tyre pressures ?

[davepaul993]

tyre pressures for a 993 c2 1997 on 17 inch ?
when i got the car i was told 36lb all round as it says in the book but, after taking the wheels off to give them a clean up i noticed that the rears are wearing in the centres, what do you suggest ?
dave

 

[968er]

Some people think that it is 44lbs at the rear for 17" wheels rather than 36lbs, so could have been run at that pressure and caused the wear.

 

[Pickled Piper]

I run my 17s at 36psi and am getting even wear. The wear pattern that you describe is not necessarily always an indicator of over inflation. It is possible that the car has been used predominantly at high speed on the motorway. In this condition the tyre "bows" out in the centre of the thread area.

pp

 

[Sundeep]

ORIGINAL: Pickled Piper

I run my 17s at 36psi and am getting even wear. The wear pattern that you describe is not necessarily always an indicator of over inflation. It is possible that the car has been used predominantly at high speed on the motorway. In this condition the tyre "bows" out in the centre of the thread area.

pp

indeed 36PSI on 17's is fine...... although there seems to be quite a performance difference in those different N rated tyres as the temps heat up..........

I actually used to mine at 34 PSI cold on my previous set of Michelin Pilot Sport N2 tyres (excellent tyres and very recommended) which were in the zone at around 36psi when they were warmed up as they were a bit wayward at over 38PSI...... although track PSI's were 36PSI HOT, which meant starting off the 1st lap at 30-32psi cold

however I now have a set of new Pirelli P-Zero Rosso N3's all the way around, so I am starting off back at the OEM spec 36 PSI cold and seeing how they develop from there.....

 

[burrow01]

Hi Sundeep

How do the Pirellis compare to the Michelins for handling etc

You seem impressed with the Michelins, what made you go for the Pirellis - just fancied a change?

Pete

 

[Sundeep]

Pete

impressed with the Michelins although I would have liked the new PS2's to be available in the 993 17's sizes, but they are not, such a limited choice in N rated tyres for 17's..... and the current N2's are a development of the old tyre as opposed to the lastest michelin tech..... only issue was that the last few mm disappeared quickly as opposed to my old continential sport 2's that seemed to last forever....

but I actually wanted to try out the Pirelli's to see what they were all about, as I haven't before but had avoid thier range due to issues with supply of existing N spec tyres when they introduce new N rated tyres...although they were slightly better priced it wasn't much of a real difference...

straight away they have a different driving feel.... but has taken a short while to bed them in properly after all the rain of late

regards

 

[burrow01]

ORIGINAL: Sundeep

straight away they have a different driving feel.... but has taken a short while to bed them in properly after all the rain of late

Better or worse [] or just different?

Pete

 

[Sundeep]

ORIGINAL: burrow01

ORIGINAL: Sundeep

straight away they have a different driving feel.... but has taken a short while to bed them in properly after all the rain of late

Better or worse [] or just different?

Pete

different, but then the Michelins always felt hooked up in the dry but early days as I only got a real idea of the Michelins after some miles.... and in fairness the cars ride height has just gone up 5mm and there is always a bedding in period....
athough worn out Conti's last very well to the end.....

 

[oliverjamesthomas]

Sundeep

What pressures are you running?. I've got Rossos on 17's and from manufacturer's stated 36 psi cold, I'm hitting 43 psi rear and 40 psi front and that's just normal road driving! I'm suffering some really nasty vibrations at motorway speeds, especially from the rear, so I've dropped them to 32 psi cold to see if I can cure it. It's definitely the Rossos - I've just bought a set of track wheels with brand new Conti's on and when I put them on, I'm not suffering the same problems.

First thoughts are they're not a patch on the Conti's, which I really liked. My last set lasted an age and that was including track work. The Rossos are noisier and the car tramlining all over the place. I'm finding the steering wheel shakes around all the time and I can honestly say they don't seem to grip any better! Granted, there may be a bedding in period, but if it carries on, the Conti's will be the road tyres and I'll waste the Rossos on the track!

Regards

 

[Sundeep]

ORIGINAL: MoC2S

ORIGINAL: Sundeep
. and in fairness the cars ride height has just gone up 5mm and there is always a bedding in period....

Strange ... why did this happen ... ?

new tyres of course ! old tyres were on 2/3 mm and I'm now on 8mm (or so one hopes) so that will be 5mm more...... and I'm starting on OEM pressures so a tad harder than what I ran the old Michelin Pilot Sport N2's

 

[Sundeep]

ORIGINAL: oliverjamesthomas

Sundeep

What pressures are you running?. I've got Rossos on 17's and from manufacturer's stated 36 psi cold, I'm hitting 43 psi rear and 40 psi front and that's just normal road driving! I'm suffering some really nasty vibrations at motorway speeds, especially from the rear, so I've dropped them to 32 psi cold to see if I can cure it. It's definitely the Rossos - I've just bought a set of track wheels with brand new Conti's on and when I put them on, I'm not suffering the same problems.

First thoughts are they're not a patch on the Conti's, which I really liked. My last set lasted an age and that was including track work. The Rossos are noisier and the car tramlining all over the place. I'm finding the steering wheel shakes around all the time and I can honestly say they don't seem to grip any better! Granted, there may be a bedding in period, but if it carries on, the Conti's will be the road tyres and I'll waste the Rossos on the track!

Regards

Oliver

now I can only speak for the Michelin's and the Conti's that I ran before, but I found that anything over 39/40PSI after the tyres had heated up and the Michelin's handling was a bit lively. and after a few track days I found that HOT the michelins did not like going above 38 and I kept them in the 32 to 38 zone for track days (weather conditions and track surfaces permitting)

as a result I eventually settled for a cold 34 PSI setting if I knew I was doing more than the supermaket run, as even on a motorway run the heat levels could be 38+ which meant they were in the szone for any A-B roads that I may have hit.....

now that is just what I experienced on my michelins and all via trial and error, it was just after a few track miles I felt that the road performance wasn't sharp and the OEM 36PSI cold can work for day to day town driving, but I was happier with a lower starting balance and anything above 42PSI was wayward....

assuming that makes sense...... just my experiences from the last year.....

btw, I agree the Rosso's N3 are instantly noiser

regards

 

[RichardLW]

Rossos take a fair time to bed in - a couple of thousand miles in my case but I am now very happy with them. Very odd and unpleasant to begin with but after a while, great tyres.

 

[oliverjamesthomas]

Thanks for that Sundeep. I was beginning to think they were a really bad investment. I'm experimenting at the minute with 32 psi front and 34 psi rear, so I'll see how things go on. When I had the car aligned, the front / rear differential was a suggestion made to me and I found it suited the car quite well, with turn-in slightly improved.

As for a couple of thousand miles Richard, I guess it means I'll just have to drive the car more - what a chore [][]

The ironic thing to me is that we have the 'N' requirement, Mercedes have their version and we are told the whole approval process costs a fortune and takes significant time. Look in the handbook though and we're given one set of pressures for a certain wheel and tyre size. I can back to back with two sets of wheels, one fitted with Rossos and the other with Conti's and am finding the pressure requirements totally different. Am I being pedantic, or do the manufacturers not consider tyre pressures to be as significant as sidewall construction? Or alternatively, have I just given the reasoned proof that the 'N' rating concept isn't as bullet-proof as some would have us think[8|]

Regards

 

[Sundeep]

Richard, that's good to know about the Rosso's are they are a bit of a pig at the moment !

ORIGINAL: oliverjamesthomas

The ironic thing to me is that we have the 'N' requirement, Mercedes have their version and we are told the whole approval process costs a fortune and takes significant time. Look in the handbook though and we're given one set of pressures for a certain wheel and tyre size. I can back to back with two sets of wheels, one fitted with Rossos and the other with Conti's and am finding the pressure requirements totally different. Am I being pedantic, or do the manufacturers not consider tyre pressures to be as significant as sidewall construction? Or alternatively, have I just given the reasoned proof that the 'N' rating concept isn't as bullet-proof as some would have us think[8|]

Regards

couldn't agree more as it would be nice if they told us the tyres pressures for their tyres on set cars, which are already defined by porsche

and part of me didn't want to change from the michelins as I'd finally figured them out.. although who knows how different a set of identical tyres can be in manufacturing processes ! but wanted to try another brand......so here I am [&:]

 

[SAB]

Sundeep

I need to replace all 4 Contis on my 993 Cabrio. A year on from your switch from Michelin to Pirelli, what are your thoughts on Rossos v Pilot Sports v Contis v anything else (for 100% road/ 0% track use).

Regards


Steve