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Spring rates...

9K views 15 replies 8 participants last post by  Tollmtn 
#1 ·
I know there was a thread about this a long time ago but I can't find it at the moment... I'm on my phone. Anyways can someone tell me what the stiffest spring would be in the 4"-5" height range? I do alot of towing and the Rustys 2.5" aren't cutting it. So... what is the best spring that won't sag when a heavy load is applied to them? And what will give me that "leaf spring truck like" ride?

And no... I don't want to sell it and get a xj or yj so don't go there lol

I know IRO makes 4.5" HD rear springs I just didn't know how heavy duty they are
 
#2 ·
If I remember correctly, Clayton had the stiffest 4.5" set at around 210lbs. front and rear. IRO HD rears were something like 250lbs.
 
#5 ·
No there not only have about 10-15k on them but I think my girlfriends dad wants them for his 02 wj but not 100% sure
 
#6 ·
Looks like according to that chart I could do some IRO rears and either Clayton or teraflex fronts...
 
#10 ·
wjjeeps has them listed between 845-1085 lb, but this cant be inch/lbs. I think its total weight limit or something. I'm not sure how to convert the two. I was going to do the math but There is so many different standard spring rates for the WJ. I guess you would have to take a coil off and put weight on and see how much it would take to make it compress one inch. And I would guess that the rate is not constant thru the entire range of the coil. Any aftermarket coil is an upgrade and Kolak can get you the right setup. Those Cali girls in Bikini's will be wanting to wheel in no time LOL.
Just go with a good brand and you will be happy. Go with a heavier spring rate if you plan on towing or have added weight. Go with a lighter spring rate if you plan on flexing. Either way it's a win/win situation.:)
 
#11 ·
I saw the wjjeeps thing, didn't make a bit of sense. I can't come up with any way those numbers could be compared to the 175-250 pounds per inch rates of aftermarket coils. It'd just be nice to know if those 240 lb/inch BDS coils are replacing 125 pound stock coils or 200 pound stock coils..

If anyone has a stock coil laying around its not too hard to get a ballpark measurement of the rate.. a bathroom scale, a tape measure and a 2x4 can get close.
 
#12 ·
Stock Spring Rate

i had e-mailed rocky-road a while back on some ome spring rates and they gave me a stock comparison. I was told that stock was 170# front and 160# rear. Take this how you will coming from rocky-road, all i have heard is bad about them.

On another note, this whole spring rate thing is driving me crazy, currently shopping for a lift myself.
 
#13 ·
also gonna bump this along with the other thread, just in case, has some good knowledge in it
 
#14 ·
BDS is the highest spring rate front and rear at 240 for both. The front are 4" and rear are 3.5". I believe tollmtn stated in a thread a while back, when we were discussing something similar to your situation, that the free hight and spring rate of the IRO HD 4.5" spings would match well with the 4" front BDS springs. I would say your best bet is BDS 4" front at 240 and the IRO HD 4.5" rears that are either 240 or 250. I have the 4 inch BDS springs (3.5 rear), and they actually ride really well. But there is a slight sag when loaded down.

Forgot to mention Zone (Both Zone and BDS are owned by Sport Truck USA) 4" front and 3.5 rear are also 240 each, it is the value brand lesser than BDS

Just some food for thought

:cheers2:
 
#15 ·
Thanks for the input .. I've actually already bought a set of 4.5" Clayton Springs for mine but just figured I'd bump this for the good info incase anyone else was trying to find it
 
#16 ·
Good choice of springs.

To add to the info here.....I noticed an unanswered question about the lbs. numbers ranging from 845-1085 lbs. on wjjeeps web site. That number is the load in lbs. that it would take to compress that spring from it's free height to a certain height in inches. For example a 1,085 lb. load on a spring with a free height of 15" compresses that spring to a certain height, for example 10". As you can see you could use that information to calculate the spring rate of that spring. The problem is the information on wjjeeps is useless for calculating spring rate because we do not know the springs free heights or what height with load they used.

What we do know....Just going by P/Ns Mopar installed 7 different standard front springs and two different UC front springs. In the rear they installed 4 different standard springs, 2 different standard height tow package springs and 2 different UC springs.

I have read some of the front spring rates were as low as 160 lbs.in. The only OEM WJ springs that I have had in my hands is the standard height tow package springs that I removed from my 2004 Overland. I calculated the rates for them as 180 lbs/.in. front and 200 + lbs.in. for the rear springs.

To clarify the rate of IRO's rear HD springs they are 4.5" 240 lb/in springs. As captain mentioned BDS spring rates are 240 lb F and R. The 4" lift rear springs are actually 3.5" springs, the reason for this is to correct for rake. Some people do not mind the rear to front rake and some myself included actually prefer the rake so a good combination BDS 4" front and IRO 4.5" HD springs in the rear.

There is a thread specifically for spring rates and associated information like free heights. The most accurate way to know what to expect lift wise out of a set of springs from different manufactures is to compare the rates and free heights, some free heights info is in post 10 http://www.jeepforum.com/forum/f310/spring-rate-information-contribution-thread-3246721/
 
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