Ruf 19" on 964?
10-21-2008, 06:04 PM
#17
Three Wheelin'
I'm curious why you ask this question. 19" wheels, fitted with the correct tyres should have much the same rolling radius as any other size wheel - whether it be a standard 16", 17" or 18". The tyre aspect ratio is reduced as the wheel size gets larger so the overall tyre size doesn't change very much.
Bump steer is only induced by the reduction of ride height causing the tie rod angle to change so a bump causes the effective length of the tie rod to increase, giving an automatic toe out effect - hence the bump steer. With the tie rod at the correct angle a bump will only cause the effective length to shorten, hence give rise to a toe-in and less bump steer.
Tyre rub is more an effect of increased tyre width rather than a change in diameter. It's common to increase the width when changing wheels - hence the caution - but, again, the increase in wheel diameter will have little or no effect on tyre rub.
Dave
Bump steer is only induced by the reduction of ride height causing the tie rod angle to change so a bump causes the effective length of the tie rod to increase, giving an automatic toe out effect - hence the bump steer. With the tie rod at the correct angle a bump will only cause the effective length to shorten, hence give rise to a toe-in and less bump steer.
Tyre rub is more an effect of increased tyre width rather than a change in diameter. It's common to increase the width when changing wheels - hence the caution - but, again, the increase in wheel diameter will have little or no effect on tyre rub.
Dave
10-21-2008, 11:47 PM
#19
Rennlist Member
19's do not have the proper proportions with a 964 IMO. 18s are pushing it. But to each their own.
10-22-2008, 03:43 PM
#20
Rennlist Member
I'm curious why you ask this question. 19" wheels, fitted with the correct tyres should have much the same rolling radius as any other size wheel - whether it be a standard 16", 17" or 18". The tyre aspect ratio is reduced as the wheel size gets larger so the overall tyre size doesn't change very much.
Bump steer is only induced by the reduction of ride height causing the tie rod angle to change so a bump causes the effective length of the tie rod to increase, giving an automatic toe out effect - hence the bump steer. With the tie rod at the correct angle a bump will only cause the effective length to shorten, hence give rise to a toe-in and less bump steer.
Tyre rub is more an effect of increased tyre width rather than a change in diameter. It's common to increase the width when changing wheels - hence the caution - but, again, the increase in wheel diameter will have little or no effect on tyre rub.
Dave
Bump steer is only induced by the reduction of ride height causing the tie rod angle to change so a bump causes the effective length of the tie rod to increase, giving an automatic toe out effect - hence the bump steer. With the tie rod at the correct angle a bump will only cause the effective length to shorten, hence give rise to a toe-in and less bump steer.
Tyre rub is more an effect of increased tyre width rather than a change in diameter. It's common to increase the width when changing wheels - hence the caution - but, again, the increase in wheel diameter will have little or no effect on tyre rub.
Dave
