There is one more point in the many that I neglected to call out, so I reluctantly must add further to my long list of (apparently) unwelcome comments.

The spring-cut vehicle most certainly can expect to have a reduced weight capacity. This also translates to supporting less of a load in hard cornering, and reduced suspension travel. All that force needs to go somewhere so when the spring bottoms out, it goes to the chassis and suspension components. Not a good thing.

Here is an excellent explanation that I encourage spring-cutters read - it explains the differences between a lowering spring and a cut spring. I think it's clear from the information presented that a lowering spring is the better choice if you want more than just a cosmetic change, and an engineered solution that provides handling improvements, safety, and "the look":

http://craig.backfire.ca/pages/autos/cutting-springs

Cutting springs gives you a lower car, but throws the rest of your suspension design out of whack. It opens the possibility for unsafe conditions (like what might happen if cornering at 140mph and the suspension bottoms out...)

If we're going to dish out advice here, we really owe people reading it to get good advice. Again, I'm sorry if anyone feels slighted, or put down. That's not my goal.

My goal is to help people do it right or realize that doing it right requires saving a little more money and doing a little more homework.

There's nothing wrong with that. It's exactly what I'm doing - saving my money for lowering springs, new shocks, replacement bump stops, and perhaps other things. In the meantime, I'm looking at what other people (that did it right) are doing, learning what works and what doesn't, and adjusting my approach to suit my needs.

That way, when I take the car apart, I can do it right all at once.

 

what do you think a well engineered spring does lowers the car reduced suspension travel your "well engineered" springs lower the car more than my cut springs can you explain.....

 

Thanks for the update. But you said in the linked post that you did have uneven wear. You choose to attribute it to driving conditions and not the suspension. How did you differentiate what caused the uneven wear?

The uneven wear you have is very telling - and supports my contention that cutting springs is a bad idea. Here's why
Read more here http://www.babcox.com/editorial/tr/tr129622.htm

You guys are just not convincing me.

 

I don't feel the need to.

Good luck with your mods and your Crossfire.....

 

I don't understand your question(s?) but will try to respond anyway.

Basically, if you have a shorter spring, it needs to be stiffer (compared to a stock-height spring) in order to prevent the suspension from bottoming out early. If you cut the spring, you reduce the resistance to force and reduce the amount of force required to bottom out the suspension. That means the spring will bottom out prematurely causing handling problems.

Take the time to read the article provided. http://craig.backfire.ca/pages/autos/cutting-springs

There are pictures in the linked article that make it easier to follow along.

 

Chill dudes...Quite a high percentage of degreed ME's get very testy about mere technicians "going with the gut" on something they, or another degreed ME has been paid alot of money to design. Right or wrong.

 

This thread gets better everyday lol

 

Ppro, I agree with you're comments and thoughts and I do respect them. However I did make the decision to cut my springs, reason being after reading through all the forums I came across a few members that said the Crossfire springs and the Eiabach springs have the SAME load rating the only difference is the Eiabach has fewer coils. Based on this I decided that why waste my money when it's the same thing? Your ideas may be well and true for different cars but in the Crossfires case I do believe that it's perfectly fine to cut them with in reason. Obviously if you take of 2 or 3 coils it's going to cause problems but if you do it within reason it's fine. Like I said I did it and I'm 100% happy with every aspect of it.

 

Wow, Jonny, what a thread...I have several, and I do mean several engineering buddies, from electrical, mechanical, and even Civil for those washboards you were mentioning...and I would never involve them in this discussion...from what I have learned...there isn't a big swing in what you are all doing by cutting, in other words, like I stated earlier, you are withing the parameters of the original design of the vehicle when you drop the front an inch or so and the rear an inch or so...so really you are all right in your responses...except Ppro hasn't researched what the parameters are...the strength in the springs losing a half coil is not going to be noticed in a 3200 lb car, maybe in my big rig at 28000 lbs, but not in this little car...I will check my alignment on the rack either way, but cutting is for me...

 

I guess you don't understand the explanation. Yes, the factory and the Eibach and factory spring have the same load rating but that's before you cut the factory spring! After you cut the factory spring you no longer have the same load rating.

 

I don't have the means to give you the actual difference in the before or after cutting but I can assure you it will matter. Since you'll be cutting your springs maybe YOU can tell us how much of change there is?

Oh by the way, (whispering) - The earth is flat...

discuss....

 

I just have one thought on this, and like others have stated. The aftermarket springs are not as stiff as the srt-6 springs. Now if they are not as stiff and shorter that would make them more vulnerable to hitting the chassis in cornering. So by cutting the stock srt springs being they are not progressive and are a lot stiffer how does it make it bad? I am honestly just trying to learn about this and get the correct answer.

 

Why wouldn't you involve them? It would be interesting to have your engineering buddies take a look and give you the benefit of their wisdom.
I don't think your electrical engineer is going to help you much. Your civil engineer might - if he deals with something other than roads and bridges. The mechanical engineer is probably your best bet - after all - this is mechanical...

You don't strike me as the kind of person that does something just because "everybody says it's cool". It seems you'd do some research before you cut away.


This is actually starting to get humorous. Where's Rod Serling when you need him? This would make a great episode of "The Twilight Zone"...

 

Your building your hypothesis on unproven supposition so you can't make a conclusion on it.

Again, read the article at the link I provided. It explains it very well, and has pictures which really help make it easy to understand if you're not a math/engineer type.

 

Here is the article that is at the link I provided. (http://craig.backfire.ca/pages/autos/cutting-springs)

READ


Introduction

Lowering a car is a common practice when trying to improve the handling or the appearance. In some cases, this is done by cutting the springs that came with the car. In this article, I will be looking at the problems caused by using cut springs.

How Springs Work

A spring is a mechanical device that absorbs energy by deflecting a certain distance. Springs have a property called a spring constant which is a ratio of the force applied to the deflection distance. A higher spring constant implies that the spring will have a lower deflection distance for a given applied force.
The magnitude of the force and the spring constant determines the compression distance of the spring.

When the tire of a car goes over a bump, an upward force is sent through the suspension to the springs. The springs will absorb the energy by deflecting by a certain distance, depending on the value of the spring constant and the magnitude of the force from the bump.
Bottoming Out

Due to packaging and other contraints, a car's suspension can only travel so much before bottoming out. When this happens, the spring will no longer absorb any more energy from the bump, and the remaining energy will be sent to the chassis and passengers. This is an unavoidable condition, which is why cars are designed to handle a reasonable amount of force being transmitted to the chassis.
The force that the chassis will receive from the bump is equal to the force of the bump minus the force taken by the spring.

Lowering a Car

The springs play a key role in the car's ride height. The weight of the car itself places a force on the springs, which deflect until all of the force from the weight has been absorbed. At this point, the spring is said to be in equilibrium, and the car will be resting at its ride height.
Lowering a car is as simple as fitting springs which will have a lower total height when the weight of the car is placed upon them. There are two main approaches which can be taken to achieve a different spring height, one is to cut the springs which came with the vehicle, and the other is to replace them with lowering springs.
A lowering spring will be shorter than a stock spring when unloaded, and will have a higher (stiffer) spring constant as well.
A cut stock spring will also be shorter (obviously), but unlike the lowering spring, it will have a spring constant which is basically the same as the stock spring did. However, if the spring was cut using a method which caused the spring to heat up significantly, the spring constant may actually be lower than before it was cut.
Suspension Travel and Chassis Load

A lowered car will have less suspension travel before bottoming out. Because of this, the spring must absorb the same amount of force as the stock spring, but in a shorter distance. This implies that a spring with a higher spring constant must be fitted.
In the example below, the stock spring has a resting loaded height of 10 inches. The car will be lowered 2 inches, using either a stock spring which has been cut or a lowering spring. With the stock spring, the suspension has 4 inches of travel before bottoming out.
Comparison of the three springs.

If the suspension at stock ride height has 4 inches of travel, and the stock spring has a constant of 100 lb/in, then the spring will absorb up to 400 lb of force before the suspension bottoms out.
If the stock spring is then cut so that the resting height is the desired 2 inches lower, then there is 2 inches of suspension travel left. The spring constant is unchanged, so the spring can absorb only 200 lb of force before the suspension bottoms out.
If a 2 inch lowering spring with a spring constant of 200 lb/in is fitted, the spring will be able to absorb 400 lb/in before the suspension bottoms out, as was the case with the stock spring.
Below is a diagram showing the three springs when the suspension has bottomed out.

The cut stock spring takes only 200lb to bottom out, while the stock spring and lowering spring takes 400lb.

 

If a car goes over a bump which creates a greater force than the spring can absorb before bottoming out, then the remainder of the force will be sent to the chassis. Below is the equation for determining the force which would be transmitted to the chassis if the suspension were to bottom out.


The force that the chassis will receive from the bump is equal to the force of the bump minus the force taken by the spring.

In the previous example, the stock spring would absorb 400lb of force, as would the lowering spring. The cut stock spring would only absorb 200lb of force, meaning that a significantly larger force would be transmitted to the chassis when going over large bumps. A car's chassis is only designed to handle a certain amount of force, and the cut lowering spring would be sending a greater force to the chassis.
Because the cut stock spring's ability to absorb energy before bottoming out is so low, the suspension would bottom out much more often than with the other springs. For example, a 300 lb bump force would not bottom out the stock spring or the lowering spring, but it would bottom out the cut spring. Ride quality would suffer as a result of bottoming out frequently.
All materials suffer from fatigue (from the French word fatigué, meaning "tired"), which is failure caused by cyclic loads. In the case of a cut spring, it is placing loads on the suspension and chassis far more often than the car was designed for, which over time could cause component failure, which could be very dangerous.
Effect on Handling

Cut springs also negatively affect a car's handling. When the suspension bottoms out, the chassis is unsettled by the sudden large force being sent to it from the suspension. Because a cut spring will be sending a very large force to the chassis, the car will lose grip more readily. This causes a reduction in handling predictability, and hurts performance on rough surfaces.

Fitment Issues

The ends of helical coil springs are made to be flat so that they fit properly into their retainers, and so the load is distributed evenly around the retainer. Cut springs have an angled end which concentrates the load on the retainer, and in some circumstances could pop out while driving.



Cut springs do not fit into the spring retainer properly.

Conclusion

Cutting springs to lower a car is an attractive option because it is cheap. It is also easy to get the exact desired ride height by cutting small sections until the ride height is correct. However, it cannot absorb forces from bumps correctly, which lowers ride quality, spoils the handling and causes unnecessary wear on suspension components. Cutting springs will in fact lower a car, but so would flattening the tires.

 

Now i am a math/engineer type as you stated, and i also looked over that page with 5 year old pictures for the non educated people. I understand your point but i still have not received an adequate explanation on how the Eibach springs would be better for the srt6 when their load rating is softer than than the factory srt6 springs.

 

Also our spring does not look like the one in your picture.

 

Provide the source for your load rating numbers - forum messages don't count.

I Didn't say Eibach springs would be better for the SRT6. There are a few brands of lowering springs available for the Crossfire - Eibach is just one.

I said lowering springs would be better than cut springs. The write-up explains the reasons.

I didn't draw the pictures so take no pride of ownership. They convey the important points.

Though the springs may not look the same as Crossfire springs the fact remains that if cut, they won't fit properly in the car.

 

Didnt I see a picture of the SRT spring seat that matches the coil twist?? The SRT dosent have a flat seat does it?

MikeR