[on_the_virge]

Recently changed my run flats to non run flats and put the less than rigid feel down to the softer side walls of the non run flats but recently it feels decidedly unstable, especially when on the motorway..

Any ideas???

Cheers
Virge

[dopper99]

Obvious one is tyre pressures?

[a803sgo]

Balancing?

[on_the_virge]

Originally Posted by dopper99

Obvious one is tyre pressures?

Will get em checked tomorrow, tyre pressures on the car looked right.

[Ashway]

uneven or over inflated tyre pressures

[SkyJawa]

Incorrect load rating?

[Soul_Glo]

Camber? Toe? Alignment? Tyre Pressure? Something up with suspension?

When I swapped to non RFT on an old E92 the alignment was way out of whack. One of the control arms was also worn so I replaced both with Meyle HD. The car felt more controlled after that. I think at around 80k miles the suspension was due for an overhaul anyway.

I opted for uni royal and the side walls were so soft corners became interesting!

What tyres did you put on?

[Watsey]

Although it won't have changed as a result of changing tyres, assuming of course that the size and aspect ratios are the same, but it's worth getting a proper 4 wheel alignment done.

My F31 benefitted from a Hunter 4 wheel alignment - it wasn't out by much but has yours ever been checked to factory spec settings ?

[on_the_virge]

I put Falkens on but I can't see this been the problem as the reviews for these were good. The size and loads are correct, what is the correct tyre pressures for 225/40/19 and 255/35/19?

[Watsey]

Between 2.4-2.6 Bar - it seems to be down to personal preference. I run mine (those sizes; Michelin Pilot Super Sports) at 2.5 Bar all round.

[dopper99]

And check your tyre pressures when the tyres are cold, on your drive before you go anywhere.

Dont drive to a garage and check them, waste of time.

[on_the_virge]

Put 2.5 bar (36 psi)in this morning and so far so good....one of the fronts was at 39...

[GEP77]

Non runflats do certainly feel quite different and if you're very used to how the RFTs behave can feel a little odd at first.

I have found on some sections of the motorway network (Lane 3 of Junction 9-8 of the M25 being a classic example) the car is quite prone to tramlining due to the terrible surface condition. This I've found does feel different depending on whether you have RFT, Non-RFT or a square RFT setup (as I have for Winter atm). The best performer is the square setup incidentally.

I think this is likely to get worse as time goes on due to the pathetic level of competant resurfacing going on.

[creepy coupe]

I think this comes back to F3# not being transformed as much as the E9#'s. The f3# tend to be softer in the damping department. So together with softer side walls, it can feel a bit odd.

[Edinburra]

Who fitted them? Get back to them and tear a strip off them. They are responsible, they should know better, they should have put the correct amount of air into your tyres after fitting. No excuses. Dangerous, dangerous, dangerous.

[430GH]

I believe I had the same feeling a few years back when I replaced the worn out Bridgestone R/F to PZero R/F on the rear of E92 318D. I thought they had replaced the 2 tyres with jelly and didn't feel that stable being pushed round high speed bends (Example M5 - Swindon A417) The tyres were filled to the correct pressure and were fitted in the correct orientation.

I would have thought what I felt would be increased by putting on normal tyres with softer side walls...

[robbiep]

Originally Posted by on_the_virge

I put Falkens on but I can't see this been the problem as the reviews for these were good. The size and loads are correct, what is the correct tyre pressures for 225/40/19 and 255/35/19?

Most reviews for tyres are written within a few days of getting them fitted.
So they are being 'reviewed' compared to generally old, worn-out tyres. Of course the reviews are generally good !
The 'poor' reviews are normally down to failures in fitting, supply, or some other cockup, and very little to do with the tyres themselves.

As to tyre pressures, you may well find you need slightly higher pressures for non-RFT tyres compared to RFTs. The sidewall flexes a lot more, and needs the additional pressure in the tyre to retain it's shape.