbcadvntr]

I haven’t run 295/70/18 myself, but others have. I personally don’t see a need to go that wide. You will almost certainly rub regardless of offset; if the goal is to have zero rubbing then 275/70/18 is a solid choice and what I am running currently. No rubbing in that size with 1.25in spidertrax spacers and wheels with the same offset as yours.

I agree. I don't really have a need to go wider than 285, but was trying to get to a solid 34" tire next set.
285/70/18 comes out to 33.71"
295/70/18 comes out to 34.26" which would look really nice with the lift provided by BP-51 suspension upgrade (that's all personal preference ).

 

[wiseinvestor]

I put 2722 on my truck for about 2 weeks. Then went up to 2723. You could have my 2722 but I'm not sure what shipping would be.

 

[lbcadvntr]

I put 2722 on my truck for about 2 weeks. Then went up to 2723. You could have my 2722 but I'm not sure what shipping would be.

hey man, appreciate the offer. awfully kind of you.
I already installed the 2722s on my truck a few weeks ago.
did you add aftermarket bumper or extra weight to the rear? is that why you went 2723?
did you happen to measure before and after the 2722 and 2723s? curious how much lift you measured. i think i got 2"+ but didn't measure so i'm going by how different tailgate feels now vs before and the visual gap on rear wheel well .

 

[wiseinvestor]

Yes I have a rear bumper and drawers and that was the reason for the 2723.
With no bumper I went from oem to 2720s.
Then with the bumper on 2722. Then up to 2723.
I'm at about 2.5 over stock.

 

[lbcadvntr]

Yes I have a rear bumper and drawers and that was the reason for the 2723.
With no bumper I went from oem to 2720s.
Then with the bumper on 2722. Then up to 2723.
I'm at about 2.5 over stock.

Nice! i think that is where i ended up. roughly 2.5 over 11 yr old stock springs

 

[lbcadvntr]

Yes I have a rear bumper and drawers and that was the reason for the 2723.
With no bumper I went from oem to 2720s.
Then with the bumper on 2722. Then up to 2723.
I'm at about 2.5 over stock.

Btw i took a quick look at your build page. NICE work! Rig looks awesome! I'll probably be reaching out again with some questions when i have time to look thru it slowly.

 

[TeCKis300]

Something odd about "progressive" springs.. when you effectively stack two different rates on top of each other, until one of the coils has bound the whole system ends up at a rate much lower than either of them. In this case the combined rate is about 150#/in until those coils start binding.

Think of it this way.. One 300# spring compresses 1" with 300# on it. Now if you stack another on top, return the weight, each spring will compress 1", so you get 2" total with 300# load, meaning you now have a 150#/in spring.

Progressives would seem to be a natural choice when concerned with simple things like load handing and ride height. One of the reasons they aren't used in OEM vehicles is they are tricky to tune for. Shocks in particular as damping should be matched to spring rates and progressives change in rate to your point. Then things like ride frequency between front and rear axles. It all gets complicated real quick and OEMs are accountable for a level of refinement that most enthusiasts might trade off.

 

[linuxgod]

@bloc & @linuxgod,

Gents quick update since both of you provide some useful info….

I got the 2722 and BP-51 installed in rear and truck looks great!

I’m bummed I didn’t take measurements pre install but going from 11 yr old stock springs to 2722 the lift in rear was WAY more than what was listed on ARB website (0.75”). I believe in the range of 2”+. I love the stance and amount of rake (pretty much level loaded).

The drive is noticeably better. I haven’t played around with compression and rebound settings beyond initial setting to slightly firmer than recommended from OME.

I think only downside is now I want bigger tires

I’ve been reading on forum and looks like 295/70r18 is largest tire I can fit into apart carrier under truck. Are either of you running oversized tires and did you have to do much if any trimming given 200 with 2”+ of lift? FYI I’m currently running tundra takeoffs with 60mm of offset.

Also have either of you used any sliders to protect spare from damage?

TIA

33.8” will fit under there. That’s about it.

If the tire is inflated it’ll be fine. I’ve slide down mine on Fins and Things when it was still under the truck. I suppose you could bolt a steel plate to it but I don’t think it’s required

 

[lbcadvntr]

33.8” will fit under there. That’s about it.

If the tire is inflated it’ll be fine. I’ve slide down mine on Fins and Things when it was still under the truck. I suppose you could bolt a steel plate to it but I don’t think it’s required

Oh wow. I've been reading on this forum that a folks have fit ~34.3" (295/70/18) under there.
How was Fins and Things with LC? I've done it with my jeep before. do you have skids? did you feel you needed them?
do you have lockers on your rig?

 

[linuxgod]

Oh wow. I've been reading on this forum that a folks have fit ~34.3" (295/70/18) under there.
How was Fins and Things with LC? I've done it with my jeep before. do you have skids? did you feel you needed them?
do you have lockers on your rig?

I had lockers but no skids when I did it. Didn’t really need them tho. The trail was fine with the LC, just know you’ll drag the rear bumper a bit.

I fit a 33.8” spare and it was tight. Maybe 34.3 will fit.