Bumpstop question

tommudd · **Posted:** Thu Jan 15, 2009 11:08 am

You know people ask for some information ,

they can choose to use the information or not. :shock:

I do not sell any type of lift products so I make no money when your springs go bad and you buy another set.

So to those who don't want to use the information after they ask, good luck, but like I have stated numerous times, the number one way to kill your springs is from stacking, that even comes from ARB/OME.

Sometimes the best learned lessons is from experience, and hopefully some day after you replace your sagging springs you will have learned a thing or two.

If you really want to get into who is right, wrong or otherwise...the only way OME will warranty springs is if they have been used with OME shocks and NO OTHER items used with the springs such as the way the Frankenlift is designed.

Thank you and have a wonderful day :wink:

KJ04 · **Posted:** Thu Jan 15, 2009 12:01 pm

This past Spring I installed the Teraflex extended bump stops and OME CRD 790's on the front of my "3.7 Heavy Gasser" (ARB, winch, full armor, All J's rock rails and 1/4" tranny skid).
My buddy commented, that the upper A-arm would not even contact the bump stops with the 500 lb. coil rate of the springs.... However, my first off-road trip revealed grease spots from the JBA A-arms on the bump stops. I then had to drill a hole in the stop for the grease zerk.

So, when a company reccomends a 400 lb. rate coil for a ARB bumper and winch that weighs in at 180 lbs. + armor, and then reccomends a 500 lb. coil rate for a CRD engine that weighs 200 lbs. more than a gasser, it makes you wonder.

"I'm guessing", the reason AJ's says you don't need front bumps with the Frankinlift is, based on the stock weight of a KJ, in which case it would be hard to over compress anything with 400 lb. rate coils and a their added Daystar spacer which would boost the coil rate factor even more.

Personally, I would add extended bump stops any time you lift it period.

sidewayskj · **Posted:** Thu Jan 15, 2009 12:16 pm

Yea I don't have an ome lift but a bds spring lift(front spring weight 400lbs), and I put the extended bump stops on the front and once my arms have hit the stop so I would say running them in a good insurance because just changing out your front struts alone make it well worth the money on stops. Just my 2 cents

BjBnet · **Posted:** Thu Jan 15, 2009 3:49 pm

tommudd wrote:

If you really want to get into who is right, wrong or otherwise...the only way OME will warranty springs is if they have been used with OME shocks and NO OTHER items used with the springs such as the way the Frankenlift is designed.

Thank you and have a wonderful day :wink:

hmmm, interesting. BTW Tom, wasn't saying you were wrong, just wondered why All Js said they weren't needed.
Not too many people question your posts here so I'll go with your experience.
Thanks Tom!

dieselenthusiast · **Posted:** Sun Jan 18, 2009 11:35 am

I ordered bump stops through trailquest. I’m pretty impressed with their customer service and all the products that they carry. I will definitely do business with them again.

long_tall_texan · **Posted:** Sun Jan 18, 2009 8:15 pm

Speaking of the extended bumpstops, isn't there a trick to getting those suckers on? Daystar just sent mine to me, I tried for about 15 minutes to get one on today. Used white silicone grease spray, a big sledge, and didn't even get close. there has to be a trick. Somebody help.

snowsport · **Joined:** Tue Oct 18, 2005 11:52 pm **Posts:** 1211

Yeah, I had a red-hot dickens of a time getting my Teraflex bumpstops in, too. Finally wrastled the buggers in there with brute force and stupidity. Not to mention cussing and growling.
Someone else here says they slip in pretty easy if you squirt them with a little dish wash liquid. :evil:

Give that a try and see what's what. :wink:

tommudd · **Posted:** Mon Jan 19, 2009 12:13 pm

Not that hard to get in, put something slippery on the top of it, start the back side in, now get a long bar and wedge into the spring so you can pry up on the bumpstop, this is where a third hand comes in, take a punch or screwdriver and where the ridges are push in on those first on each side then the middle, while prying up.
I did mine myself but when we did the ones on Chris' it was easier with three or four hands, :wink:

make sure they are nice and warm as well. After you are done smack them with a BFH a couple of times to make sure thay are seated good

OH if you have JBA upper arms make sure you cut a notch for the grease zerk

long_tall_texan · **Posted:** Mon Jan 19, 2009 1:05 pm

I knew you would come thru for me here Tom. I just tried holding it and banging with a Big Hammer. That doesn't work. Thanks!

tommudd · **Posted:** Mon Jan 19, 2009 1:14 pm

long_tall_texan wrote:

I knew you would come thru for me here Tom. I just tried holding it and banging with a Big Hammer. That doesn't work. Thanks!

steady pressure seems to work best, you'll get them :wink:

long_tall_texan · **Posted:** Sun Feb 01, 2009 1:11 am

Just to follow up on this... How to get the front bumpstops installed - the easy way.

I finally got around to putting these on today. I followed jeepkj02's advice and used the shovel method. It was surprisingly easy when you have the giant cheater-bar of the entire shovel handle.

Length of the Daystar Front Bumpstops, in case anyone wanted to know. I think the question had come up before. Now we all know.

Then here is how you press them in. Just be careful when putting the end of the shovel in the springs not to cut or pull your shock boot loose.

All done!

long_tall_texan · **Posted:** Mon Feb 09, 2009 11:25 pm

Well, Someone said that if you want the truth, get it straight from the source. Sooooo. I decided to ask ARB aka OME their thought about the usage of extended bumpstops. I think we can all agree that they would be considered the experts in this field. Right?

Here is my original message to them...
------------------------
I have a technical question regarding the usage of the OME 927 springs to lift the Jeep Liberty. There is a large community of KJ owners at lostkjs.com which frequently have questions regarding lifting the KJ. It is generally accepted that the OME springs are hands-down the best, and most reliable long-term lift option for our KJs. However, there is always a debate around whether or not extended bumpstops are needed, required, or just a good safety net. For simplicity sake, I am limiting this to front suspension of the KJ.

Using the OME lift, OME 927 springs and NS131 shocks are used. No bumpstops are provided with this lift. Hear-say says that the reason no bumpstops are needed is because the OME front shocks have a bumpstop built into the shock internally. Is this true?

Another popular combination is the OME 927 springs and Rancho RSX 17505 shocks. In this case it is generally said that extended bumpstops be used to keep from over compressing or stacking the OME springs.

So the basic question I am asking is:

1. Does over compressing or stacking the OME springs weaken them, cause them to sag over time, lead to early failure, or cause added fatigue on the springs? (being an engineer myself, I know this answer, but would like to relay it directly from the manufacturer to others in this community that do not understand spring dynamics)

2. What is the designed minimum compressed length of the OME 927 springs? By this I mean the maximum compression not to exceed on a regular basis without causing permanant deformation of the springs.

Here is one of the many discussions regarding this bumpstop dilemma: http://www.lostjeeps.com/forum/phpBB3/vie ... 789#410789 Although the picture shown here has a spacer lift, I would assume that the same concept applies when adding longer springs such as the OME 927's.

Thanks in advance for any light you can shed on this subject.

----------------------------------------------
I quickly got a response from Marc. The same guy Tom had mentioned earlier. He is a tech specialist for Arb. But he didn't know the exact answer to the depth of design that I wanted, so he passed it on to engineering. Here is their reply - directly from the senior design engineer of OME spings.
---------------------------------

By adding a spring spacer without a bump stop spacer, you are creating a situation where you may over compress the spring. In the worst case, the spring will go solid before the bump stop has been contacted. The factory spring has been designed to work from its free height through ride height to minimum compressed height so that stresses do not exceed the limit of the spring material.

By adding the spring spacer without a bump stop spacer, you are increasing the deflection of the spring before the suspension bottoms out on the bump stop. As you increase spring deflection, you increase stress. You may increase stress to the point where the stress is higher than the limit for that spring material. In this situation, the spring will sag, lose height, or fail.

When designing the OME spring, we calculate the maximum stress that spring design will encounter when it is compressed past maximum bump stop compression. We use a high stress material to produce OME springs. This means the material can withstand very high stresses before it gets to the point where it will sag and lose height.

The amount of stress the spring experiences can be altered by changing wire diameter, spring body diameter and number of coils. Of course altering these variables also changes the spring rate, free height, and solid height. The spring rate needs to be correct to carry the load. The free height needs to be right to give the correct ride height and long enough so that the spring does not become untrapped and fall out at the full extension of the strut or shock. The solid height is also important. If the spring has too many coils or wire diameter is too thick, the spring will go solid before contacting the bump stop.

By adding a spring spacer to the factory spring and a bump stop spacer of the same thickness, the factory spring will not experience any greater stress than with the factory setup (so spring spacers or bump stop spacers). In this situation you have higher ride height but the same up travel or compression as the factory setup. With the OME spring you have the benefit of lift and extra travel as we do not require fitting a bump stop spacer to prevent the spring being overstressed.

Marc your customers should be confident that the maximum stress the spring will encounter when correctly installed for its intended application will be within the maximum stresses the material can handle.

Senior Design Engineer
Old Man Emu
ARB Corporation Limited

------------------------------------------------

Now, all of that being said, I guess if you use OME springs alone to lift your KJ, then you don't need extended bumpstops. They say that they have designed the OME springs to allow for increased travel. No need to limit it by adding extended bumpstops.

But... From what they said, if you are installing a spacer lift (and this would include the OMEs when used in a Frankie) extended bumpstops are needed to prevent over compressing the springs.

There you have it. Let the horse beating begin....

tjkj2002 · **Posted:** Mon Feb 09, 2009 11:30 pm

long_tall_texan wrote:

Well, Someone said that if you want the truth, get it straight from the source. Sooooo. I decided to ask ARB aka OME their thought about the usage of extended bumpstops. I think we can all agree that they would be considered the experts in this field. Right?

Here is my original message to them...
------------------------
I have a technical question regarding the usage of the OME 927 springs to lift the Jeep Liberty. There is a large community of KJ owners at lostkjs.com which frequently have questions regarding lifting the KJ. It is generally accepted that the OME springs are hands-down the best, and most reliable long-term lift option for our KJs. However, there is always a debate around whether or not extended bumpstops are needed, required, or just a good safety net. For simplicity sake, I am limiting this to front suspension of the KJ.

Using the OME lift, OME 927 springs and NS131 shocks are used. No bumpstops are provided with this lift. Hear-say says that the reason no bumpstops are needed is because the OME front shocks have a bumpstop built into the shock internally. Is this true?

Another popular combination is the OME 927 springs and Rancho RSX 17505 shocks. In this case it is generally said that extended bumpstops be used to keep from over compressing or stacking the OME springs.

So the basic question I am asking is:

1. Does over compressing or stacking the OME springs weaken them, cause them to sag over time, lead to early failure, or cause added fatigue on the springs? (being an engineer myself, I know this answer, but would like to relay it directly from the manufacturer to others in this community that do not understand spring dynamics)

2. What is the designed minimum compressed length of the OME 927 springs? By this I mean the maximum compression not to exceed on a regular basis without causing permanant deformation of the springs.

Here is one of the many discussions regarding this bumpstop dilemma: http://www.lostjeeps.com/forum/phpBB3/vie ... 789#410789 Although the picture shown here has a spacer lift, I would assume that the same concept applies when adding longer springs such as the OME 927's.

Thanks in advance for any light you can shed on this subject.

----------------------------------------------
I quickly got a response from Marc. The same guy Tom had mentioned earlier. He is a tech specialist for Arb. But he didn't know the exact answer to the depth of design that I wanted, so he passed it on to engineering. Here is their reply - directly from the senior design engineer of OME spings.
---------------------------------

By adding a spring spacer without a bump stop spacer, you are creating a situation where you may over compress the spring. In the worst case, the spring will go solid before the bump stop has been contacted. The factory spring has been designed to work from its free height through ride height to minimum compressed height so that stresses do not exceed the limit of the spring material.

By adding the spring spacer without a bump stop spacer, you are increasing the deflection of the spring before the suspension bottoms out on the bump stop. As you increase spring deflection, you increase stress. You may increase stress to the point where the stress is higher than the limit for that spring material. In this situation, the spring will sag, lose height, or fail.

When designing the OME spring, we calculate the maximum stress that spring design will encounter when it is compressed past maximum bump stop compression. We use a high stress material to produce OME springs. This means the material can withstand very high stresses before it gets to the point where it will sag and lose height.

The amount of stress the spring experiences can be altered by changing wire diameter, spring body diameter and number of coils. Of course altering these variables also changes the spring rate, free height, and solid height. The spring rate needs to be correct to carry the load. The free height needs to be right to give the correct ride height and long enough so that the spring does not become untrapped and fall out at the full extension of the strut or shock. The solid height is also important. If the spring has too many coils or wire diameter is too thick, the spring will go solid before contacting the bump stop.

By adding a spring spacer to the factory spring and a bump stop spacer of the same thickness, the factory spring will not experience any greater stress than with the factory setup (so spring spacers or bump stop spacers). In this situation you have higher ride height but the same up travel or compression as the factory setup. With the OME spring you have the benefit of lift and extra travel as we do not require fitting a bump stop spacer to prevent the spring being overstressed.

Marc your customers should be confident that the maximum stress the spring will encounter when correctly installed for its intended application will be within the maximum stresses the material can handle.

Senior Design Engineer
Old Man Emu
ARB Corporation Limited

------------------------------------------------

Now, all of that being said, I guess if you use OME springs alone to lift your KJ, then you don't need extended bumpstops. They say that they have designed the OME springs to allow for increased travel. No need to limit it by adding extended bumpstops.

But... From what they said, if you are installing a spacer lift (and this would include the OMEs when used in a Frankie) extended bumpstops are needed to prevent over compressing the springs.

There you have it. Let the horse beating begin....

Gee and he probably had to dish out $150,000+ for his degree that some of us already new :wink:

.

long_tall_texan · **Posted:** Mon Feb 09, 2009 11:39 pm

Back-n-Black · **Posted:** Tue Feb 10, 2009 12:48 pm

Great research LTT. That is the kind of facts we can learn a lot from and stop the hear-say.

I think your miss understanding about the OME spring and spacer comment as he stated "

Quote:

he maximum stress the spring will encounter when correctly installed for its intended application will be within the maximum stresses the material can handle.

"

I take that as meaning the spring is designed to be stronger than the forces that our KJ at apply to it, baised on weight and travel. And so even at full compression will not be damaged or sag because of the way the springs are made.

Although i could be wrong.

tonycrd · **Posted:** Tue Feb 10, 2009 1:27 pm

Great research LTT! But the answer is the same as your drawing. LOL

The Franky uses daystar extended topplates so I beg to differ, spring compression stays the same asif there was no puck.

The only thing different is that the spring sits higher on the shock so to say.

With the OME spring you have the benefit of lift and extra travel as we do not require fitting a bump stop spacer to prevent the spring being overstressed .

So you can bang the hell out of OME springs and they won't get damaged?

Bold statement.

Well, I already bought bumpstops and will fit them anyway, better save then sorry.

long_tall_texan · **Posted:** Tue Feb 10, 2009 1:38 pm

Oh yeah, I forgot that they use the Daystar top plate. So I guess in OME's theory, you don't need extended bumpstops for the Frankie either. Hmmmm. I am going to have to chew on that for a while to see if I agree.

tjkj2002 · **Posted:** Tue Feb 10, 2009 1:42 pm

Adding a spacer with the OME coils increases lift height from "pre-loading" the coils more,this puts more stress on the coils and increases the chances of stacking the coils more often if no extended bumbstops are used,stacking is exceeding OME specs for the coils and that's why you lose the warranty on the coils in a Frankinlift.

tommudd · **Posted:** Tue Feb 10, 2009 1:43 pm

hear say ????? interesting statement

Now what the fancy engineer whatever did not state is that"if a spring appears to have been stacked it will not be warranted by ARB/OME" so it can and does happen. Basically he is using a lot of big words to say that we make springs that should last the regular user a lifetime but in fact if its been stacked or abused in any way, no new ones!
My formal spring education came from buying way too many springs and abusing them over the last several years.
So it boils down to
do you buy insurance for your KJ? If so WHY? Aren't you a careful driver and never have had an accident? Bumpstops are the same as buying insurance many will not need them maybe but they are very cheap insurance to protect 150 dollar springs :wink:

oh and times two on what tjkj stated :wink:

long_tall_texan · **Posted:** Tue Feb 10, 2009 1:44 pm

But doesn't the Daystar top plate counteract the pre-load of the spacer?

Bumpstop question

Who is online