N Rated Tyres

[AVI_8]

I've had my 911 for 6 years now, it had fairly new Conti Sports when I bought it, It was time to replace the tyres this year so I did some research and saw online several Continental tyre types (Conti sport 2, Conti sport 3)

Having read the description on the continental website I bought 4 sport 3 tyres as this was the newer type. 255/40/17 and 205/50/17

It wasn't until after the tyres were fitted that I found out that Porsches are supposed to have N rated tyres, the guy at the tyre centre told me that although the tyres I bought are good tyres, they're not rated by Porsche.

I wouldn't have been too bothered about that but when driving back through country roads I felt that the car didn't seem to be as sure footed as before, it's not that it lacks grip but the best way I can describe it is that it feels that there is more flex in the sidewall, I've always found the 964 to be a great car through corners, very easy to balance it with the throttle, now when I do that it feels as though it wants to oversteer even though the tyres are not physically skidding if that makes sense.

I don't know if I'd just got used to the feel of the car with less tread and now that there's more tread there's more flexing? I've owned a few sports cars over the years and It's not something I've noticed before with other cars.

I'd be interested in hearing if anyone has found this after fitting new tyres, I paid £555 for them and have a feeling that I'm going to have to go and get another set and get what I can get for the ones I've just fitted on ebay.

An expensive mistake possibly! But I don't want to compromise handling.

The pressures are ok I've always used 45 on the back and 35 on the fronts as I found higher pressures on the rears gave a sharper feel.

Some input from some of you track focused guys would be good thanks

 

[Lancerlot]

N rated tyres are developed specifically for Porsche. These may differ in terms of compound and/or construction to those without this rating. Porsche recommend using the same 'N' rating number on all 4 wheels.

You have 2 options 1.) replace with 'N' rated tyres and sell on the others 2.) Stick with the present tyres until they are bedded in - it may take 1K miles or so and see how they feel then.

All new tyres feel slightly weird at first until the mould releasing agent and high spots disappear.

Regards,

Clive.

 

[Hacki]

ORIGINAL: Lancerlot

Stick with the present tyres until they are bedded in - it may take 1K miles or so and see how they feel then.

All new tyres feel slightly weird at first until the mould releasing agent and high spots disappear.

Regards,

Clive.

+1

I had several sets of tyres (N-rated and non N-rated), they all felt different and they needed their time in the beginning. Conti for sure is a good tyre.

I never tried such a high cold pressure on the back, that is def. too much, esp. when you start to heat the tyres up. 33 all round should do it, overheated rears will indeed cause snap oversteer.

On track days I start with 25 front and 23 rear (cold tyres), they go up to 35 (hot tyres) quickly. Good pressure on hot tyres is 33 IMHO.


Hope this helps,

Hacki

 

[AVI_8]

Guys, thank you both for your replies, I will give it more time to let them bed in and reduce the pressure at the rear, my 964 unfortunately isn't an RS, it's just a C2, the standard tyres for that was 46 psi on 16" rims, Mines got 17" and when I got it it just seemed to feel a bit tighter with increased rear tyre pressure, but I'll reduce them and give that a go.

Thanks again

 

[Laurence Gibbs]

I agree with Hacki , 964's with 17 rims Porsche recommends 36 psi and they are nearly always better at slightly less. at 45 psi you must be vastly reducing you tyre footprint at the back and that probably explains the oversteer feeling.

 

[h_____]

ORIGINAL: Lancerlot

N rated tyres are developed specifically for Porsche. These may differ in terms of compound and/or construction to those without this rating. Porsche recommend using the same 'N' rating number on all 4 wheels.

You have 2 options 1.) replace with 'N' rated tyres and sell on the others 2.) Stick with the present tyres until they are bedded in - it may take 1K miles or so and see how they feel then.

All new tyres feel slightly weird at first until the mould releasing agent and high spots disappear.

Regards,

Clive.

+2 good advice....wait until the releasing agent has gone, drop the pressure to factory again and try adjusting from there. The new tyres may have less stiff sidewalls, or deeper treads which would result in the feeling of movement before slipping.

As the tyres are already second hand running them for a little longer before you decide to change wont hurt.