just fitted 18, s---handling issues --twitchy

rustynuts · Post by **rustynuts** » Wed 02 Dec, 2009 13:33

Hello all, just got my first Z a short time ago,and i love it, I decided to swap the standard 16" alloys for 18" e46 alloys, fitted a treat and look brilliant,but the handling has gone from bieng good to very nervous and twitchy, you now have to steer the car all the time,any advice , comments would be apprieciated, thanks

Gazza · Post by **Gazza** » Wed 02 Dec, 2009 13:49

It appears you are now getting 'Bump Steer' probably due to in increase in tyre width and wheel size. It would be worth getting the front alignment checked, that may improve your ride

Another thing

Check the centre bore size of the new wheels, that would also upset the ride if not centred on the hub correctly, if larger than the original wheels you will need to get some spigot rings

Welcome to the Forum

Dav · Post by **Dav** » Wed 02 Dec, 2009 14:41

A little more information would be helpful. What width are the wheels and tyres and what make of tyre have you got on the wheels.
Which wheels are they? Got any pics?
Gazza makes a good point about the bore (the centre hole of the wheel) which should be 72.6mm. Some BM wheels are 74.2mm whic means there is movement on the hub.

Mike Fishwick · Post by **Mike Fishwick** » Wed 02 Dec, 2009 16:07

What offset are your new wheels? This is the kind of thing which happens when people choose wheels for their cosmetic effect, without considering other factors.

Tyres are another factor, too - what type and size are you using?

chas 1 · Post by **chas 1** » Wed 02 Dec, 2009 16:07

I am no expert on techy stuff, but it sounds to me like you need to think safety above all. Your wheels may look good , but lying in a wrecked car twitching is not a good look.
Put your old wheels on, and remember there is a reason they were fitted in the first place.
The best handling (on normal roads) of the 3 Z3s I have driven was a 1.9 on bog standard wheels.

mv70 · Post by **mv70** » Wed 02 Dec, 2009 17:18

Tyre brand, model and/or wear can make a big diffrence as said before .

Hope you dont got cheap china tyres..

rustynuts · Post by **rustynuts** » Fri 04 Dec, 2009 15:26

Hi all thanks for the replies, s the wheels are i believe standard bmw wheels with wider rears, fitted with 225/40 and 255/35 goodyear eagle f1 tyres inflated to 30psi

Mike Fishwick · Post by **Mike Fishwick** » Fri 04 Dec, 2009 16:23

Yes yes - but just because they are BMW wheels, and were standard on an E46, does not mean that they are just the job for your Z3.

What offset do they have? This may be the key to the whole problem, but the additional lower profie will not help, and other factors have to be considered, such as the condition of the front wishbone rubber bushes, toe-in, and - probably to a lesser degree - the rear end bushes also.

You have to consider other factors than that they look pretty.

MarkOliver · Post by **MarkOliver** » Fri 04 Dec, 2009 16:34

as said check all wheels are correctly balanced and tracking is OK....18" wheels will feel quite different from 16" IF they are MV1s or MV2s they should be fine.

Are they new tyres ? they might need 500 miles orso to fully scrub them in.

rustynuts · Post by **rustynuts** » Fri 04 Dec, 2009 22:45

the more i look through the forum i think i may be experiencing "tramlining" which seems to be a feature on z,s with larger wheels,the polybush wishbone solution and getting the alignment checked seems to be the way to go,im going to order some powerflex bushings and give it a go,bearing in mind that my z is a high milage example,so the bushings are probably well past thier best

siwilson · Post by **siwilson** » Fri 04 Dec, 2009 22:53

How new are the tyres? If brand new then kaybe just need scrubbing in a little.

Does this happen on all road suraces or just some?

rustynuts · Post by **rustynuts** » Mon 07 Dec, 2009 10:09

siwilson wrote:How new are the tyres? If brand new then kaybe just need scrubbing in a little.

Does this happen on all road suraces or just some?

Hi, the tyres are worn as i bought them complete on the wheels,
the car seems fine on smooth A roads, but if an area has been repaired/patched it will tend to follow the ruts

gookah · Post by **gookah** » Mon 07 Dec, 2009 21:44

rustynuts wrote:the more i look through the forum i think i may be experiencing "tramlining" which seems to be a feature on z,s with larger wheels,the polybush wishbone solution and getting the alignment checked seems to be the way to go,im going to order some powerflex bushings and give it a go,bearing in mind that my z is a high milage example,so the bushings are probably well past thier best

forget polybushes it made my tramlining worse, only thing that cured it was getting rid of front Pirellis tyres, even with a mixed tyre set up - Avons front pirellis rear, it was cured.
I tried allsorts, wishbones, bushes, springs, It was the tyres,
My wheels are 18".
oh and spigot rings will correct concentricity issues not tramlining, If you have wrong size spigots you will feel vibration as the wheels may have been tightened off centre on the hub.

Canman · Post by **Canman** » Mon 07 Dec, 2009 21:58

there seems to be so many different opinions , explanations , cures for this problem. my experiance has been that i bought the car with 17" bmw style 67 mtec alloys on and fitted with cheap , nameless tyres all round 225/45/17 front 245/40/17 rear. no tramlining , nothing. great handleing. now got my 18's style 68 on with continental contisport . and tramlining in rutted/uneven roads.
not sure where to go, but going to go for poly bushes on front wishbones and then see what happens. had my car laser aligned too prior to new wheels.
at £30 poly bushes cheaper than tyre changes and might help with steering if it doesn't cure tramlining.
i

markrnorton · Post by **markrnorton** » Tue 08 Dec, 2009 07:36

I found the polybushes made a difference, tightened up the front of the car no end.

Z3 does seem to be sensitive to what tyres it wears !

Perhaps somebody should start a 'what tyres do and dont work' thread

gookah · Post by **gookah** » Tue 08 Dec, 2009 08:57

I fitted powerflex front-wishbone rear bushes to try and cure my tramlining at the suggestion of people on here and it just accentuated it, So much so that the change in direction was more violent. and also now the car is very crashy and harsh over bumps,
Still if you have the money, carry on,
Also the suggestion of 'you must have the same tyres all round' meant I would have changed my end of life front pirellis to match the rear pirellis with the same again, only to keep tramlining, but I went for Avons front and pirellis rear and it cured it,
There are a lot of sweeping statements that have to be taken with a pinch of salt,
Wait for the strut brace one, its overdue.

this is what I did to try and cure my tramlining,
2 new wishbone arms- no improvement
tyres pressures, up and down- no improvement
new springs all round -no improvement
powerflex bushes - worse
4 wheel alignment- no improvement
Mixed tyre set-up -Cured!!!!
Try not to waste over £300 like I did.

markrnorton · Post by **markrnorton** » Tue 08 Dec, 2009 09:29

Rustynuts

first and foremost, get the right wheels (correct offset etc) and a set of decent (all the same) tyres.

thats a good starting point. otherwise you will be trying to make good from bad, so to speak.

Someone start a thread on tyres !!!!!!

gookah · Post by **gookah** » Tue 08 Dec, 2009 13:36

markrnorton wrote:Rustynuts

and a set of decent (all the same) tyres.

!

see what I mean. "all the same tyres",

Glad I didn't listen. all the same was a tramlining nightmare on mine, I mixed them up and cured it,
they were the same wheels, same tyres and same sizes and pressures, Pirelli 6000's -Bloody lethal!!

Justin Time · Post by **Justin Time** » Tue 08 Dec, 2009 13:46

Gookah, have you tried any Goodyear, Toyo or Falken branded tyres? Forum members' experience with these brands is where the majority of the "all the same" comments come from.

I'm not trying to put down your point of view regarding your current setup, it's another alternative and one I do not have experience with, but classing every full set of tyres as being a nightmare when it comes to handling is not accurate. In fact, from my point of view, you could put it with all the other "sweeping statements that have to be taken with a pinch of salt".

chas 1 · Post by **chas 1** » Tue 08 Dec, 2009 14:35

In my limited experience Gookah and Justintime are sort of both right. It makes sense to have 4 tyres the same, but any pirelli 6000 , any where, front, back or all round, certainly make my Z3 a killer car from hell.
Bridgestones make it a complete pussycat.

Of course, if you are going to start putting what are effectively the wrong wheels on, (Big, Blingy, Expensive, non standard, showy), then on your own head be it. Oh and by the way, when you changed the wheels - or anything else on the car, you did inform your insurance company to keep it valid didn't you?

Jeez its your Dad talking isn't it......

markrnorton · Post by **markrnorton** » Tue 08 Dec, 2009 16:02

gookah

calm down man, anyone would think you knew it all

all of us are just passing on our experiences, not saying its right, wrong or otherwise.

I have had 3 sets of tyres on the Z, Dunlops, Avons and Kuhmo's. All matched and never had any real issues with tramlining.

if Z's were meant to have mixed tyres i think bmw would have spec'd it dont you ? (general comment to forum)

gookah, you have found a mixed set that works, good. However, Another nail in the Z's handling coffin.

The Z is a shocking parts bin special with a flexing chassis , when you couple this up with worn bushes, suspension parts and ball joints, everyone (car) will indeed be different and everyone may have a different solution to correct its ill handling traits

I have changed:-

front top mounts - now billet alloy rose jointed adjustable with neg camber
coilover set-up all round (running 350lbs springs)
new front wishbones
polybushed
new drop links
strutbrace
modified rear ARB
18" wheels with 225 tyres ALL round and all the same (gives great balance)
3mm spacers on front wheels

plus loads more modifications,

but, this set-up gives a car with very neutral handling, masses of grip , great turn in and no tramlining issues. I want it mainly for track days, however it is compliant on the road even though its aprox 55-60mm lower than standard

this is my experience, i dont expect others to agree or disagree (unless you have the same set-up and weight distribution or you have driven my car)

match the suspension and ride you want with the sort of wheels and tyres you intend to use.

Rustynuts - as you can see, its a hot topic with a million solutions

rustynuts · Post by **rustynuts** » Tue 08 Dec, 2009 19:35

WOW, thanks guys for all the comments, I seem to have opened a right can of worms !!! , maybe i should have stayed with my MX5 (only kidding)
Anyway ive swapped back to the original 16" wheels for now with cheepo tyres and ive got the handling back,
I,ll wait till springtime and have a play and see if i can sort it with the 18,s
I know its being a bit of a poser,but i love the styling with these wheels.

gookah · Post by **gookah** » Tue 08 Dec, 2009 19:58

Justin Time wrote: but classing every full set of tyres as being a nightmare when it comes to handling is not accurate. In fact, from my point of view, you could put it with all the other "sweeping statements that have to be taken with a pinch of salt".

I did not class every full set of tyres as a nightmare, If you read my post 'accurately' you would see that I said all the same tyres were a nightmare 'ON MINE', that is not sweeping, but accurate and it was because they were Pirelli's!
Many people on here always state that it is the only cure and I commented that if I had listened to them then all the same Pirellis, as I had, would have been the only option in replacement. and would have still left me tramlining.
so It was not a sweeping statetment like the one's I refer too. it is my experience, to try and put forward a real fix to help someone.
and I have also described what did and what did not work from experience, unlike a lot who only give opinions or hearsay.
stick 4 equally matched cross plies on, that must be better as long as they are all the same.
:

PS I dont know it all, ....just most of it

markrnorton · Post by **markrnorton** » Tue 08 Dec, 2009 20:38

That's ok then

Justin Time · Post by **Justin Time** » Tue 08 Dec, 2009 23:30

I stand corrected.

heng1028 · Post by **heng1028** » Wed 09 Dec, 2009 06:44

i have the exactly same problem.

i swtiched from the fatory 15s to 18s BBS RK original with Michelin PP2 tires all around (225/40/18). Did alignments and all.

The car handles very bumpy and no more grip on corners

any solution for this? i will swap the 15s back and see if it happens on 15s or not.

Robin · Post by **Robin** » Wed 09 Dec, 2009 08:02

When we bought a Volvo C70 convertible the dealer advised that the T5 version suffers more scuttle shake & bump shudder because of the lower profile tyres fitted to that version.
The larger wheels obviously means less rubber so a harder ride. Low profile tyres are probably best kept for the track rather than our bumpy road surfaces. Especially on convertibles.

zedder3 · Post by **zedder3** » Wed 09 Dec, 2009 08:08

Robin wrote:When we bought a Volvo C70 convertible the dealer advised that the T5 version suffers more scuttle shake & bump shudder because of the lower profile tyres fitted to that version.
The larger wheels obviously means less rubber so a harder ride. Low profile tyres are probably best kept for the track rather than our bumpy road surfaces. Especially on convertibles.

similarly, on a previous car I uprated the suspension and changed the wheels from 15" to 17" at the same time. the ride and handling were shockingly bad. changing the wheels back, so tyres with high profile were back on, made a big difference to this. maybe it's something you have to put up with if you want to increase wheel size on this car

Riwa · Post by **Riwa** » Mon 14 Dec, 2009 23:09

Try fitting a strut brace before giving up on your new rims and tires. Doesn't have to be a fancy one, just get one.
Thats all I'm sayin.

gookah · Post by **gookah** » Tue 15 Dec, 2009 19:04

gookah wrote: Wait for the strut brace one, its overdue.

and about time too

Riwa · Post by **Riwa** » Tue 15 Dec, 2009 21:05

Just beacause you have an opinion doesn't mean you're right.

gookah · Post by **gookah** » Wed 16 Dec, 2009 20:49

its just the right kind of opinion though

markrnorton · Post by **markrnorton** » Wed 16 Dec, 2009 21:24

I doubt it

gookah · Post by **gookah** » Thu 17 Dec, 2009 22:39

that's your opinion

Fender2004 · Post by **Fender2004** » Fri 18 Dec, 2009 10:55

I think I'll stick with my original wheels and tyres

as I've just got the steering spot on, so I don't want to mess it all up again by changing the wheels and tyres.

chas 1 · Post by **chas 1** » Sun 20 Dec, 2009 17:13

I, who know nothing, can see that very low profile tyres are closer to cart wheels , with iron rims, than the standard wheel and tyre as fitted by BMW.
Nice high spongy side walls are whats needed for our terrible roads, and if i had a pound for every one of my mates who has specked a new BMW or any other high end car with ultra big wheels with ultra low profile tyres, and bitterly regretted it , I would have £17.

Perhaps its time for functionality of wheels and tyres to come first, and not looks. Mind you, I am very very old....
But don't get me started on Pirelli 6000 killer tyres from hell.

zroadster.net

just fitted 18, s---handling issues --twitchy

just fitted 18, s---handling issues --twitchy

Offset

think safety

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