NC Lowering - Newbie question

[Tezzax5]

check your pm's.....

[Garry]

You will need to budget in a 4 wheel alignment after it's lowered to avoid uneven tyre where and some funky handling issues. You might like to keep in mind that the minimum legal ground clearance when fully laden is 100mm in most states of Australia. This may determine how low you can legally go.

[Charlie Brown]

Murphster,

There’s not a lot of difference between 30 and 40mm lower in appearance and I agree with you that 40mm is too low for general road use. Sure it looks great but some care is needed when negotiating speed humps, dish crossings and those one way metal finger ‘thingos’ that appear in parking areas and drag along the bottom of the car making a hell of a noise.

I’d recommend that you ask Kings (who manufacture in Brisvegas) to make you up a set that’s only 20mm lower. In other words 15mm longer than their normal lowered set. Kings have the same (within 2%) spring rate as the Eibachs. You should be able buy and have the Kings fitted for the same price of just the Eibach springs.

You don’t need to worry about a tower strut, the NC has one standard and the advertised alloy one is just bling.

Sways will make the biggest difference in the way your NC handles. It removes the roll (the lowered springs will also but not to the same extent) and improves quick directional changes but has a down side in that it increases understeer. Adjustable sways help dial this out as you can increase the stiffness in the rears to compensate for the fronts. This understeer really only shows up on the track so I wouldn’t worry about it too much for road use.

[Charlie Brown]

20mm also, as Garry eluded, puts you on the legal limit to get the required 100mm minimum clearance.

[DavidM]

I'm pretty sure that Kings sell 2 sets of sprins for NC, and one of them drops the car only about 2cm. Friend of mine has them on his NC and the drop is pretty subtle.

He got them (inlcuding fitting) for around $300 if I'm not mistaken.

[JBT]

Member of the Qld Mx-5 Club Club members get a discount at Fulcrum Suspensions.

[Mick93]

I wouldn't touch King Springs. I was told by many people on this forum when the socks went on my NA to get Konis and King springs. They are the worst spring. They are lower and harder but not progressive. Kings appear to only make cosmetic springs (make your car lower not better). I know I am going to get shouted down by heaps of people but I have been in motorsport for 17 years and have worked in motorcycle racing teams it is very hard to improve suspension you have to decide if giving up ride comfort for looks is worth it. Also there will be a performance loss if you just go for harder springs your car will skip more on uneven roads (read all roads). When my car had Kings it also needed the suspension more regularly inspected and tightened. I can't comment on Eibach springs but they do get a big rap in the US. I solved my problems with coilovers (Arigosta's) and they are awesome it is the best way of lowering your car and if you decide to sell your car whip them out and sell them on the forum they won't last long. The most you will loose is a grand and you will be able to set your car up to exactly to what you want, easily worth the cash

[DavidM]

Mick93, I can only comment on the small-drop King springs in the NC. The car has nothing but springs and compared to stock ...
1. It has better responsiveness.
2. It handles mid-corner bumps better. Stock car was a bit scarry sometimes while now the car takes these more in it's stride.
3. No noticable difference in ride quiality. The car is probably firmer, but it still rides over bumps more like a luxury car.
4. It looks only marginally lower than stock.

Also this particular car has no problems with pot-holes, driveways, etc. I also measured the lowest point on the car, and that was the rubbery mud-flap in front of the front wheels, which was still good 11cm+ above ground.

Not sure what other springs are like on the NC, but I don't see a problem with the Kings.

ps. The car I'm refering to is a hardtop.

[Charlie Brown]

Kings have come back to me with a quote for springs that drop 30mm, I called Fulcrums and they basically said that that is probably right. They never had anything that is lower than 30mm.

Anyway, Fulcrums suggested I measured my car, which aint a bad idea really. So I took a tape measure and measured the lowest part of my car which seems to be the front mud flaps and they were 135mm off the ground, so even 30mm would keep me okay I presume.

I think you will find that your NC is a lot lower than 135mm.
Mazda’s official ground clearance is 119mm. I’m sure that this is the cross member sitting under the engine and not the little plastic flaps in front of the tyres although there isn’t a lot of difference between the two.

Kings may have changed the NC spring drop from the ones initially developed with them for my car.
The original spec was to match as close as possible the Eibach/Mazdaspeed springs which were 35mm drop with a 28% increase in spring rate.

One point you need to remember is that the springs will settle. My first set dropped another 10mm after installation, making them 45mm lower than standard. Way too much. They wound a second front set a bit longer to start with and they settled 7mm.

Here’s a little comparison for you. Measuring from the centre of the wheel to the apex of the curve in the guard I had the following numbers;

Standard: Front 385mm, Rear 370mm
My initial King setup settled to: Front 335mm Rear 335mm
My current figures after fronts redone: Installed at 350mm settled to 343mm, Rears installed at 340mm now settled to 331mm.

So if Kings are now saying they only do a 30mm drop, then they have change them since I had mine installed 2 ½ years ago. If it settles to that figure (30mm) then they will be fine.

[DavidM]

Mine is a hard top too (does this make a difference?)

I think the hardtop has slighlty different suspension setup from the factory. Not sure if it makes any differene here though.

When you say low drop Kings do you know what exactly you bought? They said today they only have 30mm drop springs.

Yes, 30cm is what I think the claimed drop is. This is what is sais on the box KMFL-40SP ... probably the model number?

[Mick93]

The biggest problem I had with thing Kings were there inconsistency in manufacture. When we put the the springs in a \"shock dyno\" each leg was noticeably different the compression load was up to 20% different and the rebound of the spring was up to 30% I was told by my friend (who imports Ohlins and sets up most of the V8 supercars) that this was down to the tempering process of the spring. This makes it hard to set your shocks up and I had Koni adjustable sports. I know that Eibach say they test there spring I imagine to stop this sort of inconsistency. Without driving a NC with Kings I suppose it is hard to tell. I would imagine there are god Kings and bad ones Lou who has had about a million MX5's now also commented to me he tried a NA with Kings/Konis and said the same thing as I so maybe they have a better spring for the NC.

[Mr Morlock]

Mick93 sounds like a bloke who knows what he is talking about. The one thing that jumps out at me is that quality suppliers are ones that produce consistency and that only comes about through Quality systems and their application. The guy in the street often does not really know what he is buying. There are few suppliers around who possess the standards demanded by the OEM car makers. We often have to rely on guys like Mick to help out in the selection process.

[wun911]

Looks ok not scraping the tops of speed bumps are you?
With a small drop do you notice any diference around the corners?

[@ndrew]

Doesn't look lowered

Springs haven't settled yet...

[mx5racing]

you could go for the \"fully dropped\" look.



Handles great on a very smooth road......... other times its about as handy as a hip pocket in a pair of speedos.....