Cut vs. Reset aftermarket lowering springs

[PDMJO]

Cutting coil springs increases the spring rate plus, since there is less material to absorb the variable loadings, they have a shorter life span ie, prone to sagging earlier. Also cutting only works where the end coils are the same configuration before and after the cut. ie; they may not fit the spring seats. Cold cutting with an angle grinder is the cost effective method.

Resetting the free height of coil springs (if done properly) doesn't change the spring rate or affect their durability. Eibach, H&R and others are cold wound springs using specific spring steel wire specified for cold winding. Resetting is accomplished by heating up the coils and compressing them while hot, then re tempering them to ensure a return to the spring rate. Not an easy process, requires expensive equipment and a lot of experience on behalf of the operator.

It's not advisable to lower a vehicle without at the same time increasing the spring rate to compensate for the decreased suspension travel that is available after lowering. Hence resetting springs is risky, the lower the more the risk of running out of suspension travel. Cutting coils may prove to be the better option (provided they fit the spring seats) and will result in an increase in the spring rate. But in general the increase in spring rate is not proportional to the amount of lowering. It really depends on the diameter of the wire, the number of coils removed and the ID of the spring.

The aftermarket spring manufacturers spend a lot of time and resources determining the appropriate height and spring rate. I haven't designed or even fitted any springs to a Tiguan so I don't know the specs, But having spent some time underneath one designing swaybars I seem to recall that the springs were not parallel in shape and hence probably not suitable for cutting (once cut they may not fit the spring seats).

Cheers
Gary

That’s a good point Gary, something I’ve failed to consider with resetting the springs is the amount of travel would still remain the same, but the ability to absorb that distance would be reduced (in this case by 10mm).

[PDMJO]

It’s illegal, don’t do it (just in case you don’t know that).

You’ll also invalidate your insurance.

I think at the back of my mind I had this hunch as well.

I suppose I was hoping that resetting the springs was right on the line of what you can get away with. That plus the fact that it’s offered as a professional service. Wilful ignorance on my part perhaps!

[Sydneykid]

I think at the back of my mind I had this hunch as well.
I suppose I was hoping that resetting the springs was right on the line of what you can get away with. That plus the fact that it’s offered as a professional service. Wilful ignorance on my part perhaps!

How would anyone know that the springs have been reset? The process is to heat them up to a bit over 1000 degrees, which obviously burns off any paint or markings, compress them to the desired height, retemper them, often also shot peen and then paint. So they look like new springs that no one could tell were reset. So whether its illegal or not is a mute point as no one could possibly prove it one way or the other.

As for cutting, if the springs are parallel then the only evidence is the lack of paint on the end of one coil, which when installed in the car is invisible as it sits in the spring seat. If you are good with a touch up spray can it's invisible. So whether it's illegal or not is again a mute point.

Insurance wise, that depends on your insurance company and applies to any modification you make. If you are concerned, then keep you standard suspension for a quick swap over before the assessor arrives. If they even bother to, most accident repair approvals are done via pictures these days.


Cheers
Gary

[PDMJO]

How would anyone know that the springs have been reset? The process is to heat them up to a bit over 1000 degrees, which obviously burns off any paint or markings, compress them to the desired height, retemper them, often also shot peen and then paint. So they look like new springs that no one could tell were reset. So whether its illegal or not is a mute point as no one could possibly prove it one way or the other.

As for cutting, if the springs are parallel then the only evidence is the lack of paint on the end of one coil, which when installed in the car is invisible as it sits in the spring seat. If you are good with a touch up spray can it's invisible. So whether it's illegal or not is again a mute point.

Insurance wise, that depends on your insurance company and applies to any modification you make. If you are concerned, then keep you standard suspension for a quick swap over before the assessor arrives. If they even bother to, most accident repair approvals are done via pictures these days.


Cheers
Gary

I see where you’re coming from Gary, but if I go ahead with it, I’ll only be getting the rears reset.
From memory the springs are black, so apart from the Eibach branding, maybe with some dust on both sets they’ll appear similar.

[Sydneykid]

I see where you’re coming from Gary, but if I go ahead with it, I’ll only be getting the rears reset.
From memory the springs are black, so apart from the Eibach branding, maybe with some dust on both sets they’ll appear similar.

I'll emphasise something from the first post "if done properly", resetting springs requires the right equipment and an experienced operator to use it. For example, get the temperature even slightly wrong and it will no longer be a "spring", as a result it will sag very quickly. So make sure you use someone suitably equipped and qualified.

Cheers
Gary