Severe Understeer

[MrNutter]

I mean scary understeer. Very very scary. In the wet I have to crawl around roundabouts etc so slowly that I'm holding up traffic yet I can feel the front end loosing grip. It's not too bad in the dry but is still there if I push it into a tight turn under braking. The wheel alignment is good, all the suspension components & bushes are good, tyres are only Supercats because that's all I could get in the 185/75-14 size I needed but they are 3/4 tread.

I know I'm in for a good tax return this year so I'm wanting to try to fix this understeer problem. Will be swapping the 14" wheels for a set of 15" but that won't (or shouldn't) help with the understeer. Any thoughts on what I might be able to do about it?

Thanks for any replies.

[Krisp]

the almighty cheese cutters . half your reason, supercats part of your reason and how is the wheel alignment?

[Boonz]

for a start, 185/75/14's are the wrong size for a commodore, they are too small in rolling diameter.
theres plenty of 205/65/15 inch tyres on rims floating round at wrecking yards or online, best get yourself a set of them and see how you go...

[MrNutter]

Wheel alignment is spot on & only done about a month ago. The Supercraps don't help but they are not a whole lot worse (understeer wise) than the Pirelli P400's I had on it before them, so I don't think I can really hold them responsible. I have heard something about swapping to a thicker? swaybar helping with the understeer but have no idea if that is true or not. It's an '88 series one if that makes any difference, one of the first VN's to roll off the line.

Boonz: The 185/75-14 was what the VN came out with standard when they first started making it. I think they went up to a 15" rim late '89. I am planning on whacking a set of 15's on it in the near future though along with a set of kings lowering springs & some Koni shocks but the increased wheel diamter isn't going to change the understeer part. The springs & shocks might have an effect but the wheel diameter won't, we already bolted on my mate's 15" wheels with good tyres, gave it a wheel alignment & gave it a try, was still no good.

[Boonz]

doesnt make a difference when it was built as to tyre size... im very doubtful that the load rating on that size tyre is correct for the weight of a commodore anyway

[Krisp]

are any of the bushes in the front original bushes?

[Krisp]

doesnt make a difference when it was built as to tyre size... im very doubtful that the load rating on that size tyre is correct for the weight of a commodore anyway

that tyre size and width is what the 88 came out with from factory as per place card

[MrNutter]

No the bushes have all (including inner control arms) been replaced with nolathane a year or so ago & they are all in good condition. Nothings been knocked out of whack or damaged that I can see.

EDIT: the understeer was there just as bad before the bushes were replaced. That was part of the reason for the front end rebuild along with shot inner control arm bushes. Struts are true, no bends.

[Boonz]

whats your wheel alignment specs if you have them recorded still?

[Krisp]

and the strut tops? i have massive understeer on my vn. all the bushes are new but the adjustable tops are so far out of whack. just reading the manual , does the car pull more to the left or right and is there any movement in the steering when stationary

[m1lky]

What pressure are you running in them?

Do you have factory springs or is it lowered?

[MrNutter]

Couldn't tell you the alignment numbers but I do remember the guy telling me & I remember thinking that they were spot on. I'll see if I've got a record of it anywhere later. Strut tops, maybe, I havn't checked them. It pulls slightly left but not too badly, can leave my hands off the wheel for a good couple hundred meters before I have to put them back on. If it was pulling badly I would have gone straight back to the aligners. No play in the steering wheel at all.

Tyres run at 32psi (my own gauge & accurate). Factory springs.

[Boonz]

might pay to have an alignment and camber check done... cos it sounds like you've got too much toe in and and not enough camber

[Brett_jjj]

Definitely get more camber dialled into it,that will help it turn in.The FE2 suspension equipped cars run up to minus 1 degree +/- 30 min of camber.

[92 VP SS]

I definiatly think that tyre and wheel combo are to blame. If pirelli p400s are as bad as p6000s I wouldnt use that as a benchmark I would think supercats are probably just as bad. Get a set of 15 x 7" rims with 205 55 / 60s . I just sold a set with good tyres for 200. Holden wreckers have heaps of them too.

[Darcon666]

All good suggestions however no matter what you change/do, it won't help if you have a structural/geometric problem with the front end... any chance the vehicle been in an accident?

Just a thought....

[Morton]

Upload some pics of your front end if you can Various suspension components, strut tops, wheels, and then a couple of full-face shots of the car from ground level.

[MrNutter]

Sorry it took me so long to get back to this.

No the car hasn't been in any major accidents & there's no sign that it has ever been. Can't get photos unfortunately, my camera is buggered.

I'm going to get a set of 15" wheels & some standard 205/65-15 tyres to go on it, get a wheel alignment & see how much of a difference that makes. This part is going to sound really stupid coming from an ex-tyre fitter but what other models 15" steel wheels will bolt straight onto the VN Series 1? You will have to excuse me, it's been over 10yrs since I was a tyre fitter & I can't remember what models suit.

[ucwepn]

any commodore wheels will fit except VE, try and get alloys if you can they will handle slightly better, when you get the alignment tell them about your handling problem they can advise you what is F***ed and needs replacing or whatever is wrong with it.