Lets talk about springs...

Mike_H

autos are better - WRWD508
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Grand Rapids, MI, United States
I'm getting ready to pull the trigger on a "lift kit" spec'ed by me. Still mulling around spring choices. I thought I was going with H&R...but I KNOW I'll want 33's, eventually. I get tire envy. The 32" Mud Terrains I'm running look good, but....well, you know. 1" lift ain't gonna cut it. Anyway, springs.

Looking at a 2" lift spring. I already have a set of 3/4" spring spacers to make minor adjustments (level after bumper and winch) if necessary. Terraflex, BDS, ARB / OME, and Pro-Comp all make a spring for a 2" lift. In my mind, the quality would be
  1. ARB / OME
  2. Teraflex and BDS (tied)
  3. Pro-Comp
However...cost wise, the order is different:
  1. Teraflex - just over 200 a pair
  2. OME at 167 a pair
  3. Pro-Comp at about 160 a pair
  4. BDS for about 110 a pair.
Since OME and Pro-Comp are so close in price and I've heard so much positive about OME, I've Crossed Pro-Comp off the list. Teraflex seems to me more like a mass market company (similar to Rough Country) so I'm thinking their quality is less than OME. I could be very wrong...I just don't know.

The Discussion I'd like to have is:

  • Is Teraflex better than OME as far as their springs? My understanding is that OME really shines because of the shocks, not the springs.
  • Is BDS of the same quality?
There are definitely three price tiers here. Teraflex will be 400, OME 330, and BDS just over 220. I'm a "Value Hunter." I'm not cheap in that I will spend to get a high quality item...but I also don't spend needlessly. There is a law of diminishing returns and I like to ride the edge of that. In other words, I like to spend as little as possible to get the best quality I can.

Just to help fill in the gaps, my Jeeping is a little bit of everything. I commute when its nice (75-80 mph), run a lot of forest roads, I get into the sand, some mud, and even some rocks. I don't plan on anything bigger than 33's and I do plan on adding a Body and Motor Mount lift to get me the clearance I need for 33's.
 
My experience is limited to OME springs, but you'll want to look at spring rates. Why does OME offer 2 spring rates for the same lift height spring? I can tell you this, I have literally 1/4" of spring sag after 10 years and 115k miles of not light use with my OME springs. That would be a consideration. BDS offers a "No questions asked" warranty on their springs, so there's that. I wheel similar situations that you do, and don't plan to go bigger than 33's.
 
I found this formula online while reading up about springs...I've taken a class about springs (more than one, really), but have forgotten more than I remember...Anyway, if I could get actual pictures of each of the springs I'm looking at and some measurements, I could calculate the pertinent information myself...of course, I'm not sure what I'd do with it, as I don't know what the design considerations were originally...

http://www.bluecoilspring.com/rate.htm

Believe it or not, I used to make springs...of course, they were tiny little suckers used in valve lash adjusters but still...
 
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Slippery slope. Springs need to keep your jeep at a certain height without it riding like a dump truck. it is my theory that finding a spring with the least in.lbs. of spring rate that maintains the lift height advertised would be my choice.
 
Slippery slope. Springs need to keep your jeep at a certain height without it riding like a dump truck. it is my theory that finding a spring with the least in.lbs. of spring rate that maintains the lift height advertised would be my choice.
All other things being equal, more active coils means a lower rate. Also, smaller diameter wire is a lower rate. Its all a balancing act tho, as the more coils you add, the less travel you get before coil bind. Start pulling coils out, internal stress in the steel increases and it will shorten the life of the spring (whether that shorter life is practical is another question).

I know how to spec a spring for a plastic injection mold and get good life. I don't know a thing about automotive springs.
 
All other things being equal, more active coils means a lower rate. Also, smaller diameter wire is a lower rate. Its all a balancing act tho, as the more coils you add, the less travel you get before coil bind. Start pulling coils out, internal stress in the steel increases and it will shorten the life of the spring (whether that shorter life is practical is another question).

I know how to spec a spring for a plastic injection mold and get good life. I don't know a thing about automotive springs.

I think you're on the right track. I went with OME HD springs (933/942's) thinking I was going to put a lot of weight in the rear. I ended up not.
 
Found this over on Pirate...take it with a grain of salt...but interesting nonetheless.

spring rates.jpg
 
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I think you're on the right track. I went with OME HD springs (933/942's) thinking I was going to put a lot of weight in the rear. I ended up not.
My original thought is OME HD springs in front and MD springs in the rear (933/941). I don't carry a ton of gear, I have a truck for pulling trailers, etc. so I don't need the HD rear springs (I think). I do, however, plan on a pretty good bumper and winch up front.

I'm taking a page out of @StG58 's book with this thread, just putting something crazy out for discussion. Hopefully, @Jerry Bransford and/or @mrblaine will take an interest and throw some real knowledge at it.

Oh, I'm also just kinda being a little squeaky, trying to save 100 bucks! :)
 
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I'm getting ready to pull the trigger on a "lift kit" spec'ed by me. Still mulling around spring choices. I thought I was going with H&R...but I KNOW I'll want 33's, eventually. I get tire envy. The 32" Mud Terrains I'm running look good, but....well, you know. 1" lift ain't gonna cut it. Anyway, springs.

Looking at a 2" lift spring. I already have a set of 3/4" spring spacers to make minor adjustments (level after bumper and winch) if necessary. Terraflex, BDS, ARB / OME, and Pro-Comp all make a spring for a 2" lift. In my mind, the quality would be
  1. ARB / OME
  2. Teraflex and BDS (tied)
  3. Pro-Comp
However...cost wise, the order is different:
  1. Teraflex - just over 200 a pair
  2. OME at 167 a pair
  3. Pro-Comp at about 160 a pair
  4. BDS for about 110 a pair.
Since OME and Pro-Comp are so close in price and I've heard so much positive about OME, I've Crossed Pro-Comp off the list. Teraflex seems to me more like a mass market company (similar to Rough Country) so I'm thinking their quality is less than OME. I could be very wrong...I just don't know.

The Discussion I'd like to have is:

  • Is Teraflex better than OME as far as their springs? My understanding is that OME really shines because of the shocks, not the springs.
  • Is BDS of the same quality?
There are definitely three price tiers here. Teraflex will be 400, OME 330, and BDS just over 220. I'm a "Value Hunter." I'm not cheap in that I will spend to get a high quality item...but I also don't spend needlessly. There is a law of diminishing returns and I like to ride the edge of that. In other words, I like to spend as little as possible to get the best quality I can.

Just to help fill in the gaps, my Jeeping is a little bit of everything. I commute when its nice (75-80 mph), run a lot of forest roads, I get into the sand, some mud, and even some rocks. I don't plan on anything bigger than 33's and I do plan on adding a Body and Motor Mount lift to get me the clearance I need for 33's.

I just ordered the OME (HD) springs, for the price difference and the reason being that they aren’t too expensive like the Teraflex imo. They may be great and I actually live about 3 miles from a Teraflex warehouse that I could will call anything from their catalog and pick it up same day with no shipping. Having said that, there’s actual proof that they (OME) will last 10+ years with a 1/4 inch of sag after 100,000 plus miles is what sold me. The others may be good springs and some members on here will tell you that it’s more about the shocks that you run anyways, but.... I’ve read so much on here about OME and bobthetj03’s experience that to me for $25 more per spring is better than “finding out the hard way” and if you decide to change them out later which does happen that you could resale them based on reputation.
Just my thought process.


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I bought the ome hd (933/942) for my lj based solely on info I read on this forum.
FedEx delivered them yesterday. I purchased mine from morris4x4 . They were 167 a pair and there was a promo code (DEC30) for $30 off anything over $300 and free shipping. While i cant offer an opinion on quality yet, sometimes a deal can help with a decision.
Mike
 
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All other things being equal, more active coils means a lower rate. Also, smaller diameter wire is a lower rate. Its all a balancing act tho, as the more coils you add, the less travel you get before coil bind. Start pulling coils out, internal stress in the steel increases and it will shorten the life of the spring (whether that shorter life is practical is another question).

I know how to spec a spring for a plastic injection mold and get good life. I don't know a thing about automotive springs.
Since you used to design springs, the rear OEM springs on a TJ should be interesting for you. They are a true progressive spring and in the world of springs, exorbitantly expensive to make. They start with a specific length of spring wire and then it is tapered from both ends to the middle. I don't know if they are ground or heated and drawn to reduce the diameter from the middle, but only a few coils in the middle of the spring are the larger diameter and they reduce to the smallest at both ends.
 
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Since you used to design springs, the rear OEM springs on a TJ should be interesting for you. They are a true progressive spring and in the world of springs, exorbitantly expensive to make. They start with a specific length of spring wire and then it is tapered from both ends to the middle. I don't know if they are ground or heated and drawn to reduce the diameter from the middle, but only a few coils in the middle of the spring are the larger diameter and they reduce to the smallest at both ends.

I didn't design...just had to set up a coiler to make the spring that some egghead in GM corporate designed for me. Knowing roughly how springs are made though...The wire probably comes in on a big coil, and they cold draw it to thin the diameter. There are four main parts on a spring coiler...the Feed rolls, The arbor (sets the pitch), The anvil (sets diameter) and the cutter. Most of them are CNC controlled. I can see a coiler that has two sets of feed rolls, one to draw the wire down in size, and one to feed. They would both have to be on linear actuators, so that they would adjust to the variable diameter. Its an interesting though exercise to try and think through how I would make one. Set-up sounds like a nightmare too.

Picking a spring for an injection mold is pretty straightforward. You basically calculate the stroke you need, and the diameter of your return pins. Once you have that, you pick a spring from a catalog that will compress less than 30% of its free length (for decent life), and machine a pocket that will hold it. It gets a little more tricky if you don't have enough steel depth to hold the free length and still maintain the 30% compression factor.

When thinking about a vehicle, the load and cycling is variable instead of fixed, your "pocket" is pretty well constrained, and design specifications are pretty much non-existent. So...its a guess based on forum reviews and pocketbook.
 
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My original thought is OME HD springs in front and MD springs in the rear (933/941). I don't carry a ton of gear, I have a truck for pulling trailers, etc. so I don't need the HD rear springs (I think). I do, however, plan on a pretty good bumper and winch up front.

I'm taking a page out of @StG58 's book with this thread, just putting something crazy out for discussion. Hopefully, @Jerry Bransford and/or @mrblaine will take an interest and throw some real knowledge at it.

Oh, I'm also just kinda being a little squeaky, trying to save 100 bucks! :)

I think the 933/941 would be a good combination for your rig. I wish I would have went that route since 90% of my driving is with no gear and a light rear end. The 942's shine if you're loaded down with 300lbs. of gear and dogs in the back, and a small camp trailer. The rest of the time, it's a bit rougher riding.
 
I was in the same situation last month and narrowed by decision down to OME and BDS. I decided to go with BDS as their Tech Support guys were fantastic and really talked me through the decision making process. Plus the warranty is the best! I could not be happier with the ride quality and really looking forward to hitting some trails.
 
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I was in the same situation last month and narrowed by decision down to OME and BDS. I decided to go with BDS as their Tech Support guys were fantastic and really talked me through the decision making process. Plus the warranty is the best! I could not be happier with the ride quality and really looking forward to hitting some trails.
Did you buy them from BDS directly? I ask because I tried to look at the BDS website, and it sucks. I could not find anything successfully there.

Any before and after pics?
 
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Did you buy them from BDS directly? I ask because I tried to look at the BDS website, and it sucks. I could not find anything successfully there.

Any before and after pics?

I bought them from offroadwarehouse.com If you are a new user, they offer 5% off plus free shipping.

Before:
IMG_3254.PNG

After:
With 31" BFG's. Measurements after were almost 3" higher but I think they may have to settle.
IMG_3255.PNG
 
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Here's a thought on this topic...of those 2" lift springs that fall into the category of possibly good springs that are part of a not-so-great kit, usually due to shocks that suck, how do these compare, just the coil springs:

BDS
Rough Country
ProComp
Rubicon Express

Or any others not listed...