Cutting a coil for minimal low?

[Silentnoise713]

I'm also one who would like to lower the car just a little b/c we can get a good bit of snow in these parts. Since there are NO other options out there, this is the only reason why this even crossed my mind. The idea is to cut one coil off the stock springs for a slight drop (guestimate/targeting for somewhere in the ~ -1" ball park). I don't know how the OE springs are wound at the ends (top or bottom) to safely allow this but this would be a cheap solution. Yes there are cheap coil-overs but I'm only bring this up for discussion. Just a though at this point of cutting 1 coil on all four corners + modify or aftermarket bump stops + GR2 for the budget setup.

On my previous car I had a pair of cheap Sprint springs that gave a 2" drop paired with AGX. The rear end was not even so I had a coil cut off. Result was even drop and IMO rode better than before. The sprint springs had close wounds at the top coil so cutting one off still gave me an even top coil to safely mount on the spring perch. Its my understanding that cutting coils raises the spring rate (slightly). Less coils, less deflection, more rate BUT less distance to absorb the load so more work on the shocks and more likely to hit bump stops.


Some things to consider:
-length of the OE springs uncompressed
-pics of the OE springs to confirm if top or bottom can safely remove one coil yet still leave a level coil.
-length of the OE shock uncompressed + top mount b/c this length must be SMALLER than the length of the potential cut spring to ensure they won't 'fall out' under full droop, to ensure they are always under compression.
-to calc http://ls1tech.com/forums/12013793-post23.html


Now, anyone have a pair of OE front and rear springs lying around that can help take some pics and measurement?

 

[Tamn]

There are many companies who will make custom springs for your application for about the same price as "pre-defined" springs.

I've heard good things about http://www.eatonsprings.com/

I believe Eibach also sells custom springs for not much over the price of non custom ones...

Anyways just a thought, I would never cut an automotive spring, its just not worth it. **my opinion take it or not**

 

[Silentnoise713]

I've never had custom springs made before. I will check with Eaton to see how much they can do a set for. If a set can be made to my specs for not much money (~$200-250) then this is definitely the way to go. The alternative is free so it's "worth" it - I kid.


Another thought crossed my mind. Most OE springs tend to have very sparse wounds so even cutting one coil may result in more drop than I'm shooting for. I am thinking back to my experience with Sprint springs which had tight wounds and higher spring rate so cutting one coil worked out great; OE springs may not work out so well. As long as the springs are under compression and you have the proper shock and stop setup that can handle it, it is safe.

 

[Silentnoise713]

Scratch it. Took a look at the suspension diagrams and can pretty safely conclude cutting a coil off OE springs is not going to work well - LOL. Topic closed.

Did send an email to Eaton so let's see what they have to offer

 

[kw_da]

Don't know much about these, but here are some springs you might find of interest

http://www.therpmstore.com/store/c/157-Suspension.html

 

[Silentnoise713]

Don't know much about these, but here are some springs you might find of interest

http://www.therpmstore.com/store/c/157-Suspension.html

Thanks for the suggestion. I should have clarified earlier that I meant no one offers an out of the box spring that drops 1” or less for the Mz5.

Though I have never used H&R, I read they are very streetable, similar to Eibachs. Heavily marketed in the DTM race series. Vogtland is the only other manufacturer that offers a Mz5 specific setup but a little bit lower at -1.5” and rides firmer. I actually changed out the Sprints to Vogtlands b/c -2” was too low. H&R and Vogtland are both Germany made btw.

Also, you can find cheaper vendors for the H&Rs by Googling it.

 

[Davicho]

I had H&Rs on stock shocks and I can testify that H&R springs are great. They ride as nice as OEM.

 

[phunky.buddha]

Hiya

You can cut a coil off the OE springs and still have them seat correctly since they're not wound to a flat at the bottom- but I think you'll drop significantly more than an inch. The free length of the rear spring is about 14.5" but it only has about 8.5 to 9 coils, so cutting one off would probably drop you quite a bit more than an inch. I guess I need to get off my ass and measure underneath the car...

 

[phunky.buddha]

The front would be a little more difficult. I don't have them here, but they're not straight springs- they taper out so they're not a perfect cylinder to work the with Mac strut front end. The rate may be progressive too- haven't measured yet.

 

[the_saint]

I've *heard* that you shouldn't cut coils because:
1) it throws off the spring rate and could cause inconsistent rates between all 4 springs. I guess that could make the car oscillate on bumps causing loss of control.
2) the heat generated can mess with the strength of the spring potentially causing them to [worst case scenario] break while driving.

 

[qcoffey]

I've *heard* that you shouldn't cut coils because:
1) it throws off the spring rate and could cause inconsistent rates between all 4 springs. I guess that could make the car oscillate on bumps causing loss of control.
2) the heat generated can mess with the strength of the spring potentially causing them to [worst case scenario] break while driving.

Agreed. With a linear rate spring, cutting might not have as drastic of an effect. It the springs are progressive rate, they would most likely be unbearable, and probably not safe. I cut a set of Eibach springs on an old Protege about 20 years ago, and the ride turned to crap and was not safe to drive.

The front springs are also tappered on the front and if you cut a coi from the top or bottom, it might not seat correctly.

I've seen companies like Road Magnet do some custom would stuff. Also, an Eibach Pro-kit or H&R Sport are usually not very aggressive drops. Good Luck.

 

[phunky.buddha]

I've *heard* that you shouldn't cut coils because:
1) it throws off the spring rate and could cause inconsistent rates between all 4 springs. I guess that could make the car oscillate on bumps causing loss of control.
2) the heat generated can mess with the strength of the spring potentially causing them to [worst case scenario] break while driving.

1. A staggered spring rate won't make your car do this- blown shocks with no damping will cause this. If uneven spring rates would cause oscillation and loss of control, then so would loading your car unevenly. I hope you have an even number of kids, because then two parent and one kid on one side of the car will cause oscillation in this case. But uneven rates is not good left/right.

2. Cut slowly. But yes, it's pretty much impossible to control the change in material properties when you cut springs.

Agreed. With a linear rate spring, cutting might not have as drastic of an effect. It the springs are progressive rate, they would most likely be unbearable, and probably not safe. I cut a set of Eibach springs on an old Protege about 20 years ago, and the ride turned to crap and was not safe to drive.

The front springs are also tappered on the front and if you cut a coi from the top or bottom, it might not seat correctly.

I've seen companies like Road Magnet do some custom would stuff. Also, an Eibach Pro-kit or H&R Sport are usually not very aggressive drops. Good Luck.

You can cut the fronts at the top of the coil- only the bottom of the coil tapers in to meet the lower spring perch. Still not a good idea though.

 

[Silentnoise713]

Agree it is a bad idea. After posting this, I took a look at the diagrams and noticed what you folks have pointed it. Sparse coils so cutting one will drop significantly more than what I’m shooting for. Tapered end will also mean it will not seat on the perch properly. I’ve read some hardcore folks heat teat the cut end and essentially bend and reforming the end of the spring to fit the perch. This may mess with the structural integrity of the metal and I would not want to find out.

There are folks who take the cutting route. Most of the terrible ride stories seem to stem from people who do this on the cheap and NOT replace with stronger shocks or more importantly modifying the bump stop for the lost suspension travel, hence the ride like arse.

If Mz5 rear springs are 200 lb/in and 9 coils, cutting a coil would result in springs that are 225 lb/in on eight coils.



Quote below is the response I got back from Eaton, which I find very intriguing. Yes I was asking about a Mazda5 and it ‘sounds’ like they’ll take a pair of Mazda3 springs and modify it to suite what I’m asking for the Mazda5. Thinking out loud, I wonder if they’ll just cut (maybe less) the Mazda3 spring and stretch it out or something on a machine to get the required height? They are the spring experts so I would assume their solution is reliable but sure does make me go hmmm… I thought they would build a custom set. Anyway, at $189.95/pair x 2 + S/H = easily over $400 for a set of modify OE springs. WAY more than I want to spend...

We have the stock 2008 Mazda 3 springs for $159.95 a pair in the front and also $159.95 in the rear we can make them 1 or 2 inches lower for $189.95 per pair plus shipping the rate will increase about 15% over stock. Sorry, I do not have those numbers. They are not returnable.

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[phunky.buddha]

Wow. That's a bit expensive. Give me a little more time- trying to finish procrastinator taxes and finish out house plumbing at the same time.