Inside wheel lift - tire pressures?
#1
Inside wheel lift - tire pressures?
I am looking at the high res pics that I received last night of my Sebring DE day. In a couple of the high speed cornering pics, I can clearly see that the inside tire contact patch is reduced by what looks like about 1/4 of the tire width - looks like the inside wheel / tire is lifted 911 style (but to a lesser degree) under hard cornering. You can kind of see it in the low res pics called 'Hold on' and 'Right' at the link below. In the high res pics it is very clear.
http://f1.pg.photos.yahoo.com/ph/nee...nan1/my_photos
I had my warm tire pressures set to 36 psi front and 44 psi rear (I have to check my notes to confirm).
Is this reduction of contact patch normal for a stock weight 928 under high lateral acceleration? Are my tire pressures set to high for a DE, contributing to this effect?
Thanks!
......Cameron
'91 Euro GT
http://f1.pg.photos.yahoo.com/ph/nee...nan1/my_photos
I had my warm tire pressures set to 36 psi front and 44 psi rear (I have to check my notes to confirm).
Is this reduction of contact patch normal for a stock weight 928 under high lateral acceleration? Are my tire pressures set to high for a DE, contributing to this effect?
Thanks!
......Cameron
'91 Euro GT
#3
Great photos! I like "Rain" the best. Perhaps 'cause it reminds me of the "Wet Coast" out here. I think the photos show what I would expect from a stock 928. The reduced contact patch on the inside tire is normal as weight is transfered to the outside tire. I don't think your tire pressures can be adjusted to have much effect on this.
Glenn
Glenn
#4
A way to check next time is to bring along an infrared thermometer and take temp readings across the width of the tire and check your tire pressure at temp, then adjust those pressures up or down to get more tire contact through the corners within the allowance of your suspension.
#5
cameron,
not necessarily abnormal, and definitely more related to suspension than tires. softer springs and less sway bar will tend to make this more apt to occur.\
even big time springs and heavy swaybars can allow it:
not necessarily abnormal, and definitely more related to suspension than tires. softer springs and less sway bar will tend to make this more apt to occur.\
even big time springs and heavy swaybars can allow it:
#6
how are you wearing the tires out? i dont know the degree of g loading on that turn, but if it is significant, then this is normal.
if not, then you may have too much camber. camber for our cars in race form should be in the 1.5 degree range. if you are 2 in front, that probably is way too much.
if not, then you may have too much camber. camber for our cars in race form should be in the 1.5 degree range. if you are 2 in front, that probably is way too much.
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#8
Re: Inside wheel lift - tire pressures?
front is fine, rear is brain dead off! car feel loose (ha ha ha) get that 44 lbs down to within a couple of lbs of the front pressures. I hope we are talking about DOT hoosiers or other DOT tires, otherwise, if you are running real slicks, you are WAY to high .
based on the picture, your not pulling too many Gs. you probably have a little too much camber up front. i would guess 2+ degrees.
I forgot what suspension you are running, but you have no body roll or compression at all.
mk
I had my warm tire pressures set to 36 psi front and 44 psi rear (I have to check my notes to confirm).
Is this reduction of contact patch normal for a stock weight 928 under high lateral acceleration? Are my tire pressures set to high for a DE, contributing to this effect?
Thanks!
......Cameron
'91 Euro GT [/B][/QUOTE]
based on the picture, your not pulling too many Gs. you probably have a little too much camber up front. i would guess 2+ degrees.
I forgot what suspension you are running, but you have no body roll or compression at all.
mk
I had my warm tire pressures set to 36 psi front and 44 psi rear (I have to check my notes to confirm).
Is this reduction of contact patch normal for a stock weight 928 under high lateral acceleration? Are my tire pressures set to high for a DE, contributing to this effect?
Thanks!
......Cameron
'91 Euro GT [/B][/QUOTE]
#10
Thanks for the feedback. I have club sport front springs, stock rear springs. Standard (but pretty new) Boge shocks all around. Tires are Continental ContiSport II's. Re the camber in the front, it should be in spec for a stock alignment and setup. I did not tweek it for DE.
I thought the rear tire pressure was too high as well. Someone at the tech inspection told me that 44psi was a good rear tire pressure for this car. I wasn't sure, being my first PCA DE. He stated this so matter of factly that I went with it. Live and learn.
Thanks for the pics. Damn fun to look at pics.
.....Cameron
'91 Euro GT
I thought the rear tire pressure was too high as well. Someone at the tech inspection told me that 44psi was a good rear tire pressure for this car. I wasn't sure, being my first PCA DE. He stated this so matter of factly that I went with it. Live and learn.
Thanks for the pics. Damn fun to look at pics.
.....Cameron
'91 Euro GT
#11
Dont ever take the advice of any of the DE folks. (unless they have been qualified) generally, ive heard more BS from that group, than imaginable.
show me a group of DE's running 44psi rear, and Ill show you (and have seen) a bunch of guys off track looping on almost all the hard turns!
sounds like you had fun. great shots.
Now, we need to see more of the x-tilo racer!!
mk
show me a group of DE's running 44psi rear, and Ill show you (and have seen) a bunch of guys off track looping on almost all the hard turns!
sounds like you had fun. great shots.
Now, we need to see more of the x-tilo racer!!
mk
Originally posted by Cameron
Thanks for the feedback. I have club sport front springs, stock rear springs. Standard (but pretty new) Boge shocks all around. Tires are Continental ContiSport II's. Re the camber in the front, it should be in spec for a stock alignment and setup. I did not tweek it for DE.
I thought the rear tire pressure was too high as well. Someone at the tech inspection told me that 44psi was a good rear tire pressure for this car. I wasn't sure, being my first PCA DE. He stated this so matter of factly that I went with it. Live and learn.
Thanks for the pics. Damn fun to look at pics.
.....Cameron
'91 Euro GT
Thanks for the feedback. I have club sport front springs, stock rear springs. Standard (but pretty new) Boge shocks all around. Tires are Continental ContiSport II's. Re the camber in the front, it should be in spec for a stock alignment and setup. I did not tweek it for DE.
I thought the rear tire pressure was too high as well. Someone at the tech inspection told me that 44psi was a good rear tire pressure for this car. I wasn't sure, being my first PCA DE. He stated this so matter of factly that I went with it. Live and learn.
Thanks for the pics. Damn fun to look at pics.
.....Cameron
'91 Euro GT