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Hi all,

since moving down South, my little car has been copping a hammering from the goat tracks they call roads. The Koo Wee Rup road and the South Gippy hwy in particular are in such poor states that there is now a an extensive set of signs recommending an 80k limit. Since the holiday season started I've noticed a lot of smashed stanchions on the biker-dicer cable roadside furniture - often in places where a road undulation might well have contributed to loss of control.

Anyways, to cut a short story long, I'm wondering what, if any, suspension options exist that will give me a better ride - kinder to kidneys and car - without hurting the handling.

Thoughts?

Better ride than what?
What do you have on there now?

If it's stock springs/shocks I'd suggest first of all replacing the shocks, the original ones are probably quite worn if they've been on there for 20 odd years.
Stock suspension in good condition is about as comfortable as you can get in an MX5 without doing things like rasing the suspension etc.

Buy a Corolla.

hks_kansei wrote:Better ride than what?
What do you have on there now?

Standard stuff HKS.

hks_kansei wrote:If it's stock springs/shocks I'd suggest first of all replacing the shocks, the original ones are probably quite worn if they've been on there for 20 odd years.
Stock suspension in good condition is about as comfortable as you can get in an MX5 without doing things like raising the suspension etc.

Thought the damping would suffer first and the ride would get softer! Hear what you're saying though, probably well overdue to have them looked at.

project.r.racing wrote:Buy a Corolla.

Thought of that. i30 from Hyundai or Suzi Swift. Just to commute in you understand. My loyalty to the 5 is permanent.

Shocks with little to no damping will be softer, but will also feel worse.

The springs will be uncontrolled and can make the car sway and bounce, which feels less comfortable.

Buy some suspension that is properly setup and correctly valved. 1k coilovers won't do the trick... KW, Ohlins etc will... but you'll have to spend proper money.

Having separate high speed valving makes a massive difference on big bumps and pop holes.

I've got KW competitions, I more than doubled the spring rates compared to my old setup, yet the ride quality is better. Over big bumps there is no comparison at all with OEM or normal coilovers. Their road optimised V3s would probably be ideal. Otherwise maybe Ohlins? Bilstein PPS9s are okay but old tech and no high speed valving. But you can get them for almost half the price of V3s and 1/3 the price of Ohlins.

To a certain extant you have conflicting needs for softness and grip. Bounce frequency is the rate at which undamped wheels naturally oscillate. It reflects the speed at which wheels are able to move up and down over bumps. Higher bounce frequencies give better/longer contact over bumps and hence more grip. Soft springs give low bounce frequencies. Hard springs give higher bounce frequencies.

If you just want more comfort then get new/better shocks, but you'll still find the car being thrown by sharp bumps and corrugations. If your priority is for more grip over crap roads then get stiffer springs and better shocks.

Standard springs are rated at 2.9/1.8 Kg/mm front/rear. I found that going to 5/4 on high spec Teins made my car much more comfortable, especially on rough roads, and it stuck better. Stiffness is very subjective. I feel that anything up to 7/5 is reasonably comfortable for country driving but 7 and up is a bit too hard on the spine for low-speed city driving - you'll feel every crack and tram track.

Thanks chaps, must think about this some more. So it's a typical 2nd order system with mass, spring and damper, slightly underdamped I'm guessing from what Manga says. Then as the damping action degrades over time, the wheel will "patter" which is likely to feel harsher than if it were dampened more - is that right?

I've reserves for "1k coilovers" Ben but this looks like false economy. Sounds like it's better to save up and put up with it in the interim.

And Dave don't forget the OEM rear shocker bump stops won't be helping, as by now you'll probably be running very close to them a lot of the time.

So something like these are within the budget:
http://www.mx5mania.com.au/product1708.htm
or these:
http://www.mx5mania.com.au/product646.htm
added to these:
http://www.mx5mania.com.au/product698.htm
Simply cannot afford these:
http://www.mx5mania.com.au/product1053.htm
Is there a better place to shop or are these prices typical?

Unless you want to lower the car I'd suggest keeping the standard springs.

Lowered springs won't help the ride quality.
I have similar Eibach springs on mine (mine are the Mazdaspeed ones, which if I recall aren't as low as the pro-kit, and have a slightly different rate)
The ride is very close to stock except on hard compression where the rear will sometimes hit the bump stop.

Replace it with new or buy expensive units if you want ride comfort and control.

It really is that simple.

Cheap coilovers are not the ticket.

Dann

hks_kansei wrote:Unless you want to lower the car I'd suggest keeping the standard springs.

Cheers HKS, didn't realise the Eibachs were shorter.

NitroDann wrote:Replace it with new or buy expensive units if you want ride comfort and control. It really is that simple. Cheap coilovers are not the ticket.

Thanks Dann. I think the message is beginning to sink in.

- Smaller diameter wheels to allow for higher profile tyres (will be difficult if your mx5 has the stock 14's)
- A softer seat ie. sheep skin seat covers or even a cushion for extra padding (if you don't mind compromising the driving position and you aren't tall)

MCA gold series coil overs will solve your problems. They are custom build so you can get them to suit your driving/ roads and ride height.

If they can keep the rally boys happy and win world time attack challenge I'm sure a bit of rough highway will be no problem.


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