What's up with the P-Car photos with 3 wheels on the ground?
10-16-2009, 12:52 PM
#16
Three Wheelin'
I was an active autocrosser for years & it almost seemed like a badge of honor among drivers to see who got their inside wheel the highest. Then I spent some time with a Solo II national champion who emphasized that through trail braking and smooth driving, he tried to Never get an inside wheel off the ground.
In his mind, it was all about weight transfer. If you turn too suddenly, too much weight transfer, the inside wheel goes up (you can see the exact reverse happen on FWD cars that lift an inside rear tire), and you now have only the traction of 3 tires rather than 4.
He worked to be so smooth that he kept all 4 tires on the ground and enhanced traction--and speed.
In his mind, it was all about weight transfer. If you turn too suddenly, too much weight transfer, the inside wheel goes up (you can see the exact reverse happen on FWD cars that lift an inside rear tire), and you now have only the traction of 3 tires rather than 4.
He worked to be so smooth that he kept all 4 tires on the ground and enhanced traction--and speed.
10-16-2009, 11:18 PM
#17
10-17-2009, 07:55 AM
#18
Drifting
It's the result of a too soft suspesion, especially in the rear of a 911, exacerbated by a lack of suspension range (droop) in the front.
Watch Grand-Am or ALMS 911s. They have very stiff springs and you don't see them lifting wheels.
Watch Grand-Am or ALMS 911s. They have very stiff springs and you don't see them lifting wheels.
10-17-2009, 12:46 PM
#21
Rennlist Member
10-17-2009, 12:52 PM
#22
http://www.youtube.com/user/origyns#p/a/u/2/9sRzLAYVPJ8
10-17-2009, 09:08 PM
#24
It could be described as good or bad, depending on the setup. On a road course not all corners are identical, and a car might be setup for the majority of corners, resulting in wheel lift in one or two others. In general it is a function of spring rates and antiroll bars. However, as Andy noted, it could also be caused/exacerbated by the setup itself.
When I had this setup (GT3 bars and short drop links), I could lift in virtually any type of corner. Some examples are below. As you can see, the wheel is lifting a lot. It looks like 4-5 inches - AND the rear tire is starting to lift also. This was on Hoosier R6s.
Just to clarify this piont, weight transfer is unavoidable, and not necessarily bad. You can't affect the total amount of weight transer with roll bars or springs or dampers since weight transfer is a function of ride height (center of gravity), wheel base (or width), and acceleration (lat or long). But you can affect the rate of weight transfer and the amount of suspension travel. The critical issue is controlling and utilizing weight transfer to improve handling under braking / cornering / acceleration.
That being said, you would typically want all 4 wheels in contact with the road so that the workload is properly shared. But that is not always possible.
-td
That being said, you would typically want all 4 wheels in contact with the road so that the workload is properly shared. But that is not always possible.
-td
