Factory Spring Part Numbers & Associated Lift

[Gordinho80]

Over 3 weeks later... 34" mean to fender line...

I'm over 1.5" taller with the 88s and no shim... imagine I had decided to put in the shim. I've got a bit of negative rake now as is. I might have to look into the SkyJacker CR25 springs for the rear soon.

[Philberto]

Apparently I have 82s... I plan on ordering 86s pretty soon to replace the sagging fronts, and I'll be letting you all know how that turns out.

[djthumper]

I have an 82 and an 83. So if I go to 87 springs I will get about a 1" lift. And changing out the rear springs with Z71 springs that should give me 1.5" in the rear.

[dlcsjoyce]

Well, thanks to rgraboske, I now know what my stock front springs were.... I think I'm the only TB on here that had an 81 spring!!! 6CC is my driver side, which is an 83, and 7CB is pass side, which is an 81!!! WOW. No wonder I had to trim so much plastic from my fender liner to clear the 32s. Now that I think about it, I noticed more rubbing on compression on the pass side then I did on the driver side.

Well.... am I glad I updated the springs now. I had an 81!!!!

I would like to think the both of you for this find. I have the same RPO codes 6cc and 7cb on my 2004 and was curious as to what the spring number was, knowing this I'inm thinkg about getting a set of 87 springs in the near future.

[rgraboske]

I'm working to put a complete list of RPO codes together. I've found over 60 RPO codes for each part number so far

[Trail X]

I'm working to put a complete list of RPO codes together. I've found over 60 RPO codes for each part number so far

Are they all for TBs? I assume some are for the SSR?

[rgraboske]

I'm working to put a complete list of RPO codes together. I've found over 60 RPO codes for each part number so far

Are they all for TBs? I assume some are for the SSR?

You assume correctly. They have SSR RPO codes for most of the part numbers. I'll have to look at some SSRs to see what springs they seem to have in real life.

[Trail X]

Finally got around to this.

Old and new, no visible difference between heights, but the 87 spring is a much thicker wire.


So thick that the safety latches on the spring compressor didn't fit over it (it did for the 83s).


Did this along with extra top washers and flipping the UCAs.


End result is 38" ground to fender (with my heavy bumper), no harsh topping out noted when going over speed bumps. However it looks like I now need helper bags in the rear.

[fishsticks]

Well done, keep an eye on those CV joints now... we stretch them a bit father than they're probably happy with.

[dirty anton]

looks good james! i don't have the extra washers but when i flipped the uca's i swear the truck
drove better,maybe it's in my mind cause the bj's have a better angle now. fish.
almost afraid to get it aligned now cause it's driving spot on

[Trail X]

Well done, keep an eye on those CV joints now... we stretch them a bit father than they're probably happy with.

I rotated the hubs while trying to figure out how many washers to add. It seemed fine even beyond full extension. How many washers did you add? I was only able to add about 5. The equivalent to maybe 0.4".

almost afraid to get it aligned now cause it's driving spot on

I'm going to in a few weeks, to let everything settle a bit. I've got visible positive camber.

[fishsticks]

I rotated the hubs while trying to figure out how many washers to add. It seemed fine even beyond full extension. How many washers did you add? I was only able to add about 5. The equivalent to maybe 0.4".

IIRC, I was able to get around 11/16" on there. My OEM CV axles had a very slight amount of resistance at the tripods when fully extended.

[Trail X]

How many washers did you add? I was only able to add about 5. The equivalent to maybe 0.4".

IIRC, I was able to get around 11/16" on there. My OEM CV axles had a very slight amount of resistance at the tripods when fully extended.

The difference must be the bushing thickness between the Rough Country and the BDS. Based on your photos here viewtopic.php?p=19605#p19605 The BDS bushings look much thicker, which takes away from the available space to put washers.

Looks like your shock still has 5mm of shock-rod sticking out the top... mine has less than 1 mm. I only had a 12mm of shock thread protruding before the washers were added.

Given all of the differences though - I'd bet our shocks are probably extended similar lengths now when in full droop.

[Flying Monkey]

So am I understanding this thread right, I have 2 different springs in the front?

6CC - COMP FRT LH COMPUTER SEL SUSP
7CB - FRONT SPRING


CC=81
CB=83



Which also tells me when doing my lift Im going to want to step up to a 85 or 86 set of springs so as not to slam a tire into the wheel well. I dont have an after market bumper but plan on putting 1 on, but wont be for awhile Im sure. So best to not to get the stiff spring to support a bumper I dont have yet and dont know when ill have it.

switching springs would add the difference of:

L-85=.86", 86=1.02", 87=1.14"
R-85=.45", 86=.63", 87=.77"

What i wouldnt give for leaf springs back

If Im wrong here let me know....rip me, haze me or whatever lol..Just throw in the part im wrong so I know lol

[Trail X]

You forgot to multiply by the lever arm factor. The numbers you reported were spring lift.

[bgwolfpack]

James,

Do new rubber bushings come with the BDS kit because as far as I remember the RC kit does not and only stock or replacement shock bushings are used.
Is the plate thickness that much heavier on the BDS too? This could be part of the difference also.

Chris,

You very well may have two different numbered springs at each corner of the front end and if you plan to (or already have) a lot more weight in the front then 86 or 87 will help keep the front end up. They do not however make a change in the overall travel of the wheel and tire clearance to the fender well.

[Flying Monkey]

Ok from a 81 left and 83 right

Spring lift difference of:

L-85=.86", 86=1.02", 87=1.14"
R-85=.45", 86=.63", 87=.77"


Wheel lift difference of:

L-85=1.27", 86=1.5", 87=1.68"
R-85=.67", 86=.93", 87=1.13"

Im sorry if this is annoying but Im really confused on spring lift vs wheel lift. I even googled it and cant find answer. I understand the getting stiffer ride from the higher spring rates because there is more resistance. Also the gaining of some height because of same resistance not letting vehicle weight tax the heavier springs as much as the lighter springs, also less roll more tilt factor. Being that Im going to a larger tire Im understanding I want a stiffer spring then what mine has too keep it out of the wheel well on bumps/terrain. but bgwolfpacks comment confused me cause what im lookign at is bigger tire=less clearence to wheel well, in turn allowing it to hit when suspension compressed due to weak spring, so need stiffer spring to not let that happen.


Ive never dealt with this before. Always just ordered X" lift and put in new front leafs and blocks in rear. I just want to do the lift right the first time

[Trail X]

Randy, BDS does come with new top poly shock bushings.

If I recall, the BDS mounting plate is a good bit thicker than the stock plate, 1/4" or so. So you're right, it could be an added factor.

Im sorry if this is annoying but Im really confused on spring lift vs wheel lift. I even googled it and cant find answer.

It's an IFS thing. The strut is mounted inboard of the lower ball joint, so there is a lever arm effect between how much you lift the strut, versus how much actual lift you get (dubbed here as wheel lift).

[Flying Monkey]

So basically putting markmc's 2.5" lift and swapping the front springs to 86 or 87's will level the stance. But adding z71 springs to the rear will raise rear back up higher then front. Which after reading alot of the build threads is the way alot of people go.

[fishsticks]

Randy, BDS does come with new top poly shock bushings.

If I recall, the BDS mounting plate is a good bit thicker than the stock plate, 1/4" or so. So you're right, it could be an added factor.

Im sorry if this is annoying but Im really confused on spring lift vs wheel lift. I even googled it and cant find answer.

It's an IFS thing. The strut is mounted inboard of the lower ball joint, so there is a lever arm effect between how much you lift the strut, versus how much actual lift you get (dubbed here as wheel lift).

The Rough Country uses new bushings and the top plate is 1/4" as well. The biggest difference between the two is the lack of a 3rd bolt hole and non-welded in studs.