[oscarguitar]

Hi,

I had to bite the bullet about 3 months ago and changed the original Bridgestones for a set of non RFT PS2 on 19" rims, due to the problems getting any. (Oct 2006 335d)

From the begining I had some concerns over the PS2 but thought this was mainly due to them being different and needing to be run in.

2500 miles later most of the concerns are met but I am still unhappy with the front end. The car just does not track as it used to with the Bridgestones. Turn in is inconsistent especially with small inputs and needs some correction in constant radius corners, never feeling really settled or giving a feeling of rock solid confidence. In a straight line if take my eyes of the road even for a second - looking at the nav, radio, idrive etc, the car is off and away either towards the kerb or the white line. These issues are more evident when cruising and improve when pushing on a bit.

I am running the tyres at 37psi front and 38.5psi rear. If the answer is tyre pressures, should I put the fronts up or down? Alternatively do I need to get the geometery checked? Your advice would be much apreciated

Thanks

[E92Fan]

Originally Posted by oscarguitar

Hi,

I had to bite the bullet about 3 months ago and changed the original Bridgestones for a set of non RFT PS2 on 19" rims, due to the problems getting any. (Oct 2006 335d)

From the begining I had some concerns over the PS2 but thought this was mainly due to them being different and needing to be run in.

2500 miles later most of the concerns are met but I am still unhappy with the front end. The car just does not track as it used to with the Bridgestones. Turn in is inconsistent especially with small inputs and needs some correction in constant radius corners, never feeling really settled or giving a feeling of rock solid confidence. In a straight line if take my eyes of the road even for a second - looking at the nav, radio, idrive etc, the car is off and away either towards the kerb or the white line. These issues are more evident when cruising and improve when pushing on a bit.

I am running the tyres at 37psi front and 38.5psi rear. If the answer is tyre pressures, should I put the fronts up or down? Alternatively do I need to get the geometery checked? Your advice would be much apreciated

Thanks

Hi there

I have the same tyres on my car, and it doesn't exhibit any of the problems you have. I find the turn-in pretty sharp (at 37psi) and certainly I don't need to be constantly adjusting the wheel mid-corner. In fact, the PS2s on my car have been exceptionally stable and true, in all manner of driving from bumpy city roads, to motorways and then on circuits.

I'd suggest, given the wandering you're experiencing even on a motorway/straight road, is that the alignment is out - our cars are very susceptible to misalignment and can become very twitchy and unstable as a result. Head down to your nearest dealer and ask for a full KDS setup, to include front and rear toe and camber too. Your tire pressures are absolutely fine by the way.

You should notice a world of difference afterwards (if, as I suspect, the alignment is out)

[trixman]

Think the easiest test is the pressures as its free. I've got 40 and 41 on mine, were lower before and didn't work great, these were the best compromise for me. Took some testing though.

Can't imagine a geo would do any harm, worth a shot. I can't believe all the positive press the Non-RFT get over the Bridgestones is false, so it must be something in the setup.

ETA: What E92Fan said

[E92Fan]

Originally Posted by trixman

Think the easiest test is the pressures as its free. I've got 40 and 41 on mine, were lower before and didn't work great, these were the best compromise for me. Took some testing though.

Can't imagine a geo would do any harm, worth a shot. I can't believe all the positive press the Non-RFT get over the Bridgestones is false, so it must be something in the setup.

Trixman - you have Vredesteins on your car no? Not suprised 40/41 works better - have found the Vredesteins flex a little more under load

[MOB]

I have 40R 38F pressure on my 19" PS2's - if they lose a couple of PSI I can really feel it - so I would experiment with your pressures to see if that helps.

[oscarguitar]

Thanks for the replies. Looks like the KDS could be the way the go but I might try jacking the pressures up a little first.

How much would the KDS cost? Do I need to have that done at a BMW dealer or are there independant outfits that would be able to do the job?

[oscarguitar]

MOB - reference the tyre pressures, if yours loose a couple of pounds what do you notice, the same as I described or something else?

[trixman]

Originally Posted by E92Fan

Trixman - you have Vredesteins on your car no? Not suprised 40/41 works better - have found the Vredesteins flex a little more under load

yep exactly

[marriedblonde]

I'm running my Vredsteins at 38f and 41r, as others have said BMWs in general seem very sensitive to tyre pressures and worn tyres!

Loosing a few piunds at either end seems to result in the car wandering.

Regarding getting an alignment done go to a decent tyre specialist to get it done.

J.

[MOB]

Originally Posted by oscarguitar

MOB - reference the tyre pressures, if yours loose a couple of pounds what do you notice, the same as I described or something else?

The car just feels wallowy and imprecise, loses its sharpness

[gIzzE]

There was a batch of PS2's that were kicking about that has really soft side walls, it was mentioned on mtorque.co.uk, was sorted by August and was only a problem for a month or two up till then.

[oscarguitar]

Thanks gIzze

I got my tyres on the 29th August - so that might be the problem, I'll read the article to find out if it is possible to identify the batch.

[oscarguitar]

I wasn't able to search for the article on the soft PS2s, have you got a link I could use?

[DonM3]

I also interested in reading about these soft walled PS2s as I've got pair waiting to go on my car. Had them a few months now.