Porker Posted April 7, 2008 Report Share Posted April 7, 2008 Hi all I am new to this forum - it was recommended by a friend. I have a 1990 Porsche 944S2 which until recently has always been fitted with Continental Contisports. I have just swapped them for a set of nearly new (less than 1,000 miles and manufactured in late 2007) Goodyear Eagles (F1s, I believe), which were acquired from another friend. The car seems to tramline much more with these than with the Contis. I'm running the same pressures (33F, 34R). Any thoughts? The new tyres have definitely taken the edge off the steering feel and accuracy. regards Nick Quote Link to comment Share on other sites More sharing options...
Porker Posted April 7, 2008 Author Report Share Posted April 7, 2008 (Reply by me so I can add email notification of your replies!) Quote Link to comment Share on other sites More sharing options...
jon Posted April 8, 2008 Report Share Posted April 8, 2008 Are they the GSD3s (arrow type tread) or the AS (would look more like the contis) Quote Link to comment Share on other sites More sharing options...
Porker Posted April 8, 2008 Author Report Share Posted April 8, 2008 Are they the GSD3s (arrow type tread) or the AS (would look more like the contis) They're GSD3s. regards Nick Quote Link to comment Share on other sites More sharing options...
Tony Posted April 8, 2008 Report Share Posted April 8, 2008 Hello Nick I assume these tyres are the same size in every aspect and you have the same wheels? Tramline due to tyres is normally assemetrical or symmetrical tyres with a continues unbroken band of tread. It's very unusual for a directional tyre like yours to suffer from this. So what to do?.... If they are the same size and wheels then manipulation of the pressure is a good start, 2psi down, test then 4psi up, test. Next would be the Toe (i assume this wasn't altered with the new tyres?).... I cannot offer any positions unless i know it's current position?... If it were correct static you also need a dynamic "pull-down" to ascertain what Toe gains you have aerodynamically and on the bump... From this you can establish the "Toe tendency" then set the static Toe to the tendency's mid-point. Quote Link to comment Share on other sites More sharing options...
Porker Posted April 8, 2008 Author Report Share Posted April 8, 2008 Hello Nick I assume these tyres are the same size in every aspect and you have the same wheels? Tramline due to tyres is normally assemetrical or symmetrical tyres with a continues unbroken band of tread. It's very unusual for a directional tyre like yours to suffer from this. So what to do?.... If they are the same size and wheels then manipulation of the pressure is a good start, 2psi down, test then 4psi up, test. Next would be the Toe (i assume this wasn't altered with the new tyres?).... I cannot offer any positions unless i know it's current position?... If it were correct static you also need a dynamic "pull-down" to ascertain what Toe gains you have aerodynamically and on the bump... From this you can establish the "Toe tendency" then set the static Toe to the tendency's mid-point. Tony, hi The tyres are exactly the same size as the originals and are mounted on the same rims front and rear. I'm running the pressures which seemed to suit the Contis, i.e. 33F and 34R. Geometry was left as before. I'll try the pressure change and report back. One thought I did have was that it is possible that the tyres, which had about 1,000 miles on them, were mounted on my car on the opposite sides to those which they were mounted on the car to which they were originally fitted. (That car was a 968, which has the same "chassis" as the 944 of course). However, I have driven around 400 miles on them since they were fitted and the tramlining effect is just as pronounced now as when they were first fitted. Thanks for your input so far. regards Nick Quote Link to comment Share on other sites More sharing options...
Tony Posted April 8, 2008 Report Share Posted April 8, 2008 Opposite sides? but the GSD is directional, so do you mean opposite ends. Thing to remember here it's not end of days, small changes in things like pressure or Geometry will act as a modifier all we need to do is find the most effective and cheapest option. Quote Link to comment Share on other sites More sharing options...
Porker Posted April 8, 2008 Author Report Share Posted April 8, 2008 Opposite sides? but the GSD is directional, so do you mean opposite ends. Thing to remember here it's not end of days, small changes in things like pressure or Geometry will act as a modifier all we need to do is find the most effective and cheapest option. Not sure I understand. They are directional, but surely you could remove a tyre from a rim which has been fitted to the NS of one vehicle and refit it to a rim which is destined for the OS of another vehicle. That is, unless they are directional and have a face which must be fitted towards the outside of the vehicle. Is my understanding correct? regards Nick Quote Link to comment Share on other sites More sharing options...
Tony Posted April 8, 2008 Report Share Posted April 8, 2008 Opposite sides? but the GSD is directional, so do you mean opposite ends. Thing to remember here it's not end of days, small changes in things like pressure or Geometry will act as a modifier all we need to do is find the most effective and cheapest option. Not sure I understand. They are directional, but surely you could remove a tyre from a rim which has been fitted to the NS of one vehicle and refit it to a rim which is destined for the OS of another vehicle. That is, unless they are directional and have a face which must be fitted towards the outside of the vehicle. Is my understanding correct? regards Nick Yes it is.... Sorry my thoughts were with pneumatic lateral drift, this cannot be changed by moving directional tyres..... So we are back with plan B... Tyre pressures first then Geometry calibration. Quote Link to comment Share on other sites More sharing options...
Porker Posted April 8, 2008 Author Report Share Posted April 8, 2008 Yes it is.... Sorry my thoughts were with pneumatic lateral drift, this cannot be changed by moving directional tyres..... So we are back with plan B... Tyre pressures first then Geometry calibration. No problem. I'll have a play with the tyre pressures and report back with the outcome. regards Nick Quote Link to comment Share on other sites More sharing options...
jon Posted April 9, 2008 Report Share Posted April 9, 2008 One other thought is how many miles have you done on the GSD3s? You said you got them with 1000 miles on from a friend, that means the tyres will have adapted to his geometry so will feel odd on your car until they reset to yours. Incidentally i was thrashing a 968CS around rockingham on Sunday. They need a limited slip diff badly! Quote Link to comment Share on other sites More sharing options...
Porker Posted April 9, 2008 Author Report Share Posted April 9, 2008 One other thought is how many miles have you done on the GSD3s? You said you got them with 1000 miles on from a friend, that means the tyres will have adapted to his geometry so will feel odd on your car until they reset to yours. Incidentally i was thrashing a 968CS around rockingham on Sunday. They need a limited slip diff badly! About 400 miles so far. I will put another couple of hundred on and try the tyre pressure variation and let you know how I get on. The 944 Turbo came with an LSD but it wasn't available AFAIK on the 968, although it's possible the 968 Turbo had one. Nick Quote Link to comment Share on other sites More sharing options...
Tony Posted April 9, 2008 Report Share Posted April 9, 2008 One other thought is how many miles have you done on the GSD3s? You said you got them with 1000 miles on from a friend, that means the tyres will have adapted to his geometry so will feel odd on your car until they reset to yours. Incidentally i was thrashing a 968CS around rockingham on Sunday. They need a limited slip diff badly! My, my you have been paying attention Quote Link to comment Share on other sites More sharing options...
Porker Posted April 9, 2008 Author Report Share Posted April 9, 2008 OK, so I have now dropped the pressure to 31F (R same as before at 34) and it seems to have made a significant improvement. I have covered a further couple of hundred miles on dry roads so it is also possible that the tyres are scrubbing in to my geometry, although if they are it's not that detectable, since the improvement (reduction of tranlining) occurred as soon as I reduced the pressures by 2psi. I'll probably drive it like this for a while and then try 35psi, and then 33 psi again to see what difference it makes. I may even try 30psi to see if this yields a further improvement. Much appreciate the pressure tip - so far it seems to have done the job. regards Nick Quote Link to comment Share on other sites More sharing options...
Tony Posted April 9, 2008 Report Share Posted April 9, 2008 Excellent...... Just goes to prove small changes is psi really does allow flexibility in the rigidity of the tyre sidewall and acts as a tool to manipulate tram-lining....... In most clubs members would say "no way".... In wim we say "yes way" Quote Link to comment Share on other sites More sharing options...
Shimsham Posted November 20, 2008 Report Share Posted November 20, 2008 Hi. Could anyone tell me the correct tyre pressure for the HA Tourer sport cdti 2.2 the only presure readings i have are inside the drivers door and that is is in psi which i dont understand. Quote Link to comment Share on other sites More sharing options...
Tony Posted November 20, 2008 Report Share Posted November 20, 2008 Hi. Could anyone tell me the correct tyre pressure for the HA Tourer sport cdti 2.2 the only presure readings i have are inside the drivers door and that is is in psi which i dont understand. PSI is the language we use in the UK..... what does the pillar sticker say? Quote Link to comment Share on other sites More sharing options...
Shimsham Posted November 21, 2008 Report Share Posted November 21, 2008 Hi. Could anyone tell me the correct tyre pressure for the HA Tourer sport cdti 2.2 the only presure readings i have are inside the drivers door and that is is in psi which i dont understand. PSI is the language we use in the UK..... what does the pillar sticker say? Sticker on the pillar says. 225x45x17zr 95w 180km/h 230[2.3]33-220[2.2]32 180km/h 230[2.3]33-220[2.4]35 180km/h230[2.3]33-270[2.7]39 Regards Quote Link to comment Share on other sites More sharing options...
Tony Posted November 21, 2008 Report Share Posted November 21, 2008 Hi. Could anyone tell me the correct tyre pressure for the HA Tourer sport cdti 2.2 the only presure readings i have are inside the drivers door and that is is in psi which i dont understand. PSI is the language we use in the UK..... what does the pillar sticker say? Sticker on the pillar says. 225x45x17zr 95w 180km/h 230[2.3]33-220[2.2]32 180km/h 230[2.3]33-220[2.4]35 180km/h230[2.3]33-270[2.7]39 Regards The last two sets of figures are bar and PSI won't one of them do Quote Link to comment Share on other sites More sharing options...
Shimsham Posted November 21, 2008 Report Share Posted November 21, 2008 Hi. Could anyone tell me the correct tyre pressure for the HA Tourer sport cdti 2.2 the only presure readings i have are inside the drivers door and that is is in psi which i dont understand. PSI is the language we use in the UK..... what does the pillar sticker say? Sticker on the pillar says. 225x45x17zr 95w 180km/h 230[2.3]33-220[2.2]32 180km/h 230[2.3]33-220[2.4]35 180km/h230[2.3]33-270[2.7]39 Regards The last two sets of figures are bar and PSI won't one of them do Hi Tony. Yeh one will do but which one is it do you think 33 Front & 32 Rear. Quote Link to comment Share on other sites More sharing options...
Tony Posted November 21, 2008 Report Share Posted November 21, 2008 Hi. Could anyone tell me the correct tyre pressure for the HA Tourer sport cdti 2.2 the only presure readings i have are inside the drivers door and that is is in psi which i dont understand. PSI is the language we use in the UK..... what does the pillar sticker say? Sticker on the pillar says. 225x45x17zr 95w 180km/h 230[2.3]33-220[2.2]32 180km/h 230[2.3]33-220[2.4]35 180km/h230[2.3]33-270[2.7]39 Regards The last two sets of figures are bar and PSI won't one of them do Hi Tony. Yeh one will do but which one is it do you think 33 Front & 32 Rear. Assuming there's no adverse pressure related tyre wear then yes. Quote Link to comment Share on other sites More sharing options...
jon Posted November 22, 2008 Report Share Posted November 22, 2008 Start at stock pressures then if you're not happy with how the car feels come back here and explain what's wrong and we'll put it right Quote Link to comment Share on other sites More sharing options...
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