Poor handling after a service

[cemilbrowne]

Hi all, I'm having a weird problem that I'm struggling to diagnose, and I'm hoping someone might have some ideas.

I have a 2006 NC unmodified. Car was absolutely fine. Had my 6 month service due - took it into the dealer (not Mazda, long story), they did the usual service, incl rotating the tires.

I got back into the car and immediately noticed that the alignment was now WAAAY off. The car pulled badly to the right on acceleration and came back on deceleration. I took it back to the dealer, they played with it and gave it back. Said the rotation was an issue. My guess is that they mismatched tires, or something along those lines.

Anyway, when I got it back, it was significantly better. The car no longer severely pulled to the right on acceleration, but it still was acting - for want of a better word - squirrelly. Whereas before, I could just trust the car on curves or serious acceleration, it now felt - wrong. For example:

• The traction control light seems to come up far more often when cornering now.
• Occasionally the car "skips" if I brake quickly when cornering.
• The car sometimes "clunks" if I brake when cornering.
• It feels like the back end fishtails slightly if I downshift hard.
• It feels like the back end can fishtail sometimes on corners.

I know this is not a very specific list, but it's hard to describe - the car just doesn't feel "right". I have no confidence that I'm not going to lose it on a corner or a bump, and that's really disconcerting.

Any ideas from anyone? Following the second dealer check-in, I went and got it aligned at Spinning Wheels, and it is perfectly aligned - I can go for 100s of meters without touching it, but then every now and then I'll accelerate and it'll pull to one side or the other. Very hard to describe.

Please - any help would be much appreciated. The tires "seem" fine, I've checked the pressure, etc. I'm just about at my wits end! The car handles like a Barina right now...

-Cemil

[NitroDann]

Buggered alignment wobble bolts?

You really need to give it to someone who really knows MX5's and let them drive it.

Dann

[cemilbrowne]

Any recommendations?

I'm in the lower North Shore - Sydney - for reference. I'm just tired of taking it back to the dealer, and I know they're just going to say "it's fine".

Also, doesn't it seem odd that it was fine before the service and then borked after? I mean, I can't imagine they did too much to the suspension?

Thanks,
Cemil

[NitroDann]

You just have to find someone who you are confident cares.

I have had cars brought to me which have been to all of the well known MX5 and suspension places in Sydney, only to find that the suspension alignment bolts were so buggered the washers has dished visibly. It literally only took a quick drive and kneeling down to figure it out.

The issue is getting someone to care.

If you require me to make a suggestion PM me.

Dann

[cemilbrowne]

You just have to find someone who you are confident cares.

I have had cars brought to me which have been to all of the well known MX5 and suspension places in Sydney, only to find that the suspension alignment bolts were so buggered the washers has dished visibly. It literally only took a quick drive and kneeling down to figure it out.

The issue is getting someone to care.

If you require me to make a suggestion PM me.

Dann

Hi Dann,

PM sent - thanks for the help.

-Cemil

[davekmoore]

I know you'll already have checked, but just to eliminate one possibility, are your tyres directional and still all facing the right direction?

[cemilbrowne]

I have and they are - and they're now matched (front and back). Same size, but the back ones are 'Z' rated, the front ones aren't.

Thanks for the suggestion - I suspect that they switched those around the first time.

Thanks,
Cemil

[project.r.racing]

my guess is that 1 or more tyres had miss matched tyre pressures. the symptons of shifting alignment upon accelleration and decelleration support this.

[JBT]

High tyre pressures can cause it to skip about on rough surfaces. Try setting 30-32psi cold.

[Charlie Brown]

My guess is that it’s uneven tyre wear across the tread.
When the tyres were rotated, the wear (from the camber) would have been difference between the original fronts and rears.
Until they "wear in" the tyres can feel skittish. When you took it back to them all they would have done would have been put the fronts on the rear and the rears back on the front.

If you have had it to Stu at Spinning Wheel, the alignment is fine as will be the alignment bolts and washers. Stu has been doing my NC for the last 7 years and knows his stuff.

Answers to your other queries:
• The traction control light seems to come up far more often when cornering now. See initial answer above.

• Occasionally the car "skips" if I brake quickly when cornering. Do your braking before the corner.

• The car sometimes "clunks" if I brake when cornering. Did they do a pad change at service?

• It feels like the back end fishtails slightly if I downshift hard. Do you match revs when changing down?

• It feels like the back end can fishtail sometimes on corners. See initial answer above.

[hks_kansei]

How low are the tyres on tread?

As tyres wear down they reach a point where the grip is reduced, and on tyres I've had, I've found they can also get skittish. (that's why racing slicks aren't just bald road tyres)

It may just be that one pair are worn a bit further than the other, and now the worn pair are at the front (likely) and you can feel it more.


You know the alignment is right, so I'd just check the tyres, see if they're worn down, and then check the pressures.

[cemilbrowne]

Thanks all - I'll double check the tires. It's just so frustrating having had it in the shop a few times now. Just want the car working properly. :-)

[cemilbrowne]

Hi all,

An update here - the tires "look" OK to me - I've checked them all - correct rotational direction, look to be wearing evenly without any visible problems.

Also, I did a test yesterday. On a dry, smooth road, I made a sweeping turn, and the car skipped through the turn - I could actually feel it slip slightly, repeatedly, and the traction control light came on.

Specifically, for those who know North Sydney, I was coming down Berry St to turn down Arthur St to enter the freeway southbound. That is a fairly sweeping turn from Berry to Arthur, and a good road. I would expect the tires to be "grippier" than what I experienced, at a reasonably low speed - and they used to be.

Does this provide another data point for any of you gurus out there?

Thanks,
Cemil

[Charlie Brown]

OK, a short tyre summary and please correct me if it’s wrong.

* They are mis-matched front to rear only by speed rating. (you haven’t said if they are the same brand, pattern or size)
* The tyres “look good” and I'm assuming you have checked the pressures as a number of people have said to do.
* The tyres skip/loose traction/are skittish when cornering at slow speed but you don’t say how fast you are going. If the rated corner speed is say 60kph are you doing 60, 80, 100, 120 when this happens?

How old are the tyres? Check the date stamp on the side wall in the elongated oval. There will be four numbers. The first two numbers will range from 01 to 52, the second two numbers from 06 to 13 and look like 2310 or 4107 or similar.

If the second two numbers are 06, 07, 08 or 09, then your tyres are too old and have gone hard which explains the lack of grip.

[cemilbrowne]

OK, a short tyre summary and please correct me if it’s wrong.

* They are mis-matched front to rear only by speed rating. (you haven’t said if they are the same brand, pattern or size)
* The tyres “look good” and I'm assuming you have checked the pressures as a number of people have said to do.
* The tyres skip/loose traction/are skittish when cornering at slow speed but you don’t say how fast you are going. If the rated corner speed is say 60kph are you doing 60, 80, 100, 120 when this happens?

How old are the tyres? Check the date stamp on the side wall in the elongated oval. There will be four numbers. The first two numbers will range from 01 to 52, the second two numbers from 06 to 13 and look like 2310 or 4107 or similar.

If the second two numbers are 06, 07, 08 or 09, then your tyres are too old and have gone hard which explains the lack of grip.

Hi Charlie Brown,

Will do - to answer what I can right now:

1) Don't have the tires in front of me, but from memory, same size different pattern, same brand.
2) I've checked the pressures.
3) From the Google Sat view, I can see that the corner I'm referring to above is a 40 kph corner. I was probably doing 60 (max). It certainly didn't "feel" very fast, considering I've taken the car on some very windy roads in the past and pushed it hard and never experienced this kind of issue.

I will check the date stamp. Thanks for the heads up.

Thanks,
Cemil Browne.