new tyres - rear feels like jelly!

[kennyboy]

Just bought 2 new pzero assymetrics for my C2 to replace the badly worn ones already on. The replacements are exactly the same tyre as already on.

Took the car out of my favourite stretch immediately hoping to enjoy some extra confidence on the twistys. But what I got was the complete opposite!

The car now feels all over the place at the back end - not loosing grip but feels like jelly, can't 'feel' the back of the car like before and if anything feels like it's gonna take-off at the back on high speed bends, feels wallowy - completely removes any confidence of cornering above 80mph or cornering under throttle, very disconcerting!

I'm hoping the issue is down to one or both of these:
1. The guy at the tyre garage says I need to go back to get the nuts tightened again after 100 miles - I've done about 80 now.
2. The tyres need a lot of bedding in.

I started at 34psi as recommended by guy at tyre place then went up to 36 as porsche recommend and no improvement.

Has anyone experienced similar? - as it stands at the moment I daren't do anything on the road!

Maurice - I've posted this seperate to the kinematic discussion we had as I'm thinking that whether that needs doing or not, the new tyres have still had a dramatic affect on handling on their own. :-(

 

[Sundeep]

tyre fitter could have knocked out tracking or alignment ?

 

[38F3E1]

All tires have to be run in before they develop their true handling characteristics. I have been running pzero assimetricos and I find them to feel good.

Also your old tyres will have worn to the camber and alignment on the car and therefore have good contact with the road. New tyres may not have such good contact if these settings are bad.

So it could be just bedding in the new tyres or related to the suspension set up being non optimal. Sorry I can't give a better answer.

Ian.

 

[bones]

Agree with Maurice and Ian. New low-profile tyres on my antiquated - but excellent - SCs suspension made the car feel 'squidgy' for about 200 miles after that it was business as usual.

 

[Guest]

I had the same issue on my 996.
The rears wear faster than the fronts (or at least do for me), so I only changed the rears.
I took it easy to start with but was still suprised that even after 100 miles it still did not feel right. I checked the pressures, but all was well, but I still had the stability control braking the wheels and the back felt loose. Cornering speed was reduced by 10-20 miles an hour (i.e. a 70 mph corner was taken at 55 to avoid the light).

However, after some more miles (I don't have a figure) it all settled down and business is very much now back to normal.
The tyres I have are Continentals, but the issue is the same for all makes.
It just takes longer than I expected (the Yokohamas I used to use on the previous car did not exhibit this characteristic to anything like the same extent).

 

[kennyboy]

Excellent! with this info and the same from rennlist I'm happy again - thanks boys. don't worry I'll find something else soon to get obsessive about - kinematics probably!

I'm gonna take it easy for another 200 miles like you say maurice - I felt reasonably confident on the old tyres so whether the suspension/setup needs sorting or not, atleast I should get back to the old feeling soon.

Maurice/Vic - did you make mincemeat of the RS then?!