Phil R

I have just had fitted a set of S02 pole positions and need a little help...
The car has done about 900 miles on them and the handling has gone to pieces it feels that the **** end is going to let go everytime you give it some (not as bad as mine though!) Is this a common problem with low miles on them ? personally i think its a tyre pressure problem I have set them as recommended by Subaru but it really is bad. As I drive the car progressively could someone recommend a suitable set of tyre presures for front and back.

Did

Phil,
I had the same problem with my 215/40/17 So2 pp's a while back. For a few hundred miles (not 9 though) they were absolutely cack.

I put it down to them bedding in- which to some extent it was, but then I did find that they had been set to 40psi all round. Moving to 36's helped.

I am now experimenting, starting from 36 downwards. If you do a search there are quite a few threads about pressures that are worth reading.
Did

Darren Soothill

Try swapping the front tyres to the rear and the rear to the front as the fronts get alot more wear on them and it could be that the rears are still trying to get rubbed up. I certainly found that with my Toyo's.

I usually run somewhere around 32 front 31 rear with the Toyo's.

Darren

GaryC

Try 36psi front and rear - you'll think you've just had £1000 worth of suspension mods!

Phil R

Did
thanks for the reply. I started at about 32 ish front and 28 ish in the back. I too am trying to figure them out. They are so unpredictable and let go ever so easily totally unlike the P Zero's. These would always let go gently and you can power on or power off the slide easily. I will try upping the rear pressure to the same as the front and see what happens

GaryC

I was told by prodrive not to swap tyres (front to back etc) as they 'bed in' differently and changing will screw the handling and grip up.

Did

Phil,
28 rear sounds abit low to me (but then who am I to say ;-) )

I would have thought 32/28 would make it a bit rearward biased, don't know about the snatchyness though. Why not try as Gary says and bring them up, then start coming down again.

See ya
Did

Phil R

Thanks for the advice everyone i'll try 36 and let yo know what happens.

Phil R

Steve
Thanks for the reply.
The tyres have done over a thousand miles now and are still as bad as they were when i bought them (Which I feel indicates incorrect tyre pressure).
The tyres are "letting go" from 50 - 120 mph on every road surface and are certainly scrubbed in. Its not so much the correction that i'm worried about its the transformation from grip to no grip that is frightingly quick.
Even when the P Zero's were way down on tread they never made the car handle like this.
I will find Bridgestone's technical nuumber and give them a ring in fact, it might be worth having a page of useful number for easy access.

Steve Prockter

Phil.......what MY car have you and do you have any suspension mods? Do you know what your geometry settings are?

Steve

Steve Prockter

Phil.........SO2's can be a bit slippery for the first few hundred miles. The trick is to give them a good thrashing straight out the box.

It should be noted however that it is pretty damn difficult to accurately assess the effect of different tyre pressures without extensive testing like on a track or somewhere. I can recommend 29 rear 32 front for 17 inch 215 SO-2's which should give you a comfortable ride quality and good all round wet and dry road grip.

The "wagging tail" sensation you are experiencing might be due to the greater level of grip derived from the SO2's meaning that the speed is higher when the tyres break traction and thus the reaction of the car slightly more exaggerated.

If your tyres are set somewhere in the mid regions suggested on the BBS, your car ought to possess a pretty high level of grip, perhaps slightly lower pressures will improve wet weather handling and slightly harder for dry weather. So long as the differential between front and back is a few psi the balance should be much the same whether you are running 29/32 or 33/36, but perhaps the level of grip will differ.

In all seriousness if you are concerned about a "wagging rear end", first go on the MIRA course before worrying too much about pin point accurate tyre pressures. I assure you a day at MIRA won't make you think twice again about tyre pressures. Believe me when you realise you can rescue your impreza from a spin of over 90 degrees and still pull it back, you'll be thinking differently.

Steve

johnfelstead

you may have some faulty tyres.

Very unusual i know but all tyres are still hand made.

I used to do some xray and eddy current testing machines used on tyres and you can occasionally get a bad batch that have not been laminated properly, guy pissed, distracted etc.

Very unusual these days but it is a posibility.

Phil R

Steve
Its an RB5 and upping the tyre pressures all round has certainly made a difference. Over bumpy roads the suspension is now really working and the tyres are not it seems soaking any of the travel up. It has made the ride really hard and lively which i dont mind considering the alternative...
Tyre pressures is 35 f + r and i might try lowering slightly all round but at the moment it really is miles better...
I managed about 11k on the P Zero's before they were shot and the way that these are marking on the edges i dont think they are going to last that long.
I thought about having the Prodrive setting done at Micheldever where I bought the tyres from but though the car is more responsive the front tyre wear apparently (inside) is increased. Considering what I am paying for tyres and petrol at the moment I thought I would give it a miss.
thanks for the advice all
Phil.