Chopping springs for dummies

[adamwatson]

Just found out my insurer will only add £19 to my premium for a lowered car

So I plan to get lowered springs but I'm skint at the moment so I'm going to cut what's there. I want to go down about 45mm so if I measure down the spring whilst loaded as normal 45 mm, draw a line, jack up, cut on line that should drop it 45mm right?

[rmad]

What car is it?

I have to say, based on your question and suggested method, that if lowered springs are available for your car, you should probably buy them when you've got the money.

[adamwatson]

I plan to buy them eventually, just impatient.

It's an E38 BMW 7, quite a heavy beast so I'm not holding out much hope for ride quality on cut springs

[MrSpeedy]

It depends where the springs are located on the lower arms. IIRC Mac struts up front?
Amount cut off = drop when springs are at the extremeties of the suspension links. ie, close to the hub.
If the spring is mounted further inboard (like it is on Mercs, but I'm not familiar with Bimmers) then the drop is proportional to the relative position of the spring along the wishbone/lower arm.
ie, if the spring is halfway between inner mount and outer link/hub mount, then the drop will be approx double the amount you chop off the spring due to the physics of levers/mechanical advantage etc

[daddy]

You'll probably only be able to seat the spring properly with 1/2 coil cut at a time. I say take out a coil and see if you like it, then keep going 1/2 coil at a time until happy

Remember if you go nuts with the chopping the coil won't locate when the car is jacked up or if you get airborne. so you'll need to lockwire or cabletie it to the strut

Best way to cut them is removing them from the car. I realise this is a ballache. Last time I cut some springs i compressed them first on the car and whipped the end off with a cutting disc on the grinder (1mm inox special)

MOT man isnt likely to share your passion for low-cost-lowness and will fail or give an advisory for broken springs

And it will ride pretty curse word without shortened shocks to match. but I still say - get chopping

[adamwatson]

Nov 5, 2012 16:30:26 GMT MrSpeedy said:

It depends where the springs are located on the lower arms. IIRC Mac struts up front?
Amount cut off = drop when springs are at the extremeties of the suspension links. ie, close to the hub.
If the spring is mounted further inboard (like it is on Mercs, but I'm not familiar with Bimmers) then the drop is proportional to the relative position of the spring along the wishbone/lower arm.
ie, if the spring is halfway between inner mount and outer link/hub mount, then the drop will be approx double the amount you chop off the spring due to the physics of levers/mechanical advantage etc

Good point, will do a bit of measuring and sums to get it right

[rmad]

Nov 5, 2012 17:18:26 GMT @daddy said:

MOT man isnt likely to share your passion for low-cost-lowness and will fail or give an advisory for broken springs

Cut springs are not an MOT fail. Having said that, you'll most likely not win the debate if you're trying to explain that to a tester that's just failed your car!

[dreadnought]

Your insurer may accept lowered cars, but tell them you want to chop the spring yourself and see what they say.
Not to mention that god forbid you have an accident and your car gets inspected, they will screw you to the wall, and you will be liable for any claims you or any third party have against you,
Now i know it's a method a lot of people use, and I'm not saying it's a total no no, but it needs to be done well and by some one with experience of doing it.
If you can get real lowering springs then sell some stuff and do it right.

[will]

[dickdasterdley]

E38 fronts are pigtailed at both ends....you can't chop them.....

[adamwatson]

Nov 5, 2012 21:09:17 GMT dickdasterdley said:

E38 fronts are pigtailed at both ends....you can't chop them.....

That may rain on my parade somewhat. I was under the impression they were straight.

[lemon]

Ive heard of people heating the spring whilst compressing it with a clamp, only near the ends of the coil where the springs get closer together, but I cant say for 100% that its safe as I don't know if the spring would be prone to cracking/snapping??

Maybe someone on here has done similar?

[MrSpeedy]

Nov 6, 2012 19:21:52 GMT lemon said:

Ive heard of people heating the spring whilst compressing it with a clamp, only near the ends of the coil where the springs get closer together, but I cant say for 100% that its safe as I don't know if the spring would be prone to cracking/snapping??

Maybe someone on here has done similar?

Don't do this!!!!!!!

Whatever you do/have heard etc DO NOT HEAT tempered spring steel (what all springs are made from). You will destroy all the spring qualities

Nuns and kittehs will burn!

[lemon]

Yes Thought as much, the only part about it I found believable was the fact that only the end was to be heated and closed up together. Thanks for clearing that one up!

[`state]

I recently bought an Astra that the previous owner had cut the springs in half then put the halves inside each other. Then cable tied them together to make a spring half as long as intended.
THE worst and most dangerous bodge I've ever seen on a car.

[dickdasterdley]

Nov 6, 2012 7:01:05 GMT adamwatson said:

Nov 5, 2012 21:09:17 GMT dickdasterdley said:

E38 fronts are pigtailed at both ends....you can't chop them.....

That may rain on my parade somewhat. I was under the impression they were straight.

Sorry for the rain! They're barrel shaped- really fat in the middle and small at either end...

[chairchild]

Nov 7, 2012 9:44:15 GMT `state said:

Then cable tied them together to make a spring half as long as intended.

and FOUR times stiffer

Would've been rather scary to drive I bet!

[kevfromwales]

on my 100e, the springs had been chopped, and welded to the spring cups - which I thought couldn't be beat - until I got some 105e struts in a joblot from rmad's father in law - the springs had been clamped together, then welded!! the bottom 2" of the spring was a solid chunk of metal!

[ChasR]

Nov 7, 2012 9:44:15 GMT `state said:

I recently bought an Astra that the previous owner had cut the springs in half then put the halves inside each other. Then cable tied them together to make a spring half as long as intended.
THE worst and most dangerous bodge I've ever seen on a car.

But did any kittens die? .

[`state]

No kittens,or nuns this time but it was an accident waiting to happen. The tyres had being rubbing on the inner arch so much it was paper thin. I drove it from ferry bridge down the m62 to hull and it rubbed even going over the cats eyes.
The fronts were so short you could twist the spring round and lift it up and down a couple of inch even with the cars weight on the strut.
I've nothing against chopped springs as long as done safely and they seat right but that was going too far. The back end just wanted to slide out at every chance.
Didn't help it was still on standard shocks too
Could have easily ended in a bus stop full of nuns getting knocked down all clutching a kitten each.