Cutting down springs, got any info?

Moschops

Moschops

Ex. Club Member
Club Member
I'm a fan of having a go at things myself being a farm boy, and as I'm a bit too strapped to buy some lowering springs now I wondered if anyone could advise on the why's and wherefore's of doing this.

Getting them on and off is ok but do I have to cut them so they end in the same place...like so they sit on the platforms the same? How much do I cut off for, say, 30-50mm drop? Will the ride be harder, softer, will the springs move about etc?
Has anyone done this and got any pics?

Just testing the water at the mo but i'm already itching to get the grinder out!

thanks.
 
I'm pretty sure it's illegal to cut your springs - but good luck, I might try this in the future.
 
its illegal to do it because..

1. It dramaticly effects spring rates...
2. You wont be cutting the same amount of each side so each corner will react differently
3. The springs were designed at the lengh they are already. Altering it even by a coupld of CM can put the whole spring out. It will make the ride very VERY bouncy and will handle like a boat
3. If the springs are in a cone shape, then you run the risk of the spring not sitting properly and they can jump off the shock
4. As the result of the above, it will make the car VERY dangerous and has the potential to catch you out when you least expect it and at some speed...
 
That's fair enough then, I didn't realise it was illegal.

What am I going to do with this grinder then...? :D
 
tbh honest mate i dont think it is illegal but it would make the ride very bouncy and prob make you ill. and yeah its not the safest but i dont think that you would crash, i know a couple of tits who did it and they didnt bin there cars. but i would not advise it, it will make ur car handle worse and its extremly dodgy
 
the kid i got my first super s off cut the springs and had no problems with them,,just dont go too far or they will pop out of the holders
 
i think the only issue with this is there not a uprated spring rate so cutting a coil off and putting them on wont do any harm (you have to cut it at the same point where the spring stops) but the ride will be as sloppy as having the stock springs in, there is a chance then that the shocks will bottom out.

i dont think the micra k10 or k11 has a progressive spring rate so it wont matter cutting 1 coil off, if its just a stop gap untill you get proper uprated springs id say do it

does anyone know the standard spring rate - i think ive asked this before lol
 
it's very dangerous and i don't recommend it but if you do cut them then take it to a garage to get the geomotry checked out to make sure the car is riding right before you do any high speed runs.

lowering springs are stiffer too to compensate so you could run into all kinds of trouble from scuffing to recoil...

your choice mate :)
 
There's so much rubbish in this thread. Firstly, it isn't illegal. There are very few modifications to cars in the UK that are illegal as long as they are done safely.

Removing length from a spring increases rate. This gives a stiffer and lower ride. You lose travel though, but this is compensated for to a certain extent by the increased rate.

However, your insurance company won't touch it with a bargepole...
 
And also the dampers may extend far enough that the springs fall out of their cups.
 
Ed said:
And also the dampers may extend far enough that the springs fall out of their cups.
Click to expand...
most of the people on the powercoil group buy have been affected by that im sure..
 
How many on here have actually rode in a cut spring car or even know anyone who has?
Anyone have any proof it being illegal?
Would be nice to see facts before people through info out there which will obviously sway his decision whether to do.

I'll see about a ride in mates car with cut springs and see for myself but I'd say get a spare set and see what you think.
 
If it's illegal how come Revs and MP use to always have the project cars slammed to the ground with cut springs.

Any one seen the Vaux Cav Vs BMW 5 - they cut the springs - so much so it had a 120mm drop!
 
I didn't think it was illegal. And with the risk of the shocks, don't you have that risk with even if you buy shorter springs. The only reason I see against it, is the lack of accuracy
 
come to thing of it i think it is illegal and it wont pass a mot, theres no accuracy in it, the way to do it is cut it at the same place where the spring ends but a coil up

i know quite a few people who have cut springs, i know a volvo that has the springs cut with no problems and he drifts it, and another mate who has cut his lowering springs with no probs.

not saying its the best way but it can be done
 
Maybe lowering springs are the same length as standard it's just the rate that's different so it sits lower when compressed? As long as the spring do not move on the platforms (loaded or unloaded) and the shocks are ok then from a safety point of view it would be the same as fitting lowering springs.

I guess it's therefore insurance that would worry me.
 
How does shortening a spring increase it's rate, is that not related to Hooke's law, as all you are doing is shortening the length, not altering the stiffness constant?
What is the law regarding to car parts being BSS compliant/inspected, that is one thing that sometimes concerns me with modifying, but at the end of the day I suppose that as long as the nsurer knows and is ok about it, then it does not matter.
Surely it will wear dampers out+more chance of bottoming out than proper lowering springs as they will be stiffer, so will put up more resistance than OEM ones which are designed to be x coils higher and softer.
 
Take 1 active coil. It compresses 10mm for every kg (10mm/kg). If you have 10 of the same coils, they will compress 100mm for every kg (100mm/kg). Hence if you reduce the length of the coil, you end up with an increased spring rate. Simple mechanics.

Hooke's law is normallised over length of the material. Spring rate is dependent of length of material, which is why you have a difference.

The lowering springs I have fitted previously have had a progressive rate. The first few coils have a very low rate, so they stay in contact with the perches but don't effect the suspension.
 
Ah, that makes sense, didn't know how to calculate spring lenth and thought it was just a matter of basic elasticity.
Do the tighter wound springs at the top have a different rate then as they are shorter, but made of the same material?
 
sometimes its the only way as you cant get lowering springs for some rare models.

back in the 1970's rally teams used to cut thier springs etc and so did some sports tuning companies for lower stance and improved handling. If done properly then it is a good cheap way to drop a cheap ride.

Dont bother on a skyline or something lol.
 
its not illegal, micra springs have holders if cut correctly they will sit in the holder with no problem at all, the ride is exactly the same as when they are not cut your car sticks to the ground like hell and doesnt want to slide as much............ you just have to cut the same lenght or u could be lower on one side then the other

if you do it, let us know how it works out
 
if I remember rightly.... on either the front or the back, there's a coil at the top or bottom that comes round so it's flat.... and doesn't end on a coil.

You may need to find someway of recreating that
 

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