Suspension issue on QP? Worrying shimmy on uneven surfaces.

MarkMas

Chief pedant
Messages
8,795
My QP has started to make a worrying sideways shimmy or jerk when I cross over a change of road surface at speed. Basically if I cross a raised white line or just a longitudinal change of tarmac quality (I live in Gloucestershire!) at speed, the back end seems to leap a few inches from one side to the other. Not too violent, but noticeably unstable. I've only started noticing it in the last couple of weeks. Do we think this is a suspension thing, or a tyre thing, or what?
 

safrane

Member
Messages
16,747
Simple checks first;
Tyre pressures
Wheel nuts
Then up on a jack to see if there is any lateral play in the wheel by giving it a dam good tugging in 12/6 3/9 o'clock
 

Keano

Member
Messages
287
I had this on mine - what i described as a fishtail experience and not nice - Rear Shock Absorbers
 

Wack61

Member
Messages
8,764
My 4200 was like that with low odd tyres on front and rear, drove it to costco on the M6 all over the place in the tyre ruts , had 4 new Pilot Sport 4 tyres fitted and it was a different car , if the tyres are low I'd get them looked at first
 

CatmanV2

Member
Messages
48,543
My 4200 was like that with low odd tyres on front and rear, drove it to costco on the M6 all over the place in the tyre ruts , had 4 new Pilot Sport 4 tyres fitted and it was a different car , if the tyres are low I'd get them looked at first

*cough*

It bloody wasn't! Falken 452s all round!

C
 

Wack61

Member
Messages
8,764
*cough*

It bloody wasn't! Falken 452s all round!

C

Must have got it confused with one of the other cars , it was ok when I picked it up but within a few weeks it was all over the place when they got low , PS4s transformed it, I've never known such a transformation just down to tyres.
 

CatmanV2

Member
Messages
48,543
Must have got it confused with one of the other cars , it was ok when I picked it up but within a few weeks it was all over the place when they got low , PS4s transformed it, I've never known such a transformation just down to tyres.

I absolutely remember you having tramlining issues. But totally know it didn't have mismatched tyres :)

C
 

Wack61

Member
Messages
8,764
sorry if you've taken that as a personal insult and a stain on your character :D , I remember it having falkens on the back, for some reason I thought the front tyres were different , anyway the good news is the new tyres cured it instantly.

This MX5 has falkens on the front and some budget **** on the back and you can tell, it's a bit twitchy when you start pushing through bends so I'm going to put a set of Michelin Super Sports on it
 

Wack61

Member
Messages
8,764
Still pending unfortunately,work and house decoration is getting in the way, about 3 years ago I gave up driving for a living , then got bored, bought a small van, did a bit more , hated it and realised I wasn't making any money so wound it down, then a guy I used to work with who knew I used to run a transit pickup rang me up

You're not looking for a transit pickup are you

No

Only they're getting rid of one at work

No but go on then what is it

XLWB 2011 with 8K worth of service history

No I don't want it

OK, they only want £1200 for it

I'll have it :D

since then I'm sort of back in a job I thought was over, so work and decorating etc are getting in the way, If it was taxed and insured I'd take it somewhere to let them do it.
 

Wack61

Member
Messages
8,764
This MX5 has falkens on the front and some budget **** on the back and you can tell, it's a bit twitchy when you start pushing through bends so I'm going to put a set of Michelin Super Sports on it

If anyone is looking for tyres I can recommend YOKOHAMA ADVAN NEOVA AD08R , they get consistently good reviews, just put 4 on my MX5 and the grip is unbelievable, they really give me confidence even today when it was lashing it down it didn't let go like it did with the cheap **** on

I got them from a guy on ebay, took him a week to get 4

http://www.ebay.co.uk/itm/2-x-BRAND...R-205-45-17-TYRES-ad08-r-track-/192251749428?

He's in slough , did me 4 205/45/17 for £340 + £40 post
 

Contigo

Sponsor
Messages
18,376
Cheers Darren that's useful was looking to replace the "Debica" ditchfinders which are on the mx5 since I've had it (were brand new!) so will look at the Yokohama's I assume they are fine for mk1's too. Alot of the drift boys use Kumho's and Toyo R888's on the NA cars.
 

Wack61

Member
Messages
8,764
It is a slightly firmer ride as they have stiffer sidewalls but mine is lowered to speed bump scraping levels which is something I may have to look at

When I googled them I couldn't find a bad review
 

MarkMas

Chief pedant
Messages
8,795
Aspect Ratio

Well it turns out that I had 285/40R19 on the back (from when I bought it) while the spec says they should be 285/35R19. That's over an inch greater circumference, apparently, but I'm not sure that would be enough to make a handling difference, would it? It might, however, explain why my speedo reads the same as my GPS speedo, rather than under-reading as I would expect (I think).

I need new tyres so will replace these with 285/35R19 per-spec Pzero Rossos, which seem to still be available.

Annoyingly, last year I bought winter tyres to match what was on the car, rather than checking the spec sheets, so now I have 285/40R19 Sottozeros for the winter, which I need to live with or replace in the autumn.

Does aspect ratio matter much?

Tyre Aspect Ratio.jpg
 

Wack61

Member
Messages
8,764
Aspect Ratio

Well it turns out that I had 285/40R19 on the back (from when I bought it) while the spec says they should be 285/35R19. That's over an inch greater circumference, apparently, but I'm not sure that would be enough to make a handling difference, would it? It might, however, explain why my speedo reads the same as my GPS speedo, rather than under-reading as I would expect (I think).

I need new tyres so will replace these with 285/35R19 per-spec Pzero Rossos, which seem to still be available.

Annoyingly, last year I bought winter tyres to match what was on the car, rather than checking the spec sheets, so now I have 285/40R19 Sottozeros for the winter, which I need to live with or replace in the autumn.

Does aspect ratio matter much?

View attachment 44713

I don't think I've ever read a good word about Pirelli tyres on Maserati's , the latest version of the Michelin pilot sport 4 is the PS4-S which is being squarely aimed at performance car drivers as they're only making it in 19" and above for now, reviews are very good, if they're an improvement on the PS4 I put on my 4200 they must be very good.