I see many posts about the dangers of cutting springs.
Can someone explain the problem if I meet the following two criteria -
I don't affect the temper of the spring when I cut it (no heat).
I fit appropriate length shocks, if required, to ensure the spring remains captive.
BBB
Cut Springs
Started by
_TOBES_
, Dec 02 2006 10:44 PM
49 replies to this topic
#2
dattoman
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Posted 02 December 2006 - 10:48 PM
Bad idea
Just buy the right height ones new or at worst get them reset
Cut springs + accident = lawsuits + innocent victims
Just buy the right height ones new or at worst get them reset
Cut springs + accident = lawsuits + innocent victims
#3
Evan
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Posted 02 December 2006 - 10:56 PM
you can get kings for 110 bucks for a set, any height you want. its a much better idea.
Ev
Ev
#4
_RpM_
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Posted 03 December 2006 - 12:20 AM
Springs are like anything dude, they're designed to do a job, and they have to pass certain tests before they can be used. If you change their properties, then they will no longer pass the requirements for their specific purpose.
As dattoman said also, if you were in a prang, and the suspension was found to be the reason for the accident, there's no-one to blame but yourself.
It's worth it to spend the $100 odd to get new replacements, the right length from manufacture.
As dattoman said also, if you were in a prang, and the suspension was found to be the reason for the accident, there's no-one to blame but yourself.
It's worth it to spend the $100 odd to get new replacements, the right length from manufacture.
#5
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Posted 03 December 2006 - 12:35 AM
Ok.....So there is no physical/mechanical reason why it should not be done, providing the suspension design and setup is sound, and the car is properly certified by an appropriate engineer??
#6
ls2lxhatch
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Posted 03 December 2006 - 12:48 AM
Cutting a spring is still a bad idea. The cut spring may work and may not be dangerous but it will not work as well as a spring designed for the job.
If you were to design a lower spring then you would probably choose a different coil thickness and/or coil rate to provide the appropriate spring properties.
If you were to design a lower spring then you would probably choose a different coil thickness and/or coil rate to provide the appropriate spring properties.
#7
_HemiRana_
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Posted 03 December 2006 - 01:28 AM
Im interested to hear how your going to cut spring steel with no heat?!?!?!?!?!And there is no way known to man,a certified engineer would ok cut springs in a vehicle.If he did Id be the first to dob that f@cker in,laws and guidelines for mods are there for a reason,to protect ppl from dangers created by dodgey backyarders,and to prevent injuries from equipment failure...We all want our cars finished cheap....they just gotta be safe
#8
_TOBES_
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Posted 03 December 2006 - 02:18 AM
So......Everybody says it is a bad idea.....But I still have no reasons why...??
(Its bloody good exercise, but I have cut them with a hacksaw before now)
(Its bloody good exercise, but I have cut them with a hacksaw before now)
#9
rodomo
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Posted 03 December 2006 - 05:59 AM
A physical/mechanical reason:Ok.....So there is no physical/mechanical reason why it should not be done, providing the suspension design and setup is sound, and the car is properly certified by an appropriate engineer??
If you cut the spring, you will end up with the cut end not fitting the saddle correctly and the spring will distort when compressed.
#11
davelh
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Posted 03 December 2006 - 07:58 AM
tight ass
just get new ones
simple
(even go to the wreckers and look)
dave
just get new ones
simple
(even go to the wreckers and look)
dave
#12
Toranamat69
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Posted 03 December 2006 - 09:18 AM
When you cut a spring, besides the fact the spring can be heat effected, you not only shorten it but you also stiffen the spring considerably which means you haven't actually shortened it that much because it will sit a bit higher with a stiffer spring so if you cut some more off to get it that bit lower, then it lowers a bit but then the spring is stiffer again.
By the time you have lowered the car to where you want it, you may well have a spring which is far too stiff for good handling and road holding.
Your spring is then expected to travel over the same range of travel with fewer coils which is more likely to fatigue and crack over time.
M@
By the time you have lowered the car to where you want it, you may well have a spring which is far too stiff for good handling and road holding.
Your spring is then expected to travel over the same range of travel with fewer coils which is more likely to fatigue and crack over time.
M@
Edited by Toranamat69, 03 December 2006 - 09:20 AM.
#13
_bodallafella_
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Posted 03 December 2006 - 11:16 AM
I have cut springs on a few cars including a UC and it works fine. It's one of those things that the wowsers like to get hysterical about but it's really no big deal.
#14
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Posted 03 December 2006 - 11:28 AM
You seem fairly hell-bent on doing it. And so far you've been given every reason not to, but you refuse to listen, why bother posting it?
Im pretty sure that when I said "If you change their properties, then they will no longer pass the requirements for their specific purpose." ... there's both a physical and mechanical reason in 1, not to do it.
A spring isnt just a wound piece of metal. It's rated and designed to react a certain way, and if you change its design, it's not going to work.
Also, cutting it with a hacksaw is still going to heat it up. Friction will heat it past the point of structural change. It doesnt have to be red hot to cause damage.
Im pretty sure that when I said "If you change their properties, then they will no longer pass the requirements for their specific purpose." ... there's both a physical and mechanical reason in 1, not to do it.
A spring isnt just a wound piece of metal. It's rated and designed to react a certain way, and if you change its design, it's not going to work.
Also, cutting it with a hacksaw is still going to heat it up. Friction will heat it past the point of structural change. It doesnt have to be red hot to cause damage.
#15
_TOBES_
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Posted 03 December 2006 - 12:15 PM
Excellent...Now we are getting somewhere...
Does it state in the rules and regs that 'Thou shalt not cut thy springs', or does it go on about springs remaining captive, minimum ride heights, maintaining sufficient suspension travel, etc, etc.
Rodomo - that is a good point about keeping the spring square and straight in its seat and there is no easy way around it. If the spring flattens out at the end then don't cut it...
M@ - I have cut springs in the past to increase the spring rate, rather than to achieve a drop in height, but only by one coil and never on a flattened end. The spring rate curve is expotential rather than linear. Cut one coil from a 10 coil spring and stiffen it by 10%, cut a second coil and stiffen it by an additional 15%, cut a third and get an additional 30% and so on. Three coils equal a 55% stiffer spring! (all figures are approximate...)
Tyring to lower a car a significant amount this way does not work. The law of diminishing returns...
I have never seen any sort of detailed info posted in any forum before and feel that it should be.
I have had some interesting conversations with my son's friends wno all want to 'slam' their cars to the bump stops. They know it looks cool but don't realise the dangers involved...
Keep the comments coming......
Does it state in the rules and regs that 'Thou shalt not cut thy springs', or does it go on about springs remaining captive, minimum ride heights, maintaining sufficient suspension travel, etc, etc.
Rodomo - that is a good point about keeping the spring square and straight in its seat and there is no easy way around it. If the spring flattens out at the end then don't cut it...
M@ - I have cut springs in the past to increase the spring rate, rather than to achieve a drop in height, but only by one coil and never on a flattened end. The spring rate curve is expotential rather than linear. Cut one coil from a 10 coil spring and stiffen it by 10%, cut a second coil and stiffen it by an additional 15%, cut a third and get an additional 30% and so on. Three coils equal a 55% stiffer spring! (all figures are approximate...)
Tyring to lower a car a significant amount this way does not work. The law of diminishing returns...
I have never seen any sort of detailed info posted in any forum before and feel that it should be.
I have had some interesting conversations with my son's friends wno all want to 'slam' their cars to the bump stops. They know it looks cool but don't realise the dangers involved...
Keep the comments coming......
#16
_SSHatch_
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Posted 03 December 2006 - 12:24 PM
The simple fact that its illeagl and if found out your car can be defected should be ample reaon without going into all the mechanics of the changed spring properties. The fact that the pressures exerted on the spring will be different due to the changed suspension geometry.
Take a look at a set of standard springs compared to a set of after market lowered springs. They arent simply lower springs. They have a different number of coils and are made out of different thickness materiels. This is done because lower isnt simply lower. Its also stiffer to stop the car from bottoming out due to being 2 inches closer to terra firma.
Anybody that cuts springs to lower their car cause they are too much of a tightass to spring the cash for a proper set is a dead set tosser and shouldnt be allowed on the road in my opinion.
Take a look at a set of standard springs compared to a set of after market lowered springs. They arent simply lower springs. They have a different number of coils and are made out of different thickness materiels. This is done because lower isnt simply lower. Its also stiffer to stop the car from bottoming out due to being 2 inches closer to terra firma.
Anybody that cuts springs to lower their car cause they are too much of a tightass to spring the cash for a proper set is a dead set tosser and shouldnt be allowed on the road in my opinion.
#17
Toranamat69
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Posted 03 December 2006 - 01:04 PM
Tobes, that is pretty much how it works for increase in spring rate, but only the active coils count in the calculation.
I have changed a few stock springs which had snapped over the years and they weren't even shortened so it does happen sometimes.
You may have gotten away with it in the past but when they design a car, it is designed to be able to be driven for years over corrugated roads and bumps etc without breaking.
I have H/D lovells in mine and I reckon they are already too stiff, when I go coil overs, I am going to soften mine a bit.
They only have about 4 1/2 to 5 active coils too so I reckon if you cut mine down you would end up with a pretty nasty spring for street use, and you would be working the spring around 20% harder than it was designed for.
Wire diameter is the best way to get a heavier spring.
Getting a spring company to reset the height of the spring is the 2nd best way to lower the car. (drop spindle is the best way). That way it maintains spring rate and the distance over which you are working the steel.
Spring stiffness is defined as follows for those maths types.
K=W^4G/(8ND^3)
where W = OD of spring wire (inches)
G = 12,000,000 for steel springs
N = number of active coils (number of free coils + 1/2)
D = average diameter of spring helix (inches)
K = Stiffness of the spring in lbs per inch
M@
I have changed a few stock springs which had snapped over the years and they weren't even shortened so it does happen sometimes.
You may have gotten away with it in the past but when they design a car, it is designed to be able to be driven for years over corrugated roads and bumps etc without breaking.
I have H/D lovells in mine and I reckon they are already too stiff, when I go coil overs, I am going to soften mine a bit.
They only have about 4 1/2 to 5 active coils too so I reckon if you cut mine down you would end up with a pretty nasty spring for street use, and you would be working the spring around 20% harder than it was designed for.
Wire diameter is the best way to get a heavier spring.
Getting a spring company to reset the height of the spring is the 2nd best way to lower the car. (drop spindle is the best way). That way it maintains spring rate and the distance over which you are working the steel.
Spring stiffness is defined as follows for those maths types.
K=W^4G/(8ND^3)
where W = OD of spring wire (inches)
G = 12,000,000 for steel springs
N = number of active coils (number of free coils + 1/2)
D = average diameter of spring helix (inches)
K = Stiffness of the spring in lbs per inch
M@
#18
_Aquarius - LC_
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Posted 03 December 2006 - 02:39 PM
Mmm....Illegal!, That's good enough for me,No is No. 
#19
_TOBES_
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Posted 05 December 2006 - 05:56 PM
Ok....Lets see if I can redeem my reputation, and my engineers, from being 'tight ass bodgy backyarders'....
Take a progressive rate, heavy duty, 'Low' King spring.
Total of 10 coils, 8 coils active.
5 active coils widely spaced, 2 active coils closely spaced and 1 between where the space tapers from wide to narrow.
The closely spaced 'progressive' end is not flat.
Low spring rate is 120lb per inch, high spring rate is 200lb per inch.
What changes if I cut one closely spaced coil from this spring????
Take a progressive rate, heavy duty, 'Low' King spring.
Total of 10 coils, 8 coils active.
5 active coils widely spaced, 2 active coils closely spaced and 1 between where the space tapers from wide to narrow.
The closely spaced 'progressive' end is not flat.
Low spring rate is 120lb per inch, high spring rate is 200lb per inch.
What changes if I cut one closely spaced coil from this spring????
#20
_SSHatch_
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Posted 05 December 2006 - 06:00 PM
The tag on it that used to say legal low spring now says Illegal Butchered spring.
Thats about as much as is needed.
The law is the law.
Thats about as much as is needed.
The law is the law.
#21
_SSHatch_
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Posted 05 December 2006 - 06:42 PM
I think that the main thing to be considered here is that a large number of people read these forums and we dont need to go giving them ammunition about why there may possibly be nothing wrong with their Makita Super Lows they just fitted.
I know of business that have been questioned in regards to fitting cut springs to a vehicle.
This occured not long after a teenager was killed in an accident and the investigatoon uncovered the fact that the springs fitted had been cut and completely altered the characteristics of the way the vehicle handled.
So I say its best to not get into all the technicalities of it and arm these youngsters with info that they dont fully understand.
I know of business that have been questioned in regards to fitting cut springs to a vehicle.
This occured not long after a teenager was killed in an accident and the investigatoon uncovered the fact that the springs fitted had been cut and completely altered the characteristics of the way the vehicle handled.
So I say its best to not get into all the technicalities of it and arm these youngsters with info that they dont fully understand.
#22
_TOBES_
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Posted 05 December 2006 - 07:16 PM
The other viewpoint is to fully inform them of all the facts and educate them in the reality of modifications they will likely do anyway.
Perfect case ...
One of the my boys friends appeared over the weekend to show off his car. No licence for 6 months so he had spent the time on his old school Corona. Nice red paint, immaculate cream and chocolate interior, 18" chromes and sills 2" from the road...!
Squeezed an eyeball under the back bumper and saw 3' blocks and the bumpstops 5mm from the axle, couldn't see under the front but it's missing some coils...
"Hey jordy, how does it handle?"
"Ummm..Not too bad..."
"Be like driving a pogo stick, wouldn't it?"
"Well.."
"Whats she corner like?"
"Ummmmmmm...Ok......"
"Come here sunshine.........!!"
Made him read this thread and a couple of others on here and he realised that it was not only an old fart preaching...
Upshot of it is, he isn't going to change the suspension, but he now knows how it will react in a corner and that it will likely bite him one day.
He listened to his mates because he couldn't get the info anywhere else.
Perfect case ...
One of the my boys friends appeared over the weekend to show off his car. No licence for 6 months so he had spent the time on his old school Corona. Nice red paint, immaculate cream and chocolate interior, 18" chromes and sills 2" from the road...!
Squeezed an eyeball under the back bumper and saw 3' blocks and the bumpstops 5mm from the axle, couldn't see under the front but it's missing some coils...
"Hey jordy, how does it handle?"
"Ummm..Not too bad..."
"Be like driving a pogo stick, wouldn't it?"
"Well.."
"Whats she corner like?"
"Ummmmmmm...Ok......"
"Come here sunshine.........!!"
Made him read this thread and a couple of others on here and he realised that it was not only an old fart preaching...
Upshot of it is, he isn't going to change the suspension, but he now knows how it will react in a corner and that it will likely bite him one day.
He listened to his mates because he couldn't get the info anywhere else.
#23
ls2lxhatch
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Posted 05 December 2006 - 07:16 PM
If it fails on a public road then one of the following could happen.What changes if I cut one closely spaced coil from this spring????
1. You die.
2. You live but kill or injure others and become somebodies bitch in jail.
3. Nobody gets hurt and you realise what a stupid idea that was.
If it does not fail but you are involved in a major crash.
1. Crash investigators discover the altered springs claim they were a contributing factor to the crash. Your insurance company does not pay for you car or any other cars leaving you with a significant debt or bankruptcy.
If you are willing to take all these risks to save a few bucks then you should consider psychiatric help.
If you are doing it because they do no make springs low enough then you should consider why? It is most likey because of one or more of the following.
1. They are dangerous
2. Impair handling
3. Not practical because of speed humps.
#24
_TOBES_
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Posted 05 December 2006 - 07:32 PM
This modification has been designed with the help of an accredited engineer, will be certified by another accredited engineer (they are not allowed to cert their own work) and will be listed on the cars mod papers.
The car will be put over the pits and inspected and approved.
It will be listed on the vehicle certification plate.
This will make the mod as legitimate and as legal as any other approved mod to this car or any other on the road.
I have never encouraged any illegal or dangerous modification.
Can you answer the question above???
The car will be put over the pits and inspected and approved.
It will be listed on the vehicle certification plate.
This will make the mod as legitimate and as legal as any other approved mod to this car or any other on the road.
I have never encouraged any illegal or dangerous modification.
Can you answer the question above???
#25
_SSHatch_
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Posted 05 December 2006 - 07:43 PM
I give up!
Cant be bothered arguing with you as you obviously have you mind made up that we are all wrong and your going to do whatever the hell you feel like anyway.
Good luck with whatever the hell it is that gets you off just please let me know if and when you ever get it on the road so I can tell my children to stay at home as the roads are once again inhabited by illegal unroadworthy cars.
I dont care what engineers certificate you flash around, the law is the law.
Loopholes and the like dont protect innocent road users.
Cant be bothered arguing with you as you obviously have you mind made up that we are all wrong and your going to do whatever the hell you feel like anyway.
Good luck with whatever the hell it is that gets you off just please let me know if and when you ever get it on the road so I can tell my children to stay at home as the roads are once again inhabited by illegal unroadworthy cars.
I dont care what engineers certificate you flash around, the law is the law.
Loopholes and the like dont protect innocent road users.
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