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I am running my 1997 Saab 2.3ltr model 900 Convertible, on the following tyres.
n/s 2 x Ventus Sport K104 size 225/45 zr 17 94y.
o/s 2 x Marshall power racer size 225/45 zr 17 91w.
My pressures are currentley at 32psi all round but I am not happy with the very hard ride/"feeling like hitting tramlines",
Can you give me guidance on what pressures to run??

Many Thanks
Mike Pyle

 

[potto]

Welcome to the board, Mike

Pressures are fine, if anything on the low side. I think it's just the way your tyres are, I'm afraid neither type is especially highly regarded as far as I know, they are both from the cheaper end of the scale and TBH you get what you pay for .

17s don't really suit the convertibles as well as 16s in my experience, they certainly look better but when you already have a chassis/shell that's as wobbly as my belly , you're better off with smaller wheels and tyres with enough sidewall to actually soak up some of the road's imperfections if comfort matters.

If it's tramlining and following white lines on the road etc, then there are a few things you can do:

1. Get the tracking checked and set to right in the middle of the tolerances, not at either extreme.

2. Get a steering rack clamp & brace from Abbott Racing, will transform your steering.

3. Swap the tyres asap for something like Dunlop SP Sport 9000/9090, Goodyear Eagle F1 GSD-3 or Conti Sport Contact2.

 

[potto]

Just noticed you have one type of tyre on one side of car and another on t'other. Swap them so you at least have the same type on each axle. Put the 94 tyres on the front and the 91s on the back I think would be best.

Which wheels do you have? If not Saab wheels, they may be the wrong offset and this could upset your handling.

 

[sussex2]

It seems strange that you appear to be using different tyres on each side.
If I am correct then in my opinion this cannot be helping handling and may indeed be putting you at some risk.
My opinion is that whenever trying to 'improve' any vehicle you have to consider the basics.
The car is based on a 80's Opel Vectra, never a paragon of handling virtue and famed for a nobbly ride; something which the Saab derivatives share.
The roof has been cut off and the earlier model convertibles have a reputation of being 'shakers' i.e. not very stiff and suffering from scuttle shake. This will further reduce the handling. On a 900 this problem will be exagerated.
Thus, you are not dealing with a sports car, more a boulevard cruiser.
If it sounds tough forgive me but I would get the car back to what the manufacturer intended and use it as such. The tyres as suggested elsewhere and the standard pressures.
Bear in mind that the steering rack is not mounted on a separate sub frame, as it should be, but bolted to the already wobbly bulkhead. The suggested Abbot racing rack brace could well improve matters a tad.

 

[NickWhite]

I'd be interested to know how others get on with 225/45/17s, including steps taken to reduce tramlining and the benefit/effect of each change.

My 9-3 tramlines like crazy (particularly where stips of tarmac meet) despite the Abbott rack brace and a change to Goodyear F1s (not the extra load ones).

 

[potto]

Mine still tramlines a little, on 225/45 contis, with Abbott clamp & brace, poly TCA bushes, Elksport rear ARB and Hirsch suspension kit, but nothing like it once was.

Tracking makes a big difference - last time I had mine set up on a 4-wheel laser jobbie and TBH I wasn't over impressed. It never felt quite right, I thought it was toeing out. Had a 54K service yesterday and asked the dealer to double check for me and sure enough, toeing out by 0.75mm, Not a lot, but now it's sorted (Viggen specs used - same basic setting as other 9-3s on 17" wheels but smaller tolerances) it feels far better.

I'm giving up on this laser alignment malarkey, I'm never completely happy with the car after it's done, and at £45 a pop .