Eco diesel Suspension bottoming out on normal roads

[Renegade]

But does the actual length of the spring itself change when you have a 1” spacer?

The measured compressed height of the spring will stay the same, as long as the height of spacer is such that the ride height remains in a position which still allows for suspension extension/droop. If for some reason someone added a crazy-sized spacer, you could create a scenario that the spring was more compressed, and ride height would be at the maximum extension of the shock. That would be horrible...

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[CerOf]

The measured compressed height of the spring will stay the same, as long as the height of spacer is such that the ride height remains in a position which still allows for suspension extension/droop. If for some reason someone added a crazy-sized spacer, you could create a scenario that the spring was more compressed, and ride height would be at the maximum extension of the shock. That would be horrible...

So, if the compressed length stays the same, then there is no additional pre-load.

 

[Renegade]

So, if the compressed length stays the same, then there is no additional pre-load.

Preload is measured without weight on the spring. If we are talking unloaded, then yes, the measured height of the spring with the spacer added will be shorter than without the spacer.

 

[CerOf]

didn’t you say adding a 1” spacer would increase pre-load under the static weight of the Jeep?

If this is true, the spring would have to compress and have a smaller length.

fhe reality is, the spring remains the same length under the weight of the Jeep, even with a 1” spacer.

Thus, there is ZERO additional pre-load.

 

[Renegade]

didn’t you say adding a 1” spacer would increase pre-load under the static weight of the Jeep?

If this is true, the spring would have to compress and have a smaller length.

fhe reality is, the spring remains the same length under the weight of the Jeep, even with a 1” spacer.

Thus, there is ZERO additional pre-load.

YOU DON'T MEASURE PRELOAD WITH WEIGHT ON THE SPRING!!!
This is ridiculous. I'm taking a break...

 

[CerOf]

YOU DON'T MEASURE PRELOAD WITH WEIGHT ON THE SPRING!!!
This is ridiculous. I'm taking a break...

Per accutune, adding preload compresses the spring.

my point is, a 1” spacer can not increase the preload on a JT at static height.

I read accutune’s article on preload.
It’s about coil overs. https://accutuneoffroad.com/articles/spring-preload-matters/

at full droop, the spring will have more load, but that does nothing to help the OP with bottoming out.

 

[Renegade]

Per accutune, adding preload compresses the spring.

my point is, a 1” spacer CAN NOT increase the preload on a JT. The spring does NOT compress, shorten, as a result of the spacer.

I read accutune’s article on preload.
It’s about coil overs. https://accutuneoffroad.com/articles/spring-preload-matters/

Yes, yes it will. You have a fixed distance between the upper and lower spring perches with the shock extended. Let's say that hypothetical distance is 12 inches. Let's also say that the spring itself is 13" long when laying on the ground. When installed, you have 1" of preload, and the spring is measured at 12", because that is all of the space you have available. If you throw a 1" spacer in there on top of the spring now, the spring can only take up 11" of space, where it had 12" of space available before the spacer. The spacer has increased the preload on the spring by 1". This is all done WITHOUT weight on the Jeep. End of story.

 

[olecarguy]

Yes, yes it will. You have a fixed distance between the upper and lower spring perches with the shock extended. Let's say that hypothetical distance is 12 inches. Let's also say that the spring itself is 13" long when laying on the ground. When installed, you have 1" of preload, and the spring is measured at 12", because that is all of the space you have available. If you throw a 1" spacer in there on top of the spring now, the spring can only take up 11" of space, where it had 12" of space available before the spacer. The spacer has increased the preload on the spring by 1". This is all done WITHOUT weight on the Jeep. End of story.

Wow guys. Maybe I can help?.... Assuming one doesn't change the laws of Physics or the Earth's gravitational forces exerted, Renegage is correct in that PRELOAD is done on coil overs without any weight on them. When setting up coil overs, typically 1" of preload is dialed in as a good starting point without any weight on them. However, at this point the shocks are fully extended to their limits containing the springs in the coil over so compression can be added. Then when the vehicle is lowered and weight is put on the coil over, the resulting "compression" is the ride height compression which is a function of the vehicle weight on that corner.

CerOf is also correct in that by placing a spacer on top once DOES NOT change the PRELOAD. Here's why. If there is zero weight on the spring, it can't be compressed. Therefore, there's no PRELOAD. Now, if one is calling the amount of compression exerted on the spring in order to install the shock, then yes one could consider this preload. However, this preload is a function of how much pressure you need to exert on the bottom of the spring to compress it enough to connect the shock. This is using the vehicle weight to accomplish it. You are using vehicle weight to compress the spring, although you may be be raising the vehicle at this particular point in time. It is not compressing the spring without weight on it like with a coil over. This is using some of the ride height available in the spring to accomplish as with a coil over. But in this case once the full weight of the vehicle is on the spring it compresses the rest of the way to the ride height.

So, now that the vehicle weight is on the ground, and we're not a full shock extension, adding a space between the top of the spring and the vehicle does not change the PRELOAD since the vehicle raises an equal amount, and the spring ride compression remains the same, until one reaches a point of full shock extension. If your riding around at full shock extension at rest, then you need longer shocks.

 

[Clayton Off Road]

I wonder if there is a way to Frankenlift the MOPAR 2” diesel lift for the front springs, and the rest of a 2” full suspension lift from another company like Clayton or pick your favorite kit, but excluding the front springs?

personally, I’d rather go with the Clayton 2.5” overland kit, but they don’t make one for the diesel specifically.

Coming soon!

 

[Renegade]

Wow guys. Maybe I can help?.... Assuming one doesn't change the laws of Physics or the Earth's gravitational forces exerted, Renegage is correct in that PRELOAD is done on coil overs without any weight on them. When setting up coil overs, typically 1" of preload is dialed in as a good starting point without any weight on them. However, at this point the shocks are fully extended to their limits containing the springs in the coil over so compression can be added. Then when the vehicle is lowered and weight is put on the coil over, the resulting "compression" is the ride height compression which is a function of the vehicle weight on that corner.

CerOf is also correct in that by placing a spacer on top once DOES NOT change the PRELOAD. Here's why. If there is zero weight on the spring, it can't be compressed. Therefore, there's no PRELOAD. Now, if one is calling the amount of compression exerted on the spring in order to install the shock, then yes one could consider this preload. However, this preload is a function of how much pressure you need to exert on the bottom of the spring to compress it enough to connect the shock. This is using the vehicle weight to accomplish it. You are using vehicle weight to compress the spring, although you may be be raising the vehicle at this particular point in time. It is not compressing the spring without weight on it like with a coil over. This is using some of the ride height available in the spring to accomplish as with a coil over. But in this case once the full weight of the vehicle is on the spring it compresses the rest of the way to the ride height.

So, now that the vehicle weight is on the ground, and we're not a full shock extension, adding a space between the top of the spring and the vehicle does not change the PRELOAD since the vehicle raises an equal amount, and the spring ride compression remains the same, until one reaches a point of full shock extension. If your riding around at full shock extension at rest, then you need longer shocks.

Agree, with some minor semantics differences.

 

[CerOf]

We’re coming at this two different ways.

Ive read your posts in helping the OP with bottoming out that a 1” spacer will help.

Agree, with some minor semantics differences.

First two drinks on me!
(I’d buy more but between three kids in private school and a Jeep habit, gotta pinch pennies somewhere.)

 

[Renegade]

 

[EcoDiezLN]

You raised your ride height, but decreased your overall suspension travel. This is because of the added bump stop spacer you added without increasing the shock extension.

I’ve heard some people don’t use the included bump stop extension without any issues, was thinking of trying that out wouldn’t that give me a little extra room before I bottom out?

 

[Renegade]

I’ve heard some people don’t use the included bump stop extension without any issues, was thinking of trying that out wouldn’t that give me a little extra room before I bottom out?

You can raise your ride height with a spacer. You have to be careful not to raise it so much that you don’t have sufficient droop. Teraflex apparently feels that you can raise the front 1.5” without shock extensions or longer shocks (I think that’s a stretch, but 1” is reasonable). The bump stop extension (without longer shocks/extensions) is to prevent larger tires from getting into the fenders.

 

[CerOf]

You can raise your ride height with a spacer. You have to be careful not to raise it so much that you don’t have sufficient droop. Teraflex apparently feels that you can raise the front 1.5” without shock extensions or longer shocks (I think that’s a stretch, but 1” is reasonable). The bump stop extension (without longer shocks/extensions) is to prevent larger tires from getting into the fenders.

I’ve also heard over compressing a coil is bad, too. Bump stops help with that.

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