mx5 na uneven stance

Discussions relating to MX5 Tyre choice, Wheels, Brakes Suspension components and other items to keep you going around corners, stuck to the ground or stopping on a dime.

Moderators: Growler, jif, Born_disturbed, punkoutnz

Post Reply
bungfoot
Hey. They are NOT Training wheels.
Hey.  They are NOT Training wheels.
Posts: 2
Joined: Sat Dec 12, 2015 7:34 pm

mx5 na uneven stance

Post by bungfoot » Sat Dec 12, 2015 8:07 pm

hi im new here and am trying to fimiliarise myself with my new toy ! first issue to deal with is that the car sits higher on the passanger side by about 15 mm on the rear and 5mm on the front.i have changed struts from side to side and still the same.also replaced with new springs no change.all bushes tight with no play or clunks. has anyone got any ideas? running standard shocks and king springs . cheers

evel
I have stars and not afraid to use them
I have stars and not afraid to use them
Posts: 227
Joined: Tue Dec 13, 2011 9:19 pm
Location: Whenuapai, Auckland

Post by evel » Sat Dec 12, 2015 9:52 pm

Give the springs a few weeks to settle in.
I take it you have measured the heights? I always feel like i'm lower on the drivers side but I proved myself wrong once I measured the sill heights.
Did you notice if any of your control arms are abit bent?
'94 S-Special 1800 in BLACK
Flares and 225/45 Semi Slicks.

bungfoot
Hey. They are NOT Training wheels.
Hey.  They are NOT Training wheels.
Posts: 2
Joined: Sat Dec 12, 2015 7:34 pm

Post by bungfoot » Sun Dec 13, 2015 8:21 am

thanks for the input. yes I have checked the heights and pasanger side is 15 mm higher when measuring the sil also. have read that the camber adjustment can alter height by as much as 20 mm .as I haven't done this yet that may be the cause.

Wrangler
Hey. They are NOT Training wheels.
Hey.  They are NOT Training wheels.
Posts: 5
Joined: Wed Mar 30, 2016 10:36 am
Location: Christchurch

Post by Wrangler » Wed Mar 30, 2016 10:45 am

I have the same issue, when I had a wheel alignment a couple of weeks ago when I had new rear tyres fitted the said that the front right was 20 mm lower then the left.

So I checked myself and measured from the ground to the fender, through the centreline of the wheels, with the following results.

Front Right 600 mm
Front Left 615 mm

Rear Right 625 mm
Rear Left 640 mm

Where do I start looking to fix this? Is it likely the the springs are starting to get tired at 220,000 km? Or should I be looking at control arm bushings etc, as I am not sure how long these last either?
1992 1.6L NA Automatic

marcellarius
I count 5-s in my sleep
I count 5-s in my sleep
Posts: 367
Joined: Thu Apr 18, 2013 12:52 pm
Location: Hamiltron

Post by marcellarius » Wed Mar 30, 2016 11:39 am

Normal.

The corner weights aren't equal -- the front right is the heaviest and will sit lowest, this will tend to lift the diagonal opposite a little. The solution is corner balancing, which involves fine-tuning the ride height at each corner so that each diagonal carries an equal share of the weight. This requires adjustable struts and scales.

Wrangler
Hey. They are NOT Training wheels.
Hey.  They are NOT Training wheels.
Posts: 5
Joined: Wed Mar 30, 2016 10:36 am
Location: Christchurch

Post by Wrangler » Wed Mar 30, 2016 4:07 pm

Interesting to note that this is "normal".

One of the issues that I though this may solve is that, during the wheel alignment, the caster on the left hand side was able to be set to the spec of 5 degrees, but the right hand side was set to 4 degrees. I assumed that would be due to the lower height of the right hand side?

Is there any way, without adjustable struts, which would need certification, that I can level things out? Can I add some sort of trim packer or thicker spring mount?
1992 1.6L NA Automatic

siren676
I have stars, you haven't. Deal with it
I have stars, you haven't.  Deal with it
Posts: 1115
Joined: Fri Jun 08, 2012 12:21 am
Location: Auckland

Post by siren676 » Wed Mar 30, 2016 4:27 pm

Is it on standard springs and shocks? Sounds like the right front has sagged over the years.

Also just re-reading your post, the most accurate measurement is center of hub to the arch not hub to ground as tyre pressures can effect that measurement
1990 NA6C MX5

Wrangler
Hey. They are NOT Training wheels.
Hey.  They are NOT Training wheels.
Posts: 5
Joined: Wed Mar 30, 2016 10:36 am
Location: Christchurch

Post by Wrangler » Thu Apr 07, 2016 3:51 pm

Hi There,

I have checked the tyre pressures and they are all good, and remeasured from the underside of the flare to the top of the recess in the wheel for the cap that goes over the wheel nuts and the measurements are still out of wack, so I guess I am looking at new springs.

From ringing around I have found two places that do stock height springs, as well as lowering ones, but neither have replied to me on spring rates, so anyone have any advice or used the following?

- Tein Springs Spring rate F 235 lbs/in - R 168 lbs/in
- Cobra Springs
- Dobi Springs

From other searches, I have found that an Auto MX-5 should have the white dot front springs, which I do, rated a 165 lbs/in ,and 95 lbs/in rear.
1992 1.6L NA Automatic

marcellarius
I count 5-s in my sleep
I count 5-s in my sleep
Posts: 367
Joined: Thu Apr 18, 2013 12:52 pm
Location: Hamiltron

Post by marcellarius » Thu Apr 07, 2016 5:12 pm

As I said before, it's because each corner doesn't weigh the same amount. If my memory serves the front drivers side is something like 50kg heavier (steering column, instruments, pedal box and brake booster, plus all the crap on that side of the engine bay).

I noted the exact same thing when installing adjustable suspension in my car. I wouldn't stress about it unless you're just looking for an excuse to replace your springs ;)

Wrangler
Hey. They are NOT Training wheels.
Hey.  They are NOT Training wheels.
Posts: 5
Joined: Wed Mar 30, 2016 10:36 am
Location: Christchurch

Post by Wrangler » Thu Apr 21, 2016 5:25 pm

Hi There,

While not really wanting to replace my springs, especially since most manufacturers will not give out spring rates, I find it hard to believe that Mazda would let the car leave the factory all leaned down on one side?

I can understand that the weights may be different, but figure that they would have allowed for that when they designed the car. I guess that now I know that it is not right, I have an OCD desire to fix it :lol:

I have just replaced the rear tyres and one wore more than the other, so figure this may have contributed to that and do not want the same thing to happen again. It could have also been that the alignment was a victim of the Christchurch roads :)
1992 1.6L NA Automatic

marcellarius
I count 5-s in my sleep
I count 5-s in my sleep
Posts: 367
Joined: Thu Apr 18, 2013 12:52 pm
Location: Hamiltron

Post by marcellarius » Fri Apr 22, 2016 3:57 pm

It's as designed. The factory suspension setup is very soft with a lot of preload. and the slight imbalance doesn't really affect handling on that setup.

Stiffer springs will reduce the magnitude of the effect, but even with springs twice as stiff as factory on evenly adjusted coilovers you will still see a height difference.

Keith Jones
I count 5-s in my sleep
I count 5-s in my sleep
Posts: 329
Joined: Thu Jul 06, 2006 6:30 pm
Location: Waiuku

Post by Keith Jones » Fri Apr 22, 2016 7:11 pm

In support of marcellarius' comments. Some years ago Donovan measured the corner weights of his NA before putting in the V8. The results were LF 240kg, RF 264 kg, LR 240=1kg, RR 240 kg.
The OEM front spring rates are 163lb/in (manual transmission), so the 24kg right to left weight difference will make the driver's side around 8mm lower than the passengers at the front.
As marcellarius said, the only way to even up the heights is to use adjustable perch coilovers, but these are intend for equalising corner weights, not heights.

WideOpenThrottle
I have stars, you haven't. Deal with it
I have stars, you haven't.  Deal with it
Posts: 1293
Joined: Wed Dec 24, 2008 11:35 am
Location: 36.8167° S, 174.4167° E

Post by WideOpenThrottle » Sat Apr 23, 2016 8:32 am

In my one-off experience of trying to do the same with an Audi that was different heights at each corner, all I ended up doing was chasing my tail as each time you altered the height of one corner it affected all the others so I was never able to even them up. I put it down to the body being a rigid structure so each corner is going to move at the same time by varying amounts!
Learn to live with it :D
1989 NA 1650
1998 NB 1800
2005 NC 2000
1990 Landcruiser
Surfboard
Push-bike
Hiking shoes

Timmo
I count 5-s in my sleep
I count 5-s in my sleep
Posts: 393
Joined: Mon Sep 07, 2009 1:08 pm
Location: Takanini

Post by Timmo » Sun Apr 24, 2016 3:14 pm

here's a related question- Why would the upper mount bolts have different amounts of thread showing above the nuts between left front and right front when fully tightened?
I've just installed a standard NB front tower brace on my NA, on the drivers side when done up, there is still 3-4 rows of thread left above the nuts. On the passenger side however, even when done up to the same torque, the end of the thread is flush with the top of the nuts?...which makes me nervous as, due to the taper of the bolt, the nut isn't fully sitting on the thread.
Ex: 1991 BRG NA6, 1998 White RS, 1997 Wine Merlot M Edition

Keith Jones
I count 5-s in my sleep
I count 5-s in my sleep
Posts: 329
Joined: Thu Jul 06, 2006 6:30 pm
Location: Waiuku

Post by Keith Jones » Tue Apr 26, 2016 10:00 am

It sounds like one of the top hats has been changed at some time. With my current NA, the thickness of a brace would result in the nuts only just reaching the top of the threads, whereas on my old NA, which did have a brace fitted for a short while until I realised it wasn't doing anything, there was plenty of thread showing. It looks like Mazda made top hats with different length studs.

marcellarius
I count 5-s in my sleep
I count 5-s in my sleep
Posts: 367
Joined: Thu Apr 18, 2013 12:52 pm
Location: Hamiltron

Post by marcellarius » Tue Apr 26, 2016 4:47 pm

Keith Jones wrote:In support of marcellarius' comments. Some years ago Donovan measured the corner weights of his NA before putting in the V8. The results were LF 240kg, RF 264 kg, LR 240=1kg, RR 240 kg.
The OEM front spring rates are 163lb/in (manual transmission), so the 24kg right to left weight difference will make the driver's side around 8mm lower than the passengers at the front.
Closer to 12mm once you account for motion ratios.

As the spring/strut is mounted inboard, the lower control arm acts as a lever increasing the force on the spring (or conversely, decreasing the effective spring rate at the wheel).

Image

Post Reply

Return to “MX5 Suspension, Wheels, Tyres & Brakes etc”

Who is online

Users browsing this forum: No registered users and 12 guests