[Fot] Fwd: Hoosier R6 tire pressures

[Bill Babcock]

Wrong meaning if the tires were inflated to optimize the contact patch it
would be shifted to one side of the tire or the other. But I know you know
that. Have you ever considered moving the upper arm inner pivot inward a bit?
I know that would violate the no-hole prescription--is that some religious
thing? You can do a couple of very nice things for your handling by moving the
pivot arm inwards the width of the bolt spacing and drilling just two new
holes. Unfortunately you then need to lengthen the upper arms about half an
inch, but you can make them adjustable when you do that. It decreases camber
gain and allows you to adjust camber at the same time. It might also decrease
bump steer--I suspect it will on TR4s, though I haven't measured it. The inner
pivot of the tie rods on TR3s are inside an imaginary line drawn from the
lower inner suspension pivot and the upper inner suspension pivot. I think
they are on TR4s too. Moving the upper inner pivot inwards will move the line
closer to the tie rod pivot.

At some tracks though you may well be able to optimize your lap times with the
"wrong" camber and over-inflated radial tires. Faster down the the straights,
and not that much slower in the turns. I ran a set of R6s on Peyote briefly
and discovered I could turn faster times at Road America with the tires
overinflated and the camber cranked back a degree to 2.0. Those long straights
demand low rolling friction. Watkins Glen was a tossup--the car was just as
fast on Speedsters with the RIGHT camber and the R6s were pretty heat cycled
out. And it felt better going over the bridge on Speedsters.


On Sep 9, 2010, at 2:52 PM, Greg Lunker Hilyer wrote:

>>> If an overinflated tire makes your car handle better it's because your
camber is wrong.
>
>>>
> While I basically agree, please define "wrong".
> My car has .5 degrees of hard gotten negative camber. It could also be put
in full street trim in about 5 hours - cracked windshield, ratty interior,
stock ride height, skinny wheels and all. Nothing has ever been bent, cut,
drilled, or otherwise molested to prevent it from going back to the two owner,
75.000 mile street car that it is.
>
> Greg "Lunker" Hilyer
> TR4 #314
> Albuquerque NM